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| − | == Indentation == | + | ====[[Python: Install|Install]]==== |
| + | |||
| + | ==Indentation== | ||
Python is an indented language, so the code indentation matters. A good practice is to indent with 4 spaces (if you mix spaces and tabs the code won't work. | Python is an indented language, so the code indentation matters. A good practice is to indent with 4 spaces (if you mix spaces and tabs the code won't work. | ||
| − | == Operators == | + | ==Operators== |
| − | === Arithmetic === | + | ===Arithmetic=== |
<nowiki>+ Addition | <nowiki>+ Addition | ||
| − | - Substraction | + | - Substraction |
| − | * Multiplication | + | * Multiplication |
| − | / Division | + | / Division |
| − | ** Power | + | ** Power |
| − | % Reminder | + | % Reminder |
| − | // Floor division (Reminder is removed)</nowiki> | + | // Floor division (Reminder is removed)</nowiki> |
| − | === Comparison === | + | ===Comparison=== |
<nowiki> | <nowiki> | ||
| − | == Equal | + | == Equal |
| − | != Not equal | + | != Not equal |
| − | > Greater | + | > Greater |
| − | >= Greater or equal | + | >= Greater or equal |
| − | < Smaller | + | < Smaller |
| − | <= Smaller or equal | + | <= Smaller or equal |
| − | <> Similar to !=</nowiki> | + | <> Similar to !=</nowiki> |
| − | === Assignment === | + | ===Assignment=== |
<nowiki> | <nowiki> | ||
| − | = Simple assignment | + | = Simple assignment |
| − | += Add and as | + | += Add and as |
| − | -= Substract and assignment | + | -= Substract and assignment |
| − | *= Multiply and assignment | + | *= Multiply and assignment |
| − | /= Divide and assignment | + | /= Divide and assignment |
| − | %= Modulus and assignment | + | %= Modulus and assignment |
| − | **= Exponent and assignment | + | **= Exponent and assignment |
| − | //= Floor Divisionn and assignment</nowiki> | + | //= Floor Divisionn and assignment</nowiki> |
| − | === Bitwise operators === | + | ===Bitwise operators=== |
They perform operations on binary terms. a= 8 → 100; b= 9 → 101; a & b → 100 | They perform operations on binary terms. a= 8 → 100; b= 9 → 101; a & b → 100 | ||
<nowiki> | <nowiki> | ||
| − | $ Binary AND | + | $ Binary AND |
| − | | Binary OR | + | | Binary OR |
| − | ^ Binary XOR | + | ^ Binary XOR |
| − | ~ Binary complement | + | ~ Binary complement |
| − | << Binary left shift | + | << Binary left shift |
| − | >> Binary right shift</nowiki> | + | >> Binary right shift</nowiki> |
| − | === Logic === | + | ===Logic=== |
<nowiki> | <nowiki> | ||
| − | and | + | and |
| − | or | + | or |
| − | not</nowiki> | + | not</nowiki> |
| − | === Membership operators === | + | ===Membership operators=== |
in<br /> | in<br /> | ||
not in<br /> | not in<br /> | ||
| − | == Variables == | + | ==Variables== |
| − | === Numbers === | + | ===Numbers=== |
| − | === String === | + | |
| + | ====0 padding 2 digits==== | ||
| + | <syntaxhighlight lang="python3"> | ||
| + | print("{:02d}".format(1)) | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ===String=== | ||
String assingment:<br /> | String assingment:<br /> | ||
MyString = 'Hello World' OR MyString = "Hello World"<br /> | MyString = 'Hello World' OR MyString = "Hello World"<br /> | ||
| Line 85: | Line 93: | ||
len(MyString) → returns the lenght of a string | len(MyString) → returns the lenght of a string | ||
| − | === Collections === | + | ===Collections=== |
| − | ==== List ==== | + | ====List==== |
Collection - allows us to put many values in a single variable. | Collection - allows us to put many values in a single variable. | ||
Simple variables are not collections. The previous value is overwritten when changed. | Simple variables are not collections. The previous value is overwritten when changed. | ||
| − | * A List is made up of list 'constants'. Lists are surrounded by square brackets [] and the constants in the list are separated by commas. ([2,4,6,8]) | + | |
| − | * A List element can be any Python object, even another list | + | *A List is made up of list 'constants'. Lists are surrounded by square brackets [] and the constants in the list are separated by commas. ([2,4,6,8]) |
| − | * A List can be empty | + | *A List element can be any Python object, even another list |
| − | * Lists are mutable (they can be changed) | + | *A List can be empty |
| − | * When len() is used on a list, it counts the number of constants that make up the list. (not the number of characters) | + | *Lists are mutable (they can be changed) |
| − | * Lists can be concatenated using + | + | *When len() is used on a list, it counts the number of constants that make up the list. (not the number of characters) |
| − | * Lists can be sliced | + | *Lists can be concatenated using + |
| − | * List is a unique type that can be checked using type() (result: <type 'list'>) | + | *Lists can be sliced |
| − | * An empty list can be created with list() | + | *List is a unique type that can be checked using type() (result: <type 'list'>) |
| − | * Lists can be tested for contents using in/not in | + | *An empty list can be created with list() |
| − | * List is an ordered sequence | + | *Lists can be tested for contents using in/not in |
| − | * A list can be sorted with .sort(). Sort changes the list permanently. | + | *List is an ordered sequence |
| − | * sorted(list) → Returns a list sorted. | + | *A list can be sorted with .sort(). Sort changes the list permanently. |
| − | * Methods: append, count, extend, index, insert, pop, remove, reverse, sort | + | *sorted(list) → Returns a list sorted. |
| − | * Functions len() - find length, max() - find highest value, min() - find lowest value, sum() - add all values average can be found with sum()/len() | + | *Methods: append, count, extend, index, insert, pop, remove, reverse, sort |
| + | *Functions len() - find length, max() - find highest value, min() - find lowest value, sum() - add all values average can be found with sum()/len() | ||
| + | *reversed list: | ||
| + | **list.reverse() | ||
| + | **list[::-1] | ||
| + | **reversed(list) | ||
'''Del''' | '''Del''' | ||
| Line 109: | Line 122: | ||
example: a = [1, 2, 3, 4, 5] del a[0] returns [2, 3, 4, 5] | example: a = [1, 2, 3, 4, 5] del a[0] returns [2, 3, 4, 5] | ||
| − | ==== Tuple ==== | + | <br /> |
| + | |||
| + | ====List comprehension==== | ||
| + | flatten list<syntaxhighlight lang="python3"> | ||
| + | def flatten(list_of_lists): | ||
| + | return [element for secondary_list in list_of_lists for element in secondary_list ] | ||
| + | |||
| + | a = [[1,2,3], [3,4,5], ["a", "b"]] | ||
| + | flatten(a) | ||
| + | |||
| + | Out[29]: [1, 2, 3, 3, 4, 5, 'a', 'b'] | ||
| + | </syntaxhighlight><br /> | ||
| + | |||
| + | ====Tuple==== | ||
Inmutable, declared by () | Inmutable, declared by () | ||
| − | * My_tuple = (3, 2, 1) | + | |
| + | *My_tuple = (3, 2, 1) | ||
| + | |||
You can iterate trough tuples.<br /> | You can iterate trough tuples.<br /> | ||
You can also refer to the items of a tuple like in a list.<br /> | You can also refer to the items of a tuple like in a list.<br /> | ||
| Line 175: | Line 203: | ||
</source> | </source> | ||
| − | ==== Dictionary ==== | + | ====Dictionary==== |
Key - Value pairs. They are called diferent in diferent languages:<br /> | Key - Value pairs. They are called diferent in diferent languages:<br /> | ||
dictionary[key] = value <br /> | dictionary[key] = value <br /> | ||
| − | * Perl → Associative arrays | + | *Perl → Associative arrays |
| − | * Java → Properties, Map or HashMap | + | *Java → Properties, Map or HashMap |
| − | * C# → Property bag | + | *C# → Property bag |
| + | |||
<br /> | <br /> | ||
Declarationn and assigment:<br /> | Declarationn and assigment:<br /> | ||
There are two posible ways to declare them: | There are two posible ways to declare them: | ||
| − | * purse = dict() | + | |
| − | * puse = {} | + | *purse = dict() |
| + | *puse = {} | ||
<source lang="python"> | <source lang="python"> | ||
purse = dict() | purse = dict() | ||
| Line 201: | Line 231: | ||
purse.get(name, default_value) | purse.get(name, default_value) | ||
'''Other methods and functions'''<br /> | '''Other methods and functions'''<br /> | ||
| − | * list(purse) → Returns a list of keys. | + | |
| − | * dict.keys() → Returns a list of keys. | + | *list(purse) → Returns a list of keys. |
| − | * dict.values() → Returns a list of values. | + | *dict.keys() → Returns a list of keys. |
| − | * dict.items → Returns a list of tuples ( [(key, value), (key, value)...] ) | + | *dict.values() → Returns a list of values. |
| + | *dict.items → Returns a list of tuples ( [(key, value), (key, value)...] ) | ||
| + | |||
''' Word count using files and dictionarys'''<br /> | ''' Word count using files and dictionarys'''<br /> | ||
<source lang="python"> | <source lang="python"> | ||
| Line 226: | Line 258: | ||
</source> | </source> | ||
| − | == Conditional == | + | ==Conditional== |
| − | === if/elif/else === | + | ===if/elif/else=== |
<source lang="python"> | <source lang="python"> | ||
if a < 10: | if a < 10: | ||
| Line 237: | Line 269: | ||
</source> | </source> | ||
| − | === try/except/finally === | + | ===try/except/finally=== |
<source lang="python"> | <source lang="python"> | ||
try: | try: | ||
| Line 247: | Line 279: | ||
</source> | </source> | ||
| − | == Loops == | + | ===Print Exception=== |
| − | === For === | + | <syntaxhighlight lang="python3"> |
| + | import traceback | ||
| + | |||
| + | def bug(): | ||
| + | my_dict = {'a': 9} | ||
| + | try: | ||
| + | return my_dict['b'] | ||
| + | except KeyError: | ||
| + | print(traceback.format_exc()) | ||
| + | return None | ||
| + | </syntaxhighlight><br /> | ||
| + | ==Loops== | ||
| + | ===For=== | ||
<source lang="python"> | <source lang="python"> | ||
NumberList = [1, 3, 7, 12, 24] | NumberList = [1, 3, 7, 12, 24] | ||
| Line 260: | Line 304: | ||
</source> | </source> | ||
| − | === while === | + | ===while=== |
<source lang="python"> | <source lang="python"> | ||
CtrlNum = 7 | CtrlNum = 7 | ||
| Line 268: | Line 312: | ||
</source> | </source> | ||
| − | == Functions == | + | ==Functions== |
All arguments in Python are passed by reference, if you change a variable value inside a function it will be changed at the calling function. | All arguments in Python are passed by reference, if you change a variable value inside a function it will be changed at the calling function. | ||
<source lang="python"> | <source lang="python"> | ||
| Line 278: | Line 322: | ||
print arg | print arg | ||
</source> | </source> | ||
| − | == Regular Expressions == | + | ==Regular Expressions== |
<nowiki> | <nowiki> | ||
| − | + | ^ → Matches the beginning of a line | |
| − | + | $ → Matches the end of a line | |
| − | + | . → Matches any character | |
| − | + | \s → Matches any whitespace | |
| − | + | \S → Matches any non-whitespace | |
| − | + | * → Repeats a character 0 or more times | |
| − | + | *? → Repeats a character 0 or more times (non-greedy) | |
| − | + | + → Repeats a character 1 or more times | |
| − | + | +? → Repeats a character 1 or more times (non-greedy) | |
| − | + | [aeiou] → Matches a single character in the listed set | |
| − | + | [^XYZ] → Matches a single character NOT in the listed set | |
| − | [a-z0-9] → The set of characters can include a range | + | [a-z0-9] → The set of characters can include a range |
| − | + | ( → Indicates where string extraction is to start | |
| − | + | ) → Indicates where string extraction is to end</nowiki> | |
\ → Escape character | \ → Escape character | ||
| − | === Regular Expression Module === | + | ===Regular Expression Module=== |
It must be imported at the begining of a program: | It must be imported at the begining of a program: | ||
<source lang="python"> | <source lang="python"> | ||
import re | import re | ||
</source> | </source> | ||
| − | * re.search(re_string, string) → similar to find() | + | |
| − | * re.findall(re_string, string) → similar to find, returns a list | + | *re.search(re_string, string) → similar to find() |
| − | * re.match(re_string, string) | + | *re.findall(re_string, string) → similar to find, returns a list |
| + | *re.match(re_string, string) | ||
<source lang="python"> | <source lang="python"> | ||
| Line 312: | Line 357: | ||
print line | print line | ||
</source> | </source> | ||
| − | == Date == | + | ==Date== |
| − | === Today as string === | + | ===Today as string=== |
<source lang="python"> | <source lang="python"> | ||
import datetime | import datetime | ||
datetime.date.today().strftime("%B %d, %Y") | datetime.date.today().strftime("%B %d, %Y") | ||
</source> | </source> | ||
| − | === String date to date type === | + | ===String date to date type=== |
<source lang="python"> | <source lang="python"> | ||
from datetime import datetime | from datetime import datetime | ||
| Line 325: | Line 370: | ||
</source> | </source> | ||
| − | == Files == | + | ==Files== |
'''Counting lines in a file''' | '''Counting lines in a file''' | ||
<source lang="python"> | <source lang="python"> | ||
| Line 366: | Line 411: | ||
print "\n"+("That was "+fname+".").center(40) | print "\n"+("That was "+fname+".").center(40) | ||
</source> | </source> | ||
| − | === CSV === | + | ===CSV=== |
<source lang="python"> | <source lang="python"> | ||
import csv | import csv | ||
| Line 412: | Line 457: | ||
</source> | </source> | ||
| − | == Class == | + | ==Run System Commands== |
| + | |||
| + | ===Python >= 3.5=== | ||
| + | <syntaxhighlight lang="python3"> | ||
| + | def _run_command(command): | ||
| + | log.debug("Command: {}".format(command)) | ||
| + | result = subprocess.run(command, shell=True, capture_output=True) | ||
| + | |||
| + | if result.stderr: | ||
| + | raise subprocess.CalledProcessError( | ||
| + | returncode=result.returncode, | ||
| + | cmd=result.args, | ||
| + | stderr=f"{result.stdout}\n{result.stderr}" | ||
| + | ) | ||
| + | if result.stdout: | ||
| + | log.debug("Command Result: {}".format(result.stdout.decode('utf-8'))) | ||
| + | return result | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ==Class== | ||
<source lang="python"> | <source lang="python"> | ||
class MyClass: | class MyClass: | ||
| Line 438: | Line 502: | ||
</source> | </source> | ||
| − | * issubclass(sub, sup) | + | *issubclass(sub, sup) |
| − | * isinstance(obj, Class) | + | *isinstance(obj, Class) |
'''Generic functionality that can be overriden in own classes'''<br /> | '''Generic functionality that can be overriden in own classes'''<br /> | ||
| Line 451: | Line 515: | ||
'''Hiding attributes''' | '''Hiding attributes''' | ||
attributes that start with a __ wont be visible to others<br /> | attributes that start with a __ wont be visible to others<br /> | ||
| − | == os.system() == | + | |
| + | ===Subclasing builtins=== | ||
| + | |||
| + | ====Perfect dict subclass==== | ||
| + | <syntaxhighlight lang="python3"> | ||
| + | # has a ton of errors: https://stackoverflow.com/questions/3387691/how-to-perfectly-override-a-dict | ||
| + | |||
| + | class LowerDict(dict): | ||
| + | __slots__ = () | ||
| + | |||
| + | def _process_args(mapping=(), **kwargs): | ||
| + | if hasattr(mapping, items): | ||
| + | mapping = getattr(mapping, items)() | ||
| + | return ((ensure_lower(k), v) for k, v in chain(mapping, getattr(kwargs, items)())) | ||
| + | |||
| + | def __init__(self, mapping=(), **kwargs): | ||
| + | super(LowerDict, self).__init__(self._process_args(mapping, **kwargs)) | ||
| + | |||
| + | def __getitem__(self, k): | ||
| + | return super(LowerDict, self).__getitem__(ensure_lower(k)) | ||
| + | def __setitem__(self, k, v): | ||
| + | return super(LowerDict, self).__setitem__(ensure_lower(k), v) | ||
| + | |||
| + | def __delitem__(self, k): | ||
| + | return super(LowerDict, self).__delitem__(ensure_lower(k)) | ||
| + | |||
| + | def get(self, k, default=None): | ||
| + | return super(LowerDict, self).get(ensure_lower(k), default) | ||
| + | |||
| + | def setdefault(self, k, default=None): | ||
| + | return super(LowerDict, self).setdefault(ensure_lower(k), default) | ||
| + | |||
| + | def pop(self, k, v=_RaiseKeyError): | ||
| + | if v is _RaiseKeyError: | ||
| + | return super(LowerDict, self).pop(ensure_lower(k)) | ||
| + | return super(LowerDict, self).pop(ensure_lower(k), v) | ||
| + | |||
| + | def update(self, mapping=(), **kwargs): | ||
| + | super(LowerDict, self).update(self._process_args(mapping, **kwargs)) | ||
| + | def __contains__(self, k): | ||
| + | return super(LowerDict, self).__contains__(ensure_lower(k)) | ||
| + | |||
| + | def copy(self): # don't delegate w/ super - dict.copy() -> dict :( | ||
| + | return type(self)(self) | ||
| + | |||
| + | @classmethod | ||
| + | def fromkeys(cls, keys, v=None): | ||
| + | return super(LowerDict, cls).fromkeys((ensure_lower(k) for k in keys), v) | ||
| + | |||
| + | def __repr__(self): | ||
| + | return '{0}({1})'.format(type(self).__name__, super(LowerDict, self).__repr__()) | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ====Not so perfect dict like object==== | ||
| + | <syntaxhighlight lang="python3"> | ||
| + | from collections.abc import MutableMapping | ||
| + | |||
| + | |||
| + | class TransformedDict(MutableMapping): | ||
| + | """A dictionary that applies an arbitrary key-altering | ||
| + | function before accessing the keys""" | ||
| + | |||
| + | def __init__(self, *args, **kwargs): | ||
| + | self.store = dict() | ||
| + | self.update(dict(*args, **kwargs)) # use the free update to set keys | ||
| + | |||
| + | def __getitem__(self, key): | ||
| + | return self.store[self._keytransform(key)] | ||
| + | |||
| + | def __setitem__(self, key, value): | ||
| + | self.store[self._keytransform(key)] = value | ||
| + | |||
| + | def __delitem__(self, key): | ||
| + | del self.store[self._keytransform(key)] | ||
| + | |||
| + | def __iter__(self): | ||
| + | return iter(self.store) | ||
| + | |||
| + | def __len__(self): | ||
| + | return len(self.store) | ||
| + | |||
| + | def _keytransform(self, key): | ||
| + | return key | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ==os.system()== | ||
To execute a Linux command from Python: | To execute a Linux command from Python: | ||
<source lang="python"> | <source lang="python"> | ||
os.system(command) → returns exit status | os.system(command) → returns exit status | ||
</source> | </source> | ||
| − | == Database Access == | + | ==Database Access== |
| − | === MySQLdb === | + | ===MySQLdb=== |
'''Table creation''' | '''Table creation''' | ||
<source lang="python"> | <source lang="python"> | ||
| Line 515: | Line 664: | ||
'''Read example''' | '''Read example''' | ||
Once the query is made you can: | Once the query is made you can: | ||
| + | |||
*fetchone() | *fetchone() | ||
*fetchall() | *fetchall() | ||
| Line 553: | Line 703: | ||
db.close() | db.close() | ||
</source> | </source> | ||
| − | === PostgreSQL === | + | ===PostgreSQL=== |
Refer to: [https://wiki.python.org/moin/PostgreSQL PostgreSQL] | Refer to: [https://wiki.python.org/moin/PostgreSQL PostgreSQL] | ||
| − | === Other === | + | ===Other=== |
Refer to: [https://wiki.python.org/moin/DatabaseInterfaces Database Interfaces] | Refer to: [https://wiki.python.org/moin/DatabaseInterfaces Database Interfaces] | ||
| − | == ssh tunneling == | + | ==ssh tunneling== |
<source lang="python"> | <source lang="python"> | ||
import subprocess | import subprocess | ||
| Line 567: | Line 717: | ||
</source> | </source> | ||
| − | == Multithreading == | + | ==Multithreading== |
<source lang="python"> | <source lang="python"> | ||
#!/usr/bin/python | #!/usr/bin/python | ||
| Line 596: | Line 746: | ||
import threading | import threading | ||
</source> | </source> | ||
| − | == Python GUI Programming == | + | ==Python GUI Programming== |
| + | |||
*Tkinter: Tkinter is the Python interface to the Tk GUI toolkit shipped with Python. We would look this option in this tutorial. | *Tkinter: Tkinter is the Python interface to the Tk GUI toolkit shipped with Python. We would look this option in this tutorial. | ||
*wxPython: This is an open-source Python interface for wxWindows http://wxpython.org. | *wxPython: This is an open-source Python interface for wxWindows http://wxpython.org. | ||
| Line 611: | Line 762: | ||
</source> | </source> | ||
'''Widgets''' | '''Widgets''' | ||
| + | |||
*Button The Button widget is used to display buttons in your application. | *Button The Button widget is used to display buttons in your application. | ||
*Canvas The Canvas widget is used to draw shapes, such as lines, ovals, polygons and rectangles, in your application. | *Canvas The Canvas widget is used to draw shapes, such as lines, ovals, polygons and rectangles, in your application. | ||
| Line 632: | Line 784: | ||
'''Standard attributes''' | '''Standard attributes''' | ||
| + | |||
*Dimensions | *Dimensions | ||
*Colors | *Colors | ||
| Line 641: | Line 794: | ||
'''Geometry Management''' | '''Geometry Management''' | ||
| + | |||
*The pack() Method - This geometry manager organizes widgets in blocks before placing them in the parent widget. | *The pack() Method - This geometry manager organizes widgets in blocks before placing them in the parent widget. | ||
*The grid() Method - This geometry manager organizes widgets in a table-like structure in the parent widget. | *The grid() Method - This geometry manager organizes widgets in a table-like structure in the parent widget. | ||
| Line 647: | Line 801: | ||
For further reference visit: tutorialspoint.com/python/python_gui_programming.htm | For further reference visit: tutorialspoint.com/python/python_gui_programming.htm | ||
| − | == Enable auto complete in python interpreter == | + | ==Enable auto complete in python interpreter== |
Create a file in your home directory named: .pythonrc<br /> | Create a file in your home directory named: .pythonrc<br /> | ||
Content of this file: | Content of this file: | ||
| Line 661: | Line 815: | ||
To test it import a library, write librariname. and hit tab twice | To test it import a library, write librariname. and hit tab twice | ||
| + | |||
| + | ==Delete *.pyc== | ||
| + | find . -name "*.pyc" -exec rm -rf {} \; | ||
| + | |||
| + | ==format hex== | ||
| + | |||
| + | |||
| + | Use the format() function with a '02x' format. | ||
| + | |||
| + | >>> format(255, '02x')<br /> | ||
| + | 'ff'<br /> | ||
| + | >>> format(2, '02x')<br /> | ||
| + | '02'<br /> | ||
| + | |||
| + | The 02 part tells format() to use at least 2 digits and to use zeros to pad it to length, x <br />means lower-case hexadecimal.<br /> | ||
| + | |||
| + | The Format Specification Mini Language also gives you X for uppercase hex output, and you can <br />prefix the field width with # to include a 0x or 0X prefix (depending on wether you used <br />x or X as the formatter). Just take into account that you need to adjust the field width <br />to allow for those extra 2 characters:<br /> | ||
| + | |||
| + | >>> format(255, '02X')<br /> | ||
| + | 'FF'<br /> | ||
| + | >>> format(255, '#04x')<br /> | ||
| + | '0xff'<br /> | ||
| + | >>> format(255, '#04X')<br /> | ||
| + | '0XFF'<br /> | ||
| + | |||
| + | ==Command completion== | ||
| + | $ nano ~/.pythonrc | ||
| + | |||
| + | <source lang="python"> | ||
| + | # ~/.pythonrc | ||
| + | # enable syntax completion | ||
| + | try: | ||
| + | import readline | ||
| + | except ImportError: | ||
| + | print("Module readline not available.") | ||
| + | else: | ||
| + | import rlcompleter | ||
| + | readline.parse_and_bind("tab: complete") | ||
| + | </source> | ||
| + | |||
| + | $ nano ~/.bashrc | ||
| + | <source lang="bash"> | ||
| + | export PYTHONSTARTUP=~/.pythonrc</source> | ||
| + | |||
| + | ==nose debug== | ||
| + | nosetests --debug=nose,nose.importer --debug-log=nose_debug <your usual args> | ||
| + | |||
| + | ==Publish Python Package== | ||
| + | Upload a package to pypi. This would make your package available with: | ||
| + | pip install mypackage | ||
| + | ===With setup.py=== | ||
| + | nano ~/.pypirc | ||
| + | <nowiki>[distutils] | ||
| + | index-servers = | ||
| + | pypi | ||
| + | pypitest | ||
| + | |||
| + | [pypi] | ||
| + | repository=https://upload.pypi.org/legacy/ | ||
| + | username=your_username | ||
| + | password=your_password | ||
| + | |||
| + | [pypitest] | ||
| + | repository=https://testpypi.python.org/pypi | ||
| + | username=your_username | ||
| + | password=your_password</nowiki> | ||
| + | Adjust .pypirc permissions | ||
| + | chmod 600 ~/.pypirc | ||
| + | In your project, create a setup.py | ||
| + | <source lang="python">import os | ||
| + | from setuptools import setup, find_packages | ||
| + | |||
| + | # from distutils.core import setup | ||
| + | |||
| + | # allow setup.py to be run from any path | ||
| + | os.chdir(os.path.normpath(os.path.join(os.path.abspath(__file__), os.pardir))) | ||
| + | |||
| + | |||
| + | def here(name): | ||
| + | return os.path.join( | ||
| + | os.path.dirname(os.path.abspath(__file__)), | ||
| + | name) | ||
| + | |||
| + | |||
| + | def read(name, mode='rb', encoding='utf8'): | ||
| + | os.system('pandoc --from=markdown --to=rst --output=README.rst README.md') | ||
| + | if os.path.exists('README.rst'): | ||
| + | long_description = open('README.rst').read() | ||
| + | else: | ||
| + | try: | ||
| + | with open(here(name), mode) as fp: | ||
| + | long_description = fp.read() | ||
| + | except IOError: | ||
| + | return 'Error generating long description: {} File not found'.format(here(name)) | ||
| + | return long_description | ||
| + | |||
| + | # Development Status :: 1 - Planning | ||
| + | # Development Status :: 2 - Pre-Alpha | ||
| + | # Development Status :: 3 - Alpha | ||
| + | # Development Status :: 4 - Beta | ||
| + | # Development Status :: 5 - Production/Stable | ||
| + | # Development Status :: 6 - Mature | ||
| + | # Development Status :: 7 - Inactive | ||
| + | |||
| + | |||
| + | license_classifiers = { | ||
| + | 'MIT license': 'License :: OSI Approved :: MIT License', | ||
| + | 'BSD license': 'License :: OSI Approved :: BSD License', | ||
| + | 'ISC license': 'License :: OSI Approved :: ISC License (ISCL)', | ||
| + | 'Apache Software License 2.0': 'License :: OSI Approved :: Apache Software License', | ||
| + | 'GNU General Public License v3': 'License :: OSI Approved :: GNU General Public License v3 (GPLv3)' | ||
| + | } | ||
| + | |||
| + | setup( | ||
| + | name='CheKnife', | ||
| + | version='v0.0.6b2', | ||
| + | packages=find_packages(), | ||
| + | url='https://git.herrerosolis.com/Misc/CheKnife', | ||
| + | download_url='https://git.herrerosolis.com/Misc/CheKnife/-/archive/v0.0.6b2/CheKnife-v0.0.6b2.tar.gz', | ||
| + | license='MIT license', | ||
| + | author='Rafael Herrero Solis', | ||
| + | author_email='rafahsolis@hotmail.com', | ||
| + | keywords=['CheKnife', 'Swiss', 'Army', 'Knife', 'Swiss Army Knife'], | ||
| + | description='Python Utilities', | ||
| + | long_description=read('README.md'), | ||
| + | test_suite='nose.collector', | ||
| + | tests_require=['nose', 'six'], | ||
| + | install_requires=[ | ||
| + | 'six>=1.10.0', | ||
| + | 'future>=0.16.0', | ||
| + | 'pycryptodome>=3.6.1', | ||
| + | 'configparser>=3.5.0' | ||
| + | ], | ||
| + | classifiers=[ | ||
| + | 'License :: OSI Approved :: MIT License', | ||
| + | 'Development Status :: 3 - Alpha', | ||
| + | 'License :: OSI Approved :: Apache Software License', | ||
| + | 'Programming Language :: Python :: 3.6', | ||
| + | ], | ||
| + | )</source> | ||
| + | |||
| + | nano setup.cfg | ||
| + | <nowiki>[metadata] | ||
| + | description-file = README.md</nowiki> | ||
| + | |||
| + | nano LICENSE | ||
| + | <nowiki>The MIT License | ||
| + | |||
| + | SPDX short identifier: MIT | ||
| + | |||
| + | Copyright <YEAR> <COPYRIGHT HOLDER> | ||
| + | |||
| + | Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: | ||
| + | |||
| + | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. | ||
| + | |||
| + | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.</nowiki> | ||
| + | Test and upload | ||
| + | <source lang="bash">python setup.py register -r pypitest | ||
| + | python setup.py sdist upload -r pypitest | ||
| + | python setup.py register -r pypi | ||
| + | python setup.py sdist upload -r pypi</source> | ||
| + | |||
| + | ===With twine=== | ||
| + | https://packaging.python.org/tutorials/packaging-projects/ | ||
| + | |||
| + | ==Change PyPi== | ||
| + | ===Using PyPi Local Repository=== | ||
| + | nano ~/.pip/pip.conf | ||
| + | <nowiki>[global] | ||
| + | index-url= http://10.255.0.21/pypi/simple | ||
| + | trusted-host= 10.255.0.21</nowiki> | ||
| + | |||
| + | ==Using pip behind proxy== | ||
| + | sudo pip --proxy http://proxy.hell:3128 install requests | ||
| + | |||
| + | ==Publish to PyPi== | ||
| + | Create the file ~/.pypirc | ||
| + | <nowiki>[distutils] | ||
| + | index-servers = | ||
| + | pypi | ||
| + | pypitest | ||
| + | |||
| + | [pypi] | ||
| + | repository=https://pypi.python.org/pypi | ||
| + | username= | ||
| + | password= | ||
| + | |||
| + | [pypitest] | ||
| + | repository=https://test.pypi.org/legacy | ||
| + | username= | ||
| + | password= | ||
| + | </nowiki> | ||
| + | |||
| + | Test | ||
| + | python setup.py register -r pypitest | ||
| + | python setup.py sdist upload -r pypitest | ||
| + | |||
| + | Upload | ||
| + | python setup.py register -r pypi | ||
| + | python setup.py sdist upload -r pypi | ||
| + | |||
| + | == requirements.txt == | ||
| + | |||
| + | === Platform conditional === | ||
| + | <syntaxhighlight lang="text"> | ||
| + | psycopg2-binary~=2.9.7; platform_system == "Linux" | ||
| + | psycopg2~=2.9.6; platform_system == "Windows" | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ==AWS boto3 EC2== | ||
| + | <source lang="python"> | ||
| + | import boto3 | ||
| + | client = boto3.client('ec2', aws_access_key_id="AKI.............Q", aws_secret_access_key="2..........................s", region_name='us-east-1') | ||
| + | ec2_regions = [region['RegionName'] for region in client.describe_regions()['Regions']] | ||
| + | instances = [] | ||
| + | for region in ec2_regions: | ||
| + | conn = boto3.resource('ec2', aws_access_key_id="AKIAJBWPORUPPGNSUWXQ", aws_secret_access_key="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", region_name=region) | ||
| + | instances += conn.instances.filter() | ||
| + | i = instances[0] | ||
| + | i.public_dns_name | ||
| + | i.public_ip_address | ||
| + | </source> | ||
| + | [[Category:Python]] | ||
Latest revision as of 08:08, 11 September 2024
Install
Indentation
Python is an indented language, so the code indentation matters. A good practice is to indent with 4 spaces (if you mix spaces and tabs the code won't work.
Operators
Arithmetic
+ Addition
- Substraction
* Multiplication
/ Division
** Power
% Reminder
// Floor division (Reminder is removed)
Comparison
== Equal
!= Not equal
> Greater
>= Greater or equal
< Smaller
<= Smaller or equal
<> Similar to !=
Assignment
= Simple assignment
+= Add and as
-= Substract and assignment
*= Multiply and assignment
/= Divide and assignment
%= Modulus and assignment
**= Exponent and assignment
//= Floor Divisionn and assignment
Bitwise operators
They perform operations on binary terms. a= 8 → 100; b= 9 → 101; a & b → 100
$ Binary AND
| Binary OR
^ Binary XOR
~ Binary complement
<< Binary left shift
>> Binary right shift
Logic
and
or
not
Membership operators
in
not in
Variables
Numbers
0 padding 2 digits
print("{:02d}".format(1))
String
String assingment:
MyString = 'Hello World' OR MyString = "Hello World"
Strings can be subset sliced:
MyString = "Hello world"
MyString[0:4]
Hel
in operator: to check if a substring is contained in a string
String library:
str.lower()
str.upper()
str.capitalize() → Uppercases 1st char
str.center(width[, fillchar])
str.startswith(preffix[, start[, end]])
str.endswith(suffix[, start[, end]])
str.find(substring[, start[, end]])
str.lstrip([chars])
str.rstrip([chars])
str.strip([chars])
str.replace(old, new[, count])see also threading module:
import threading
str.split([char])
len(MyString) → returns the lenght of a string
Collections
List
Collection - allows us to put many values in a single variable. Simple variables are not collections. The previous value is overwritten when changed.
- A List is made up of list 'constants'. Lists are surrounded by square brackets [] and the constants in the list are separated by commas. ([2,4,6,8])
- A List element can be any Python object, even another list
- A List can be empty
- Lists are mutable (they can be changed)
- When len() is used on a list, it counts the number of constants that make up the list. (not the number of characters)
- Lists can be concatenated using +
- Lists can be sliced
- List is a unique type that can be checked using type() (result: <type 'list'>)
- An empty list can be created with list()
- Lists can be tested for contents using in/not in
- List is an ordered sequence
- A list can be sorted with .sort(). Sort changes the list permanently.
- sorted(list) → Returns a list sorted.
- Methods: append, count, extend, index, insert, pop, remove, reverse, sort
- Functions len() - find length, max() - find highest value, min() - find lowest value, sum() - add all values average can be found with sum()/len()
- reversed list:
- list.reverse()
- list[::-1]
- reversed(list)
Del
Removes an item from a list.
example: a = [1, 2, 3, 4, 5] del a[0] returns [2, 3, 4, 5]
List comprehension
flatten list
def flatten(list_of_lists):
return [element for secondary_list in list_of_lists for element in secondary_list ]
a = [[1,2,3], [3,4,5], ["a", "b"]]
flatten(a)
Out[29]: [1, 2, 3, 3, 4, 5, 'a', 'b']
Tuple
Inmutable, declared by ()
- My_tuple = (3, 2, 1)
You can iterate trough tuples.
You can also refer to the items of a tuple like in a list.
My_tuple[0]
3
They support multple assignment, usefull for example to iterate trough dictionaries:
d = dict()
d['steve'] = 2
d['susan'] = 4
for (k, v) in d.items():
print k, v
Tuples are comparable. They compare the leftmost first, then the next and so on...
>>> (0, 1, 2) < (5, 1, 2)
True
>>> (0, 1, 30000000) < (0, 3, 1)
True
To sort dictionaries by keys.
>>> d = {'c':22, 'b':1, 'a':10}
>>> t = d.items()
>>> t
[('c', 22), ('b',1), ('a', 10)]
>>> t.sort()
>>> t
[('a', 10), ('b',1), ('c', 22)]
To sort by value:
c = {'c':22, 'b':1, 'a':10}
tmp = list()
for k, v in c.items():
tmp.append( (v, k) )
tmp.sort(reverse = True)
print tmp
[(22, 'c'), (10, 'a'), (1, 'b')]
The same sort by value with list comprehension
c = {'c':22, 'b':1, 'a':10}
print sorted( [ (v,k) for k,v in c.items() ] )
Top 10 most common words.
fhand = open('romeo.txt')
counts = dict()
for line in fhand:
words = line.split()
for word in words:
counts[word] = counts.get(word, 0) +1
lst = list()
for key, val in counts.items():
lst.append((val, key))
lst.sort(reverse = True)
for val, key in lst[:10]
print key, val
Dictionary
Key - Value pairs. They are called diferent in diferent languages:
dictionary[key] = value
- Perl → Associative arrays
- Java → Properties, Map or HashMap
- C# → Property bag
Declarationn and assigment:
There are two posible ways to declare them:
- purse = dict()
- puse = {}
purse = dict()
purse['money'] = 12
purse['candy'] = 3
print purse['money']
purse = {'money': 12, 'candy' = 3}
get() method:
If you try to retrieve a value for a key that doesn't exist you would get a traceback error.
To avoid this you should use the get() method, that returns the default value if the key doesn't exist:
purse.get(name, default_value)
Other methods and functions
- list(purse) → Returns a list of keys.
- dict.keys() → Returns a list of keys.
- dict.values() → Returns a list of values.
- dict.items → Returns a list of tuples ( [(key, value), (key, value)...] )
Word count using files and dictionarys
counts = dict()
file_path = raw_input('Enter file name: ')
file_handle = open(file_path, 'r')
text = file_handle.read()
words = text.split()
for word in words:
counts[word] = counts.get(word, 0) + 1
bigCount = None
bigWord = None
for word, count in counts.items():
if bigCount is None or count > bigCount:
bigWord = word
bigCount = count
print 'Most frequent word: ', bigWord, '\nFrequency: ', bigCount'
Conditional
if/elif/else
if a < 10:
print "Less than 10"
elif a >= 10 and a < 20:
print "a greater or equal to 10 and less than 20"
else:
print "a greater or equal to 20"
try/except/finally
try:
file = open("test.txt")
except:
print "Could not open file"
finally:
print "This part will be executed at the end whether the open fails or not"
Print Exception
import traceback
def bug():
my_dict = {'a': 9}
try:
return my_dict['b']
except KeyError:
print(traceback.format_exc())
return None
Loops
For
NumberList = [1, 3, 7, 12, 24]
for number in NumberList:
print number
Another way:
for i in range(0, len(NumberList)-1):
print NumberList[i]
while
CtrlNum = 7
while CtrllNum > 3:
print CtrlNum
CtrlNum -= 1
Functions
All arguments in Python are passed by reference, if you change a variable value inside a function it will be changed at the calling function.
def MyFunction(formal_arg, optional_arg = None, *variable_lenght_args):
print formal_arg
if optional_arg:
print optional_arg
for arg in variable_lenght_args:
print arg
Regular Expressions
^ → Matches the beginning of a line
$ → Matches the end of a line
. → Matches any character
\s → Matches any whitespace
\S → Matches any non-whitespace
* → Repeats a character 0 or more times
*? → Repeats a character 0 or more times (non-greedy)
+ → Repeats a character 1 or more times
+? → Repeats a character 1 or more times (non-greedy)
[aeiou] → Matches a single character in the listed set
[^XYZ] → Matches a single character NOT in the listed set
[a-z0-9] → The set of characters can include a range
( → Indicates where string extraction is to start
) → Indicates where string extraction is to end
\ → Escape character
Regular Expression Module
It must be imported at the begining of a program:
import re
- re.search(re_string, string) → similar to find()
- re.findall(re_string, string) → similar to find, returns a list
- re.match(re_string, string)
import re
hand = open('mbox-short.txt')
for line in hand:
line = line.rstrip()
if re.search('^From:', line);
print line
Date
Today as string
import datetime
datetime.date.today().strftime("%B %d, %Y")
String date to date type
from datetime import datetime
fecha_string = '2014-01-15 11:20:05.220'
date = datetime.strptime(fecha_string, '%Y-%m-%d %H:%M:%S.%f')
Files
Counting lines in a file
fhand = open("words.txt")
count = 0
for line in fhand:
count = count + 1
print "line count", count
Reading the whole file
fhand = open("words.txt")
inp = fhand.read() # reads the whole file into memory
print len(inp)# returns the number of characters in a file
print inp # prints the whole file
Searching through a file
fhand= open("mbox-short.txt")
for line in fhand:
# line = line.rstrip()
if line.startswith("From:"):
line = line.rstrip() # better here
print line
File names and paths
fname = raw_input("Enter a file name: ")
if fname[0:2] == "~/": #Check to see if it starts with a ~ and a slash
#If it doesn't start with the ~/, then
#the user could be referring to a valid file
#like "~.py" (I checked: it is possible.)
#notice below replace is valid on Mac OSX only (and not a good approach overall, cause not portable at all)
fname = fname.replace('~',"/Users/"+raw_input("Enter your short user name: "),1)
workingfname = fname.replace("\\",'') #This for proper escaping of a valid folder named '~' as '\~', you can also use './~' as Python automatically escapes for you.
#go back to normal program now
handle = open(workingfname,'r') # . . .
for line in handle:
print line
print "\n"+("That was "+fname+".").center(40)
CSV
import csv
def createCSV(simpleProducts, configProducts, shopName):
'''
Remaps a CSV filce created with tiendalistas magento exporter to
match the Shopify CSV import file
'''
counter = 0
with open(OUTPUT_DIALETCT_TEMPLATE, 'rb') as csvDialectTemplate:
exportDialect = csv.Sniffer().sniff(csvDialectTemplate.read(1024))
# Create file and write headers
with open(OUTPUT_PATH + shopName + '_shopify.csv', 'w') as csvoutFile:
csvWriter = csv.writer(csvoutFile, dialect=exportDialect)
csvWriter.writerow(shopyheader)
counter += 1
# Write lines for simple products
for prod in simpleProducts:
tmp = shopifyCSVitem(prod)
csvWriter.writerow(tmp.productCSVline())
counter += 1
for subP in prod.subProducts:
tmp2 = shopifyCSVitem(subP)
csvWriter.writerow(tmp2.subProductCSVline())
counter += 1
# Write lines for configurable products
for prod in configProducts:
tmp1 = shopifyCSVitem(prod)
csvWriter.writerow(tmp1.productCSVline())
counter += 1
logWrite(logFile, 'Configurable product should be reviewed', tmp1.productCSVline()[0])
for subP in prod.subProducts:
tmp2 = shopifyCSVitem(subP)
csvWriter.writerow(tmp2.productCSVline())
counter += 1
return counter
Run System Commands
Python >= 3.5
def _run_command(command):
log.debug("Command: {}".format(command))
result = subprocess.run(command, shell=True, capture_output=True)
if result.stderr:
raise subprocess.CalledProcessError(
returncode=result.returncode,
cmd=result.args,
stderr=f"{result.stdout}\n{result.stderr}"
)
if result.stdout:
log.debug("Command Result: {}".format(result.stdout.decode('utf-8')))
return result
Class
class MyClass:
__init__(self, arg1, arg2):
#This functionn will be executed every time you instantiate an element of this class
self.var1 = arg1
self.var2 = arg2
def myFunction(self, param1):
self.var1 = self.var1 +param1
Built in attributes:
__dict__ → Dictionary containing the class's namespace
__doc__ → Class documentation string or None if undefined
__name__ → Class name
__module__ → Module name in which the class is defined. This attribute is "__main__" in interactive mode.
__bases__ → A possibly empty tuple containing the base classes in the order of their occurrence
Inheritance
class SubClassName(ParentClass1[, ParentClass2, ...]):
'Optional class documentation string'
# Class code
- issubclass(sub, sup)
- isinstance(obj, Class)
Generic functionality that can be overriden in own classes
__init__(self[, args...]) → Constructor
__del__(self) → Executed when Python's garbage collector destroys an object
__repr__(self) → Evaluable string representation
__str__(self) → Printable string representation
__cmp__(self, x) → Object comparison
__add__(self, other) → To define the + operator behave
Hiding attributes
attributes that start with a __ wont be visible to others
Subclasing builtins
Perfect dict subclass
# has a ton of errors: https://stackoverflow.com/questions/3387691/how-to-perfectly-override-a-dict
class LowerDict(dict):
__slots__ = ()
def _process_args(mapping=(), **kwargs):
if hasattr(mapping, items):
mapping = getattr(mapping, items)()
return ((ensure_lower(k), v) for k, v in chain(mapping, getattr(kwargs, items)()))
def __init__(self, mapping=(), **kwargs):
super(LowerDict, self).__init__(self._process_args(mapping, **kwargs))
def __getitem__(self, k):
return super(LowerDict, self).__getitem__(ensure_lower(k))
def __setitem__(self, k, v):
return super(LowerDict, self).__setitem__(ensure_lower(k), v)
def __delitem__(self, k):
return super(LowerDict, self).__delitem__(ensure_lower(k))
def get(self, k, default=None):
return super(LowerDict, self).get(ensure_lower(k), default)
def setdefault(self, k, default=None):
return super(LowerDict, self).setdefault(ensure_lower(k), default)
def pop(self, k, v=_RaiseKeyError):
if v is _RaiseKeyError:
return super(LowerDict, self).pop(ensure_lower(k))
return super(LowerDict, self).pop(ensure_lower(k), v)
def update(self, mapping=(), **kwargs):
super(LowerDict, self).update(self._process_args(mapping, **kwargs))
def __contains__(self, k):
return super(LowerDict, self).__contains__(ensure_lower(k))
def copy(self): # don't delegate w/ super - dict.copy() -> dict :(
return type(self)(self)
@classmethod
def fromkeys(cls, keys, v=None):
return super(LowerDict, cls).fromkeys((ensure_lower(k) for k in keys), v)
def __repr__(self):
return '{0}({1})'.format(type(self).__name__, super(LowerDict, self).__repr__())
Not so perfect dict like object
from collections.abc import MutableMapping
class TransformedDict(MutableMapping):
"""A dictionary that applies an arbitrary key-altering
function before accessing the keys"""
def __init__(self, *args, **kwargs):
self.store = dict()
self.update(dict(*args, **kwargs)) # use the free update to set keys
def __getitem__(self, key):
return self.store[self._keytransform(key)]
def __setitem__(self, key, value):
self.store[self._keytransform(key)] = value
def __delitem__(self, key):
del self.store[self._keytransform(key)]
def __iter__(self):
return iter(self.store)
def __len__(self):
return len(self.store)
def _keytransform(self, key):
return key
os.system()
To execute a Linux command from Python:
os.system(command) → returns exit status
Database Access
MySQLdb
Table creation
#!/usr/bin/python
import MySQLdb
# Open database connection
db = MySQLdb.connect("DB_HOST","DB_USER","DB_PASSWORD","DB_NAME" )
# prepare a cursor object using cursor() method
cursor = db.cursor()
# Drop table if it already exist using execute() method.
cursor.execute("DROP TABLE IF EXISTS EMPLOYEE")
# Create table as per requirement
sql = """CREATE TABLE EMPLOYEE (
FIRST_NAME CHAR(20) NOT NULL,
LAST_NAME CHAR(20),
AGE INT,
SEX CHAR(1),
INCOME FLOAT )"""
cursor.execute(sql)
INSERT operation
#!/usr/bin/python
import MySQLdb
# Open database connection
db = MySQLdb.connect("DB_HOST","DB_USER","DB_PASSWORD","DB_NAME" )
# prepare a cursor object using cursor() method
cursor = db.cursor()
# Prepare SQL query to INSERT a record into the database.
sql = "INSERT INTO EMPLOYEE(FIRST_NAME, \
LAST_NAME, AGE, SEX, INCOME) \
VALUES ('%s', '%s', '%d', '%c', '%d' )" % \
('Mac', 'Mohan', 20, 'M', 2000)
try:
# Execute the SQL command
cursor.execute(sql)
# Commit your changes in the database
db.commit()
except:
# Rollback in case there is any error
db.rollback()
# disconnect from server
db.close()
Read example Once the query is made you can:
- fetchone()
- fetchall()
- rowcount
#!/usr/bin/python
import MySQLdb
# Open database connection
db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )
# prepare a cursor object using cursor() method
cursor = db.cursor()
# Prepare SQL query to INSERT a record into the database.
sql = "SELECT * FROM EMPLOYEE \
WHERE INCOME > '%d'" % (1000)
try:
# Execute the SQL command
cursor.execute(sql)
# Fetch all the rows in a list of lists.
results = cursor.fetchall()
print "Found ', cursor.rowcount, ' results: '
for row in results:
fname = row[0]
lname = row[1]
age = row[2]
sex = row[3]
income = row[4]
# Now print fetched result
print "fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \
(fname, lname, age, sex, income )
except:
print "Error: unable to fecth data"
# disconnect from server
db.close()
PostgreSQL
Refer to: PostgreSQL
Other
Refer to: Database Interfaces
ssh tunneling
import subprocess
sshcommand = ['ssh', '-o', 'StrictHostKeyChecking=no', '-i', keyFilePath, '-N', '-L', '8888:localhost:3306', 'user@' + Host]
ssh_proc = subprocess.Popen(sshcommand, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
# Do stuff
ssh_proc.terminate()
Multithreading
#!/usr/bin/python
import thread
import time
#Define a function for the thread
def print_time( threadName, delay):
count = 0
while count < 5:
time.sleep(delay)
count += 1
print "%s: %s" % ( threadName, time.ctime(time.time()) )
# Create two threads as follows
try:
thread.start_new_thread( print_time, ("Thread-1", 2, ) )
thread.start_new_thread( print_time, ("Thread-2", 4, ) )
except:
print "Error: unable to start thread"
while 1:
pass
(*) see also threading module:
import threading
Python GUI Programming
- Tkinter: Tkinter is the Python interface to the Tk GUI toolkit shipped with Python. We would look this option in this tutorial.
- wxPython: This is an open-source Python interface for wxWindows http://wxpython.org.
- JPython: JPython is a Python port for Java which gives Python scripts seamless access to Java class libraries on the local machine http://www.jython.org.
Tkinter
#!/usr/bin/python
import Tkinter
top = Tkinter.Tk()
# Code to add widgets will go here...
top.mainloop()
Widgets
- Button The Button widget is used to display buttons in your application.
- Canvas The Canvas widget is used to draw shapes, such as lines, ovals, polygons and rectangles, in your application.
- Checkbutton The Checkbutton widget is used to display a number of options as checkboxes. The user can select multiple options at a time.
- Entry The Entry widget is used to display a single-line text field for accepting values from a user.
- Frame The Frame widget is used as a container widget to organize other widgets.
- Label The Label widget is used to provide a single-line caption for other widgets. It can also contain images.
- Listbox The Listbox widget is used to provide a list of options to a user.
- Menubutton The Menubutton widget is used to display menus in your application.
- Menu The Menu widget is used to provide various commands to a user. These commands are contained inside Menubutton.
- Message The Message widget is used to display multiline text fields for accepting values from a user.
- Radiobutton The Radiobutton widget is used to display a number of options as radio buttons. The user can select only one option at a time.
- Scale The Scale widget is used to provide a slider widget.
- Scrollbar The Scrollbar widget is used to add scrolling capability to various widgets, such as list boxes.
- Text The Text widget is used to display text in multiple lines.
- Toplevel The Toplevel widget is used to provide a separate window container.
- Spinbox The Spinbox widget is a variant of the standard Tkinter Entry widget, which can be used to select from a fixed number of values.
- PanedWindow A PanedWindow is a container widget that may contain any number of panes, arranged horizontally or vertically.
- LabelFrame A labelframe is a simple container widget. Its primary purpose is to act as a spacer or container for complex window layouts.
- tkMessageBox This module is used to display message boxes in your applications.
Standard attributes
- Dimensions
- Colors
- Fonts
- Anchors
- Relief styles
- Bitmaps
- Cursors
Geometry Management
- The pack() Method - This geometry manager organizes widgets in blocks before placing them in the parent widget.
- The grid() Method - This geometry manager organizes widgets in a table-like structure in the parent widget.
- The place() Method -This geometry manager organizes widgets by placing them in a specific position in the parent widget.
For further reference visit: tutorialspoint.com/python/python_gui_programming.htm
Enable auto complete in python interpreter
Create a file in your home directory named: .pythonrc
Content of this file:
import rlcompleter, readline
readline.parse_and_bind('tab:complete')
Set the PYTHONSTARTUP variable in your .bashrc or .bash_profile
echo "export PYTHONSTARTUP=~/.pythonrc" >> .bashrc
Reload your .bashrc or .bash_profile
source ~/.bashrc
To test it import a library, write librariname. and hit tab twice
Delete *.pyc
find . -name "*.pyc" -exec rm -rf {} \;
format hex
Use the format() function with a '02x' format.
>>> format(255, '02x')
'ff'
>>> format(2, '02x')
'02'
The 02 part tells format() to use at least 2 digits and to use zeros to pad it to length, x
means lower-case hexadecimal.
The Format Specification Mini Language also gives you X for uppercase hex output, and you can
prefix the field width with # to include a 0x or 0X prefix (depending on wether you used
x or X as the formatter). Just take into account that you need to adjust the field width
to allow for those extra 2 characters:
>>> format(255, '02X')
'FF'
>>> format(255, '#04x')
'0xff'
>>> format(255, '#04X')
'0XFF'
Command completion
$ nano ~/.pythonrc
# ~/.pythonrc
# enable syntax completion
try:
import readline
except ImportError:
print("Module readline not available.")
else:
import rlcompleter
readline.parse_and_bind("tab: complete")
$ nano ~/.bashrc
export PYTHONSTARTUP=~/.pythonrc
nose debug
nosetests --debug=nose,nose.importer --debug-log=nose_debug <your usual args>
Publish Python Package
Upload a package to pypi. This would make your package available with:
pip install mypackage
With setup.py
nano ~/.pypirc
[distutils]
index-servers =
pypi
pypitest
[pypi]
repository=https://upload.pypi.org/legacy/
username=your_username
password=your_password
[pypitest]
repository=https://testpypi.python.org/pypi
username=your_username
password=your_password
Adjust .pypirc permissions
chmod 600 ~/.pypirc
In your project, create a setup.py
import os
from setuptools import setup, find_packages
# from distutils.core import setup
# allow setup.py to be run from any path
os.chdir(os.path.normpath(os.path.join(os.path.abspath(__file__), os.pardir)))
def here(name):
return os.path.join(
os.path.dirname(os.path.abspath(__file__)),
name)
def read(name, mode='rb', encoding='utf8'):
os.system('pandoc --from=markdown --to=rst --output=README.rst README.md')
if os.path.exists('README.rst'):
long_description = open('README.rst').read()
else:
try:
with open(here(name), mode) as fp:
long_description = fp.read()
except IOError:
return 'Error generating long description: {} File not found'.format(here(name))
return long_description
# Development Status :: 1 - Planning
# Development Status :: 2 - Pre-Alpha
# Development Status :: 3 - Alpha
# Development Status :: 4 - Beta
# Development Status :: 5 - Production/Stable
# Development Status :: 6 - Mature
# Development Status :: 7 - Inactive
license_classifiers = {
'MIT license': 'License :: OSI Approved :: MIT License',
'BSD license': 'License :: OSI Approved :: BSD License',
'ISC license': 'License :: OSI Approved :: ISC License (ISCL)',
'Apache Software License 2.0': 'License :: OSI Approved :: Apache Software License',
'GNU General Public License v3': 'License :: OSI Approved :: GNU General Public License v3 (GPLv3)'
}
setup(
name='CheKnife',
version='v0.0.6b2',
packages=find_packages(),
url='https://git.herrerosolis.com/Misc/CheKnife',
download_url='https://git.herrerosolis.com/Misc/CheKnife/-/archive/v0.0.6b2/CheKnife-v0.0.6b2.tar.gz',
license='MIT license',
author='Rafael Herrero Solis',
author_email='rafahsolis@hotmail.com',
keywords=['CheKnife', 'Swiss', 'Army', 'Knife', 'Swiss Army Knife'],
description='Python Utilities',
long_description=read('README.md'),
test_suite='nose.collector',
tests_require=['nose', 'six'],
install_requires=[
'six>=1.10.0',
'future>=0.16.0',
'pycryptodome>=3.6.1',
'configparser>=3.5.0'
],
classifiers=[
'License :: OSI Approved :: MIT License',
'Development Status :: 3 - Alpha',
'License :: OSI Approved :: Apache Software License',
'Programming Language :: Python :: 3.6',
],
)
nano setup.cfg
[metadata]
description-file = README.md
nano LICENSE
The MIT License
SPDX short identifier: MIT
Copyright <YEAR> <COPYRIGHT HOLDER>
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Test and upload
python setup.py register -r pypitest
python setup.py sdist upload -r pypitest
python setup.py register -r pypi
python setup.py sdist upload -r pypi
With twine
https://packaging.python.org/tutorials/packaging-projects/
Change PyPi
Using PyPi Local Repository
nano ~/.pip/pip.conf
[global]
index-url= http://10.255.0.21/pypi/simple
trusted-host= 10.255.0.21
Using pip behind proxy
sudo pip --proxy http://proxy.hell:3128 install requests
Publish to PyPi
Create the file ~/.pypirc
[distutils]
index-servers =
pypi
pypitest
[pypi]
repository=https://pypi.python.org/pypi
username=
password=
[pypitest]
repository=https://test.pypi.org/legacy
username=
password=
Test
python setup.py register -r pypitest python setup.py sdist upload -r pypitest
Upload
python setup.py register -r pypi python setup.py sdist upload -r pypi
requirements.txt
Platform conditional
psycopg2-binary~=2.9.7; platform_system == "Linux"
psycopg2~=2.9.6; platform_system == "Windows"
AWS boto3 EC2
import boto3
client = boto3.client('ec2', aws_access_key_id="AKI.............Q", aws_secret_access_key="2..........................s", region_name='us-east-1')
ec2_regions = [region['RegionName'] for region in client.describe_regions()['Regions']]
instances = []
for region in ec2_regions:
conn = boto3.resource('ec2', aws_access_key_id="AKIAJBWPORUPPGNSUWXQ", aws_secret_access_key="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", region_name=region)
instances += conn.instances.filter()
i = instances[0]
i.public_dns_name
i.public_ip_address