@ -3,6 +3,7 @@ Comprehensive Python Cheatsheet
Main
----
```python
@ -72,6 +73,7 @@ Counter({'blue': 3, 'red': 2, 'yellow': 1})
'blue'
```
Set
---
```python
@ -96,6 +98,7 @@ Set
< frozenset > = frozenset(< collection > )
```
Range
-----
```python
@ -105,6 +108,7 @@ range(from_inclusive, to_exclusive, step_size)
range(from_inclusive, to_exclusive, -step_size)
```
Enumerate
---------
```python
@ -112,6 +116,7 @@ for i, <el> in enumerate(<collection> [, i_start]):
...
```
Named Tuple
-----------
```python
@ -126,6 +131,7 @@ Point(x=1, y=2)
('x', 'y')
```
Iterator
--------
#### Skips first element:
@ -285,9 +291,9 @@ import textwrap
textwrap.wrap(text, width)
```
Numbers
-------
### Basic Functions
```python
round(< num > [, ndigits])
@ -332,6 +338,7 @@ import random
random.shuffle(< list > )
```
Datetime
--------
```python
@ -346,6 +353,7 @@ now.strftime('%Y%m%d%H%M%S') # '20180315002834'
< datetime > = datetime.strptime('2015-05-12 00:39', '%Y-%m-%d %H:%M')
```
Arguments
---------
**"*" is the splat operator, that takes a list as input, and expands it into actual positional arguments in the function call:**
@ -384,6 +392,7 @@ def add(*a):
[2, 3]
```
Inline
------
### Lambda
@ -446,6 +455,7 @@ Cutlery = Enum('Cutlery', {'knife': 1, 'fork': 2, 'spoon': 3})
Creature = type('Creature', (), {'position': Point(0, 0), 'direction': Direction.n})
```
Closure
-------
```python
@ -463,6 +473,7 @@ from functools import partial
partial(< function > , < arg_1 > [, < arg_2 > , ...])
```
Decorator
---------
```python
@ -504,14 +515,23 @@ class <name>:
return cls.__name__
```
#### Constructor overloading:
### Constructor Overloading
```python
class < name > :
def __init__ (self, a=None):
self.a = a
```
### Enum
### Copy
```python
import copy
< object > = copy.copy(< object > )
< object > = copy.deepcopy(< object > )
```
Enum
----
```python
from enum import Enum, auto
class < enum_name > (Enum):
@ -543,7 +563,7 @@ list(a.name for a in <enum>) # == ['<member_name_1>', '<member_name_2>', ...]
random.choice(list(< enum > )) # == random < member >
```
#### Inline:
### Inline
```python
Cutlery = Enum('Cutlery', ['knife', 'fork', 'spoon'])
Cutlery = Enum('Cutlery', 'knife fork spoon')
@ -558,17 +578,9 @@ LogicOp = Enum('LogicOp', {'AND': (auto(), lambda l, r: l and r),
'OR' : (auto(), lambda l, r: l or r)}
```
### Copy
```python
import copy
< object > = copy.copy(< object > )
< object > = copy.deepcopy(< object > )
```
System
------
### Arguments
```python
import sys
@ -615,7 +627,6 @@ b'.\n..\nfile1.txt\nfile2.txt\n'
0
```
### Input
```python
filename = input('Enter a file name: ')
@ -630,6 +641,7 @@ while True:
break
```
JSON
----
```python
@ -662,6 +674,7 @@ def write_to_json_file(filename, an_object):
json.dump(an_object, file, ensure_ascii=False, indent=2)
```
SQLite
------
```python
@ -683,6 +696,7 @@ db.execute(<query>)
db.commit()
```
Exceptions
----------
```python
@ -701,6 +715,7 @@ while True:
raise IOError("input/output error")
```
Bytes
-----
**Bytes objects are immutable sequences of single bytes.**
@ -738,6 +753,7 @@ def write_bytes(filename, bytes):
< Bytes > = b''.join(< list_of_Bytes > )
```
Struct
------
**This module performs conversions between Python values and C structs represented as Python Bytes objects:**
@ -768,6 +784,7 @@ b'\x00\x01\x00\x02\x00\x00\x00\x03'
* `f` - float
* `d` - double
Hashlib
-------
```python
@ -775,6 +792,7 @@ Hashlib
'33d0eba106da4d3ebca17fcd3f4c3d77'
```
Threading
---------
```python
@ -797,6 +815,7 @@ lock.acquire()
lock.release()
```
Itertools
---------
**Every function returns a generator and can accept any collection. If you want to print an output of generator, as in examples, you need to pass it to the list() function.**
@ -806,7 +825,6 @@ from itertools import *
```
### Combinatoric iterators
```python
>>> combinations('abc', 2)
[('a', 'b'), ('a', 'c'), ('b', 'c')]
@ -822,7 +840,6 @@ from itertools import *
```
### Infinite iterators
```python
>>> i = count(5, 2)
>>> next(i), next(i), next(i)
@ -837,7 +854,6 @@ from itertools import *
```
### Iterators
```python
>>> chain([1, 2], range(3, 5))
[1, 2, 3, 4]
@ -912,7 +928,6 @@ type(<class_name>, <parents_tuple>, <attributes_dict>)
>>> z = Z()
```
### MetaClass
#### Class that creates class:
```python
@ -980,6 +995,7 @@ def eval_(node):
-5.0
```
Coroutine
---------
* **Similar to Generator, but Generator pulls data through the pipe with iteration, while Coroutine pushes data into the pipeline with send().**
@ -1037,6 +1053,7 @@ pyplot.show()
pyplot.savefig(< filename > , transparent=True)
```
Table
-----
#### Prints CSV file as ASCII table:
@ -1050,6 +1067,7 @@ with open(<filename>, newline='') as csv_file:
print(tabulate(reader, headers))
```
Curses
------
```python
@ -1072,6 +1090,7 @@ def get_border(screen):
return P(width - 1, height - 1)
```
Image
-----
#### Creates PNG image of greyscale gradient:
@ -1091,6 +1110,7 @@ img.save('out.png')
* `RGBA` - 4x8-bit pixels, true color with transparency mask
* `HSV` - 3x8-bit pixels, Hue, Saturation, Value color space
Audio
-----
#### Saves list of floats with values between 0 and 1 to a WAV file:
@ -1105,6 +1125,7 @@ wf.writeframes(b''.join(frames))
wf.close()
```
UrlLib
------
### Translate special characters
@ -1113,6 +1134,7 @@ import urllib.parse
< str > = urllib.parse.quote_plus(< str > )
```
Web
---
```python
@ -1159,6 +1181,7 @@ def p_handler(sport):
return json.dumps([home_odds, away_odds])
```
Profile
-------
#### Basic:
@ -1199,6 +1222,7 @@ def get_datetime_string(a_datetime):
return a_datetime.strftime('%Y%m%d%H%M%S')
```
Progress Bar
------------
### Basic:
@ -1260,6 +1284,7 @@ for i in range(STEPS):
bar.finish()
```
Basic Script Template
---------------------
```python
@ -1293,6 +1318,3 @@ def read_file(filename):
if __name__ == '__main__':
main()
```
Jure Šorn
5 years ago