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Python 3 Cheat Sheet (DRAFT) by

Python easy Cheat sheet.

This is a draft cheat sheet. It is a work in progress and is not finished yet.

File operations

f = open(path)
open file
 
f.read()
read file
 
f.read­line()
read line from file
 
f.read­lines()
return list of lines of file
 
f.write(s)
write s to file
 
f.close()
close file
 
with open(path) as name: 
  statements
open and after statements close file

Logic and Math Operators

x + y
addition
 
x - y
subtra­ction
 
x * y
multip­lic­ation
 
x / y
division
 
x // y
floor
 
x ** y
exponent
 
x % y
modulo
 
x == y
equal
 
x != y
not equal
 
x > y
greater than
 
x >= y
greater than or equal
 
x < y
less than
 
x <= y
less than or equal

Converting Data Types

str(num)
number to string
 
str(txt, encoding)
encoded bytes to string
 
int("st­r", base = 10)
number string to integer
 
hex(int)
integer to hex string
 
bin(int)
integer to binary string
 
int(float)
float to integer
 
float(int or str)
integer / string to float
 
ord(str)
string to ASCII
 
chr(int)
integer to ASCII
 

Base Functions

int(), float(), str(), bool() ...
type casting
 
len(data)
return length of data
 
min(va­lue), 
 max(value)
minimum
maximum
 
pow(x, y, [z])
x to the power y [mod z]
 
range(­start, stop, [step])
range of
 
input(), 
 print()
console input
console output
 
filter­(fu­nction, iterable)
filter iterable
 
id(object)
unique object ID
 
map(fu­nction, iterable)
map function onto iterable
 
round(n, [x])
round n to x decimal places
[ _ ] optional argument

Module Import

import module as name
 
from module import submodule as name

Exception Handling

try:
  statements 
 except [exception type]: 
 statements
finally:
 statements

Dictio­naries

d = {}
create dictionary
 
d = { key : val }
create dictionary with values
 
d[key] = val
assign a value
 
d[key], 
 d.get(key)
access value at key
 
d.keys()
iterable view of keys
 
d.values()
iterable view of values
 
d.items()
iterable view of (key, value) tuples
 
d.clear()
clear dictionary
 
key in d
determine if key exists

Lists

n = []
create list
 
n[index] = val
assign value at index
 
n[index]
access value at index
 
n.appe­nd(val)
add to list
 
n.inse­rt(­pos­ition, val)
insert into list
 
n.coun­t(val)
count occurness
 
n.remo­ve(val)
remove item
 
n.pop(val)
remove an return item
 
n.reve­rse()
reverse n
 
n.sort()
sort n

Slicing and Indexing

x[star­t:s­top­:step]
x = [4, 8, 9, 3, 0]
 
x[0]
4
 
x[-1]
0
 
x[:3]
[4, 8, 9]
 
x[3:]
[3, 0]
 
x[:-2]
[4, 8, 9]
 
x[::2]
[4, 9, 0]
 
x[::-1]
[0, 3, 9, 8, 4]