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Python Toolbox Cheat Sheet (DRAFT) by

Python Cheatsheet for the UvA B&C Toolbox course

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

Data Types

Text Type
str; str()
'I'm a string'
Numeric Types
int; int()
10
 
float; float()
10.3
Boolean Type
bool
True/False
Sequence Types
list; list()
[1, 2, 'a', 'b']
 
tuple; tuple()
(1, 2, 3)
 
range
range(4)
Set Type
set; set()
{1, 2, 3}
Mapping Type
dict; dict()
{1:'a', 2:'b', 3:'c'}

Booleans

Booleans as Numbers
True==1
False==0
Comparison Operators
a==b
is a equal to b?
a!=b
is a different than b?
a<b
is a less than b?
a<=b
is a less than or equal to b?
a>b
is a greater than b?
a>=b
is a greater than or equal to b?
Membership and Identity Operators
a in b
is a in b?
a is b
are a and b the same object?
a not in b
is a not in b?
a is not b
are a and b different objects?
Boolean Operators
not
returns False if operand is True, True otherwise
and
returns True if Both operands are True, False otherwise
or
returns False if both operands are False, True otherwise
^ (xor)
returns False if both or neither operands are False, True otherwise

Operator Precedence

1.
()
Parent­heses are evaluated first
2.
**
Exponent
3.
+, -
unary + and - signs (e.g., -x)
4.
*, /, //, %
multip­lic­ation, division, floor division, and modulo
5.
+, -
Addition, subtra­ction
6.
^
Bitwise XOR
7.
in, not in, is, is not, <, <=, >, >=, !=, ==
Compar­ison, identity, and membership operators
8.
not
logical NOT
9.
and
Logical AND
10.
or
logical OR
 

Print Function

print('a', 'b', sep='*')
a*b

Decision Structure

if n == 0:
 	print("n is zero")
elif n > 0:
 	print("n is strictly positive")
else: # n < 0
 	print("n is strictly negative")

Repetition Structures

n = 0
while n < 4
 	print(n)
 	n += 1
print("n =", n)
# output is: 0 | 1 | 2 | 3 | n = 4

for i in range(4):
 	print(i)
print("i =", i)
# output is: 0 | 1 | 2 | 3 | i = 3

Exceptions

try:
Built-in Exceptions
 
 	# run this code
FileNo­tFo­und­Error
 
except NameOf­Err­orT­ype1:
IndexError
 
 	# handle error type 2
KeyError
 
except NameOf­Err­orT­ype2:
Module­Not­Fou­ndError
 
 	# handle error type 2
NameError
 
except:
Syntax­Error
 
 	# handle any other error
TypeError
 
else:
ValueError
 
 	# run this code if no error
ZeroDi­vis­ion­Error
 
finally:
 
 	# always run this code

NumPy

import numpy as np
Creating arrays
np.arr­ay(­[1,­2,3])
Convert python list to NumPy array
np.ara­nge­(1,5)
Return sequence from start (incl.) to end (excl.)
np.ara­nge­(1,5,2)
Return stepped sequence from start (incl.) to end (excl.)
np.rep­eat­([1­,3,­6],3)
Repeat values n times: [1,1,1­,3,...]
np.til­e([­1,3­,6],3)
Repeat values n times: [1,3,6­,1,...]
Math functions and methods
All functions take an array as the input