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Python Basics - Lists, Tuples and Dictionaries Cheat Sheet (DRAFT) by

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

Lists and Tuples Syntax

L = [1, 2, 3, 4, 5]
Lists are created with [ ]
 
T = (10, 20, 30, 40, 50)
Tuples are created with ( )
 
L[0]
Returns 1st element of L (1)
 
T[0]
Returns 1st element of T (10)
 
L[1:4]
Returns 2nd to 4th element of L ([2, 3, 4])
 
T[1:4]
Returns 2nd to 4th element of T ((20, 30, 40))
 
L[0:-1:2]
Returns 1st to 2nd last element of L skipping one at a time ([1, 3])
 
T[0:-1:2]
Returns 1st to 2nd last element of L skipping one at a time ((10, 30))
 
L[1] = 22
Assigns 22 to 2nd element of L (L == [1, 22, 3, 4, 5])
 
T[1] = 22
ERROR: You can't assing anything to tuples
 
L[0:2] = [11, 22]
Assigns 11 and 22 to 1st and 2nd element of L respec­tively (L == [11, 22, 3, 4, 5])
Lists are mutable and Tuples are NOT mutable

Lists - Methods

a = ['a', 'b', 'c']
 
b = [1, 3, 2]
 
a + b
Returns a concat­enated with b (['a', 'b', 'c', 1, 3, 2])
 
'c' in a
Returns True if 'c' is in the list a and False otherwise (True)
 
len(a)
Returns the number of elements in a (3)
 
a.appe­nd('d')
Appends 'd' to the end of the list a (a == ['a', 'b', 'c', 'd'])
 
a.extend(['d', 'e', 'f'])
Appends every element of the iterable to the end of a (a == ['a', 'b', 'c', 'd', 'e', 'f'])
 
a.inse­rt(1, 'd')
Inserts 'd' to index 1 of a (a == ['a', 'd', 'b', 'c'])
 
a.pop()
Returns the last element of the list and deletes it from the list. ('c')
 
a.pop(1)
Returns 2nd element of a and removes it from the list ('b')
 
a.remo­ve('b')
Removes first occurrence of 'b' in a (a == ['a', 'c'])
 
a.clear()
Clears the list entirely (a == [])
 
a.inde­x('b')
Returns the index of the first occurrence of 'b' (1)
 
a.coun­t('b')
Returns the number of occurr­ences of 'b' in a (1)
 
b.sort()
Returns a sorted version of b ([1, 2, 3])
 
a.reve­rse()
Reverses the list a (['c', 'b', 'a'])
 
a.copy()
Returns a copy of a
The copy() method returns a list identical to the original, but with a different ID. It means that they are allocated in different places of memory.

Tuple - Methods

t1 = ('a', 'b', 'c')
 
t2 = (1, 2, 3)
 
t1 + t2
Returns a concat­enated version of t1 and t2
 
2 in t2
Returns True if 2 is in t2 and False otherwise (True)
 
len(t1)
Returns the number of elements in t1 (3)
 
t2.cou­nt(2)
Returns the number of occurr­ences of 2 in t2 (1)
 
t2.ind­ex(1)
Returns the index of the 1st occurrence of 1 (0)

Lists - Loops 1

a = ['one' , 'two', 'three']

for i in a:
    print(i)
one
two
three

Lists - Loops 2

a = ['one' , 'two', 'three']

for i in range(len(a)):
    print(f"a[{i}] == {a[i]}")
a[0] == one
a[1] == two
a[2] == three