Lists are one of the 4 data types in Python used to store collections of data.

['John','Peter','Debora','Charles']

Getting values with indexes

>>> furniture=['table','chair','rack','shelf']>>> furniture[0]# 'table'>>> furniture[1]# 'chair'>>> furniture[2]# 'rack'>>> furniture[3]# 'shelf'

Negative indexes

>>> furniture=['table','chair','rack','shelf']>>> furniture[-1]# 'shelf'>>> furniture[-3]# 'chair'>>>f'The{furniture[-1]} is bigger than the{furniture[-3]}'# 'The shelf is bigger than the chair'

Getting sublists with Slices

>>> furniture=['table','chair','rack','shelf']>>> furniture[0:4]# ['table', 'chair', 'rack', 'shelf']>>> furniture[1:3]# ['chair', 'rack']>>> furniture[0:-1]# ['table', 'chair', 'rack']>>> furniture[:2]# ['table', 'chair']>>> furniture[1:]# ['chair', 'rack', 'shelf']>>> furniture[:]# ['table', 'chair', 'rack', 'shelf']

Slicing the complete list will perform a copy:

>>> spam2= spam[:]# ['cat', 'bat', 'rat', 'elephant']>>> spam.append('dog')>>> spam# ['cat', 'bat', 'rat', 'elephant', 'dog']>>> spam2# ['cat', 'bat', 'rat', 'elephant']

Getting a list length with len()

>>> furniture=['table','chair','rack','shelf']>>>len(furniture)# 4

Changing values with indexes

>>> furniture=['table','chair','rack','shelf']>>> furniture[0]='desk'>>> furniture# ['desk', 'chair', 'rack', 'shelf']>>> furniture[2]= furniture[1]>>> furniture# ['desk', 'chair', 'chair', 'shelf']>>> furniture[-1]='bed'>>> furniture# ['desk', 'chair', 'chair', 'bed']

Concatenation and Replication

>>>[1,2,3]+['A','B','C']# [1, 2, 3, 'A', 'B', 'C']>>>['X','Y','Z']*3# ['X', 'Y', 'Z', 'X', 'Y', 'Z', 'X', 'Y', 'Z']>>> my_list=[1,2,3]>>> my_list= my_list+['A','B','C']>>> my_list# [1, 2, 3, 'A', 'B', 'C']

Using for loops with Lists

>>> furniture=['table','chair','rack','shelf']>>>for itemin furniture:...print(item)# table# chair# rack# shelf

Getting the index in a loop with enumerate()

>>> furniture=['table','chair','rack','shelf']>>>for index, iteminenumerate(furniture):...print(f'index:{index} - item:{item}')# index: 0 - item: table# index: 1 - item: chair# index: 2 - item: rack# index: 3 - item: shelf

Loop in Multiple Lists with zip()

>>> furniture=['table','chair','rack','shelf']>>> price=[100,50,80,40]>>>for item, amountinzip(furniture, price):...print(f'The{item} costs ${amount}')# The table costs $100# The chair costs $50# The rack costs $80# The shelf costs $40

The in and not in operators

>>>'rack'in['table','chair','rack','shelf']# True>>>'bed'in['table','chair','rack','shelf']# False>>>'bed'notin furniture# True>>>'rack'notin furniture# False

The Multiple Assignment Trick

The multiple assignment trick is a shortcut that lets you assign multiple variables with the values in a list in one line of code. So instead of doing this:

>>> furniture=['table','chair','rack','shelf']>>> table= furniture[0]>>> chair= furniture[1]>>> rack= furniture[2]>>> shelf= furniture[3]

You could type this line of code:

>>> furniture=['table','chair','rack','shelf']>>> table, chair, rack, shelf= furniture>>> table# 'table'>>> chair# 'chair'>>> rack# 'rack'>>> shelf# 'shelf'

The multiple assignment trick can also be used to swap the values in two variables:

>>> a, b='table','chair'>>> a, b= b, a>>>print(a)# chair>>>print(b)# table

The index Method

Theindex method allows you to find the index of a value by passing its name:

>>> furniture=['table','chair','rack','shelf']>>> furniture.index('chair')# 1

Adding Values

append()

append adds an element to the end of alist:

>>> furniture=['table','chair','rack','shelf']>>> furniture.append('bed')>>> furniture# ['table', 'chair', 'rack', 'shelf', 'bed']

insert()

insert adds an element to alist at a given position:

>>> furniture=['table','chair','rack','shelf']>>> furniture.insert(1,'bed')>>> furniture# ['table', 'bed', 'chair', 'rack', 'shelf']

Removing Values

del()

del removes an item using the index:

>>> furniture=['table','chair','rack','shelf']>>>del furniture[2]>>> furniture# ['table', 'chair', 'shelf']>>>del furniture[2]>>> furniture# ['table', 'chair']

remove()

remove removes an item with using actual value of it:

>>> furniture=['table','chair','rack','shelf']>>> furniture.remove('chair')>>> furniture# ['table', 'rack', 'shelf']

pop()

By default,pop will remove and return the last item of the list. You can also pass the index of the element as an optional parameter:

>>> animals=['cat','bat','rat','elephant']>>> animals.pop()'elephant'>>> animals['cat','bat','rat']>>> animals.pop(0)'cat'>>> animals['bat','rat']

Sorting values with sort()

>>> numbers=[2,5,3.14,1,-7]>>> numbers.sort()>>> numbers# [-7, 1, 2, 3.14, 5]furniture=['table','chair','rack','shelf']furniture.sort()furniture# ['chair', 'rack', 'shelf', 'table']

You can also passTrue for thereverse keyword argument to havesort() sort the values in reverse order:

>>> furniture.sort(reverse=True)>>> furniture# ['table', 'shelf', 'rack', 'chair']

If you need to sort the values in regular alphabetical order, passstr.lower for the key keyword argument in the sort() method call:

>>> letters=['a','z','A','Z']>>> letters.sort(key=str.lower)>>> letters# ['a', 'A', 'z', 'Z']

You can use the built-in functionsorted to return a new list:

>>> furniture=['table','chair','rack','shelf']>>>sorted(furniture)# ['chair', 'rack', 'shelf', 'table']

The Tuple data type