The list is the most flexible container data type in Python, it represents an ordered sequence of elements.

Some features of lists are outlined below:

  • Lists can contain any type of data including strings, integers, floats, dictionaries, etc
  • Lists are ordered, meaning they keep track of the order of elements
  • Lists are mutable, meaning they can be changed and manipulated.
  • Lists can be indexed, meaning you can access individual elements in the list
  • A list can contain other lists.

Create a list using square brackets 

A list is represented using square brackets in which coma-separated elements are placed inside the brackets. We can use this notation to initialize a list.

 #create an empty list

empty_list = []

#create a list of integers
integer_list = [1, 2, 3, 4]

#create a list of strings
string_list = ['Python', 'Java', 'C++']

#create a list of lists
my_list = [[1, 2], [3, 4], [5, 6]]

Create a list using the list() Function

The builtin list() function is a constructor  that takes an iterable object(tuple, set, string, etc) as an argument and constructs a list using the elements of the iterable. 

list(iterable = None)

 If an iterable is not given, ths function simply creates an empty list.

#create an empty list
empty_list = list()

#create a list from a tuple
my_tuple = (1, 2, 3, 4)
integer_list = list(my_tuple)

#create a list from a string
my_string = "ABCD"
my_list = list(my_string)

Create a list using list comprehension

List comprehension is a type of syntax in which expressions are used to create a list from existing iterables. It efficiently combines the features   of for loops and list literals. 

mylist = [<expression> for <item> in <iterable>]

The results of the expression are added to the list during each iteration. The expression can be any valid single python expression.

#create a list of zeroes
list1 = [0 for i in range(10)]

#create a list with the elements of the iterable
list2 = [i for i in (1, 2, 3, 4, 5)]

#create a list of odd numbers
list3 = [n for n in range(20) if n%2]

You can check on list comprehension to see more on its syntax and usage.

Create a list using * operator

We can use the repetition operation with an asterisk(*) operator to create a new list containing a repeating sequence of elements of a given list.

[obj] * n

The n argument is an integer specifying the  number of times to repeat the original list.

#creat a list of zeroes
list1 = [0] * 10

#create a list of repeating tuples
list2 = [(1, 2)] * 5