Python How to Convert List of Integers to Strings

You can convert a list of integers to strings in Python by using a list comprehension like [str(i) for i in int_list] which creates a new list with each integer converted to a string.

Examples

Input[1, 2, 3]

Output['1', '2', '3']

Input[10, 0, -5]

Output['10', '0', '-5']

Input[]

Output[]

How to Think About It

To convert each integer in a list to a string, think of going through the list one by one and changing each number into its text form. This is like writing down numbers as words on paper. Using a list comprehension helps do this quickly and clearly.

Algorithm

1

Get the input list of integers.

2

Create a new empty list to hold strings.

3

For each integer in the input list, convert it to a string.

4

Add the string to the new list.

5

Return the new list of strings.

Code

python

int_list = [1, 2, 3, 4]
str_list = [str(i) for i in int_list]
print(str_list)

Output

['1', '2', '3', '4']

Dry Run

Let's trace the list [1, 2, 3] through the code

1

Start with input list

int_list = [1, 2, 3]

2

Convert each integer to string

str_list = ['1', '2', '3']

3

Print the result

Output: ['1', '2', '3']

Integer	String
1	'1'
2	'2'
3	'3'

Why This Works

Step 1: List comprehension

The list comprehension [str(i) for i in int_list] loops over each integer i in the list.

Step 2: Convert integer to string

Each integer i is converted to a string using the str() function.

Step 3: Create new list

All converted strings are collected into a new list which is returned.

Alternative Approaches

Using map() function

python

int_list = [1, 2, 3]
str_list = list(map(str, int_list))
print(str_list)

This uses the built-in <code>map</code> to apply <code>str</code> to each item, which is concise and readable.

Using a for loop

python

int_list = [1, 2, 3]
str_list = []
for i in int_list:
    str_list.append(str(i))
print(str_list)

This is more verbose but clear for beginners to understand the step-by-step process.

Complexity: O(n) time, O(n) space

Time Complexity

The code loops through each of the n integers once, converting each to a string, so time is O(n).

Space Complexity

A new list of strings is created with the same length as the input, so space is O(n).

Which Approach is Fastest?

List comprehension and map() have similar performance; for loops are slightly slower but clearer for beginners.

Approach	Time	Space	Best For
List comprehension	O(n)	O(n)	Concise and readable code
map() function	O(n)	O(n)	Functional style, concise
For loop	O(n)	O(n)	Step-by-step clarity for beginners