Prepend the same string to all items in a list

Have done some searching through Stack Exchange answered questions but have been unable to find what I am looking for.

Given the following list:

a = [1, 2, 3, 4]

How would I create:

a = ['hello1', 'hello2', 'hello3', 'hello4']

Thanks!

Answer

Use a list comprehension:

[f'hello{i}' for i in a]

A list comprehension lets you apply an expression to each element in a sequence. Here that expression is a formatted string literal, incorporating i into a string starting with hello.

Demo:

>>> a = [1,2,3,4]
>>> [f'hello{i}' for i in a]
['hello1', 'hello2', 'hello3', 'hello4']