How to pad a string to a fixed length with spaces in Python?

I'm sure this is covered in plenty of places, but I don't know the exact name of the action I'm trying to do so I can't really look it up. I've been reading an official Python book for 30 minutes trying to find out how to do this.

Problem: I need to put a string in a certain length "field".

For example, if the name field was 15 characters long, and my name was John, I would get "John" followed by 11 spaces to create the 15 character field.

I need this to work for any string put in for the variable "name".

I know it will likely be some form of formatting, but I can't find the exact way to do this. Help would be appreciated.

Solution 1:

This is super simple with format:

>>> a = "John"
>>> "{:<15}".format(a)
'John           '

Solution 2:

You can use the ljust method on strings.

>>> name = 'John'
>>> name.ljust(15)
'John           '

Note that if the name is longer than 15 characters, ljust won't truncate it. If you want to end up with exactly 15 characters, you can slice the resulting string:

>>> name.ljust(15)[:15]

Solution 3:

If you have python version 3.6 or higher you can use f strings

>>> string = "John"
>>> f"{string:<15}"
'John           '

Or if you'd like it to the left

>>> f"{string:>15}"
'          John'

Centered

>>> f"{string:^15}"
'     John      '

For more variations, feel free to check out the docs: https://docs.python.org/3/library/string.html#format-string-syntax