how to remove all letters in a sting python code example

Example 1: python remove letters from string

string = "abc123"
# Method 1
''.join(char for char in string if char.isdigit())

#Method 2
import re
re.sub("[^0-9]", "", string)

Example 2: how to remove all characters from a string in python

s = 'abc12321cba'

print(s.replace('a', ''))