how to remove letters from a string code example

Example 1: python remove string from string

s = 'ab12abc34ba'
print(s.replace('ab', ''))

Example 2: remove from string python

"Str*ing With Chars I! don't want".replace('!','').replace('*','')

Example 3: 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 4: how to remove letters from string

public extractLetters(String str){
	String result="";
	for(int i= 0; i< str.length; i++){
	    if(Character.isLetter(str.charAt(i))){
	    result+=str.charAt(i);
	  	}
	}