How to convert string number to int and avoid the string text before convert

I would like to create the check condition string is string number or not so, how I can do in python

x = "String"  y = "12"    if x is string:     print("this is string")  if y is string:     print("this is not string")  

https://stackoverflow.com/questions/65433116/how-to-convert-string-number-to-int-and-avoid-the-string-text-before-convert December 24, 2020 at 10:01AM