How to check a number for the possible presence of letters?

Question

PHP

How can I check the number, let's say 1234 for the presence of letters, if 1234 then true, if 12F4 then fall. Tell me please...

Answer 1

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Answer 2

function a($str) {
 if(is_numeric($str)) {
  return true;
 }
 return false;
}