php check if string contains only letters code example

Example 1: php check if string contains word

$myString = 'Hello Bob how are you?';
if (strpos($myString, 'Bob') !== false) {
    echo "My string contains Bob";
}

Example 2: check value contains numbers or letters php

ctype_digit(string text);

Parameter Used:
The ctype_digit() function in PHP accepts only one parameter.

text : Its mandatory parameter which specifies the tested string.

Return Values:
It returns TRUE if all characters of the string are numeric otherwise 
  return FALSE.
  
Input  : '789495001'
Output : TRUE
Explanation : All digits, return True

Input  : 'adc123' or '789.0877'
Output : FALSE
Explanation: String contains number and string or floating point, 
return false.