php string contains only numbers code example

Example 1: 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.

Example 2: how to check if PHP variable contains non-numbers?

if ( is_numeric($_POST['foo']) ) {
    $foo = $_POST['foo'];
} else {
    // Error
}

Example 3: php check if string contains number

if (preg_match('/[A-Za-z]/', $myString) && preg_match('/[0-9]/', $myString))
{
    echo 'Contains at least one letter and one number';
}