how to check if PHP variable contains non-numbers?

Question

I just want to know the method to check a PHP variable for any non-numbers and if it also detects spaces between characters? Need to make sure nothing weird gets put into my form fields. Thanks in advance.

Answer 1

This will return true if there are non-numbers in the string. It detects letters, spaces, tabs, new lines, whatever isn't numbers.

preg_match('#[^0-9]#',$variable)

Answer 2

You can use is_numeric() :

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

This will check that the value is numerical, so it may contain something else than digits:

12
-12
12.1

But this will ensure that the value is a valid number.

Answer 3

Cast and compare:

function string_contain_number($val)
{
     return ($val + 0 == $val) ? true : false;
}

Answer 4

if(!ctype_digit($string))
    echo 'The string contains some non-digit'

Answer 5

You can use ctype_digit

eg:

if (!ctype_digit($myString)) {
    echo "Contains non-numbers.";
}

Answer 6

This will check whether the input value is numeric or not. Hope this helps

if(!preg_match('#[^0-9]#',$value))
{
    echo "Value is numeric";
}
else
{
    echo "Value not numeric";
}