PHP "is_numeric" accepts "E" as a number

Question

I noticed PHP is_numeric() accepts "E" as a number. I have a string: "88205052E00" and I want the result to be: NOT numeric.

Here is the code which I tested.

<?php

$notnumber = '88205052E00';

if(is_numeric($notnumber)) {
    echo $notnumber . ' is a number';
} else {
    echo $notnumber . ' is NOT a number';
}

?>

The Code above gives result:

88205052E00 is a number

How can I get the result to be: 88205052E00 is NOT a number?

Answer 1

I will keep the answer incase it helps but as pointed out there are shortcomings with ctype_digit in that it does not like - or ..

More likely then you want to use ctype_digit which checks if all of the characters in the provided string, text, are numerical.

Where as is_numeric — Finds whether a variable is a number or a numeric string

<?php

$s = "88205052E00";

if(ctype_digit($s)){
    echo "Yes";
} else {
    echo "No";
}

returns no.

Answer 2

Just use a regular expression:

<?php
if (preg_match("/^\-?[0-9]*\.?[0-9]+\z/", $notnumber)) {
    echo "$notnumber is numeric\n";
} else {
    echo "$notnumber is not numeric\n";
}

Results:

   1234 is numeric
1234E56 is not numeric
  -1234 is numeric
  .1234 is numeric
 -.1234 is numeric
 -12.34 is numeric