How do I convert a string to a number in PHP?

Question

I want to convert these types of values, '3', '2.34', '0.234343', etc. to a number. In JavaScript we can use Number(), but is there any similar method available in PHP?

Input             Output
'2'               2
'2.34'            2.34
'0.3454545'       0.3454545

Answer 1

You don't typically need to do this, since PHP will coerce the type for you in most circumstances. For situations where you do want to explicitly convert the type, cast it:

$num = "3.14";
$int = (int)$num;
$float = (float)$num;

Answer 2

There are a few ways to do so:

1. Cast the strings to numeric primitive data types:

   $num = (int) "10";
   $num = (double) "10.12"; // same as (float) "10.12";
   

2. Perform math operations on the strings:

   $num = "10" + 1;
   $num = floor("10.1");
   

3. Use intval() or floatval():

   $num = intval("10");
   $num = floatval("10.1");
   

4. Use settype().

Answer 3

To avoid problems try intval($var). Some examples:

<?php
echo intval(42);                      // 42
echo intval(4.2);                     // 4
echo intval('42');                    // 42
echo intval('+42');                   // 42
echo intval('-42');                   // -42
echo intval(042);                     // 34 (octal as starts with zero)
echo intval('042');                   // 42
echo intval(1e10);                    // 1410065408
echo intval('1e10');                  // 1
echo intval(0x1A);                    // 26 (hex as starts with 0x)
echo intval(42000000);                // 42000000
echo intval(420000000000000000000);   // 0
echo intval('420000000000000000000'); // 2147483647
echo intval(42, 8);                   // 42
echo intval('42', 8);                 // 34
echo intval(array());                 // 0
echo intval(array('foo', 'bar'));     // 1
?>