How to change variable to number in php?

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;

answered Dec 16, 2011 at 4:13

deceze♦deceze

497k81 gold badges719 silver badges867 bronze badges

10

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().

answered Dec 16, 2011 at 4:12

fardjadfardjad

19.5k6 gold badges50 silver badges67 bronze badges

9

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

SharpC

6,4284 gold badges43 silver badges39 bronze badges

answered Jun 2, 2014 at 13:28

gopecagopeca

1,45311 silver badges12 bronze badges

4

In whatever (loosely-typed) language you can always cast a string to a number by adding a zero to it.

However, there is very little sense in this as PHP will do it automatically at the time of using this variable, and it will be cast to a string anyway at the time of output.

Note that you may wish to keep dotted numbers as strings, because after casting to float it may be changed unpredictably, due to float numbers' nature.

answered Dec 16, 2011 at 4:52

Your Common SenseYour Common Sense

156k39 gold badges208 silver badges331 bronze badges

9

Instead of having to choose whether to convert the string to int or float, you can simply add a 0 to it, and PHP will automatically convert the result to a numeric type.

// Being sure the string is actually a number
if (is_numeric($string))
    $number = $string + 0;
else // Let the number be 0 if the string is not a number
    $number = 0;

answered Jun 3, 2015 at 9:35

webNeatwebNeat

2,6481 gold badge18 silver badges22 bronze badges

1

Yes, there is a similar method in PHP, but it is so little known that you will rarely hear about it. It is an arithmetic operator called "identity", as described here:

Aritmetic Operators

To convert a numeric string to a number, do as follows:

$a = +$a;

answered May 10, 2018 at 18:31

5

If you want get a float for $value = '0.4', but int for $value = '4', you can write:

$number = ($value == (int) $value) ? (int) $value : (float) $value;

It is little bit dirty, but it works.

answered Sep 15, 2014 at 4:44

9

You can use:

(int)(your value);

Or you can use:

intval(string)

answered Dec 16, 2011 at 4:13

noobie-phpnoobie-php

6,14715 gold badges49 silver badges94 bronze badges

6

In PHP you can use intval(string) or floatval(string) functions to convert strings to numbers.

answered Dec 16, 2011 at 4:11

Kashif KhanKashif Khan

2,56514 silver badges14 bronze badges

2

You can always add zero to it!

Input             Output
'2' + 0           2 (int)
'2.34' + 0        2.34 (float)
'0.3454545' + 0   0.3454545 (float)

answered Jul 18, 2016 at 8:13

BoykodevBoykodev

8201 gold badge10 silver badges21 bronze badges

2

Just a little note to the answers that can be useful and safer in some cases. You may want to check if the string actually contains a valid numeric value first and only then convert it to a numeric type (for example if you have to manipulate data coming from a db that converts ints to strings). You can use is_numeric() and then floatval():

$a = "whatever"; // any variable

if (is_numeric($a)) 
    var_dump(floatval($a)); // type is float
else 
    var_dump($a); // any type

answered Aug 10, 2013 at 17:16

taseenbtaseenb

1,3481 gold badge15 silver badges30 bronze badges

1

Here is the function that achieves what you are looking for. First we check if the value can be understood as a number, if so we turn it into an int and a float. If the int and float are the same (e.g., 5 == 5.0) then we return the int value. If the int and float are not the same (e.g., 5 != 5.3) then we assume you need the precision of the float and return that value. If the value isn't numeric we throw a warning and return null.

function toNumber($val) {
    if (is_numeric($val)) {
        $int = (int)$val;
        $float = (float)$val;

        $val = ($int == $float) ? $int : $float;
        return $val;
    } else {
        trigger_error("Cannot cast $val to a number", E_USER_WARNING);
        return null;
    }
}

answered Jan 1, 2016 at 19:51

If you want the numerical value of a string and you don't want to convert it to float/int because you're not sure, this trick will convert it to the proper type:

function get_numeric($val) {
  if (is_numeric($val)) {
    return $val + 0;
  }
  return 0;
}

Example:

Source: https://www.php.net/manual/en/function.is-numeric.php#107326

answered Sep 29, 2020 at 8:11

klodomaklodoma

3,8831 gold badge27 silver badges39 bronze badges

1

In addition to Boykodev's answer I suggest this:

Input             Output
'2' * 1           2 (int)
'2.34' * 1        2.34 (float)
'0.3454545' * 1   0.3454545 (float)

answered Oct 3, 2016 at 13:29

drugandrugan

7208 silver badges10 bronze badges

5

I've been reading through answers and didn't see anybody mention the biggest caveat in PHP's number conversion.

The most upvoted answer suggests doing the following:

$str = "3.14"
$intstr = (int)$str // now it's a number equal to 3

That's brilliant. PHP does direct casting. But what if we did the following?

$str = "3.14is_trash"
$intstr = (int)$str

Does PHP consider such conversions valid?

Apparently yes.

PHP reads the string until it finds first non-numerical character for the required type. Meaning that for integers, numerical characters are [0-9]. As a result, it reads 3, since it's in [0-9] character range, it continues reading. Reads . and stops there since it's not in [0-9] range.

Same would happen if you were to cast to float or double. PHP would read 3, then ., then 1, then 4, and would stop at i since it's not valid float numeric character.

As a result, "million" >= 1000000 evaluates to false, but "1000000million" >= 1000000 evaluates to true.

See also:

https://www.php.net/manual/en/language.operators.comparison.php how conversions are done while comparing

https://www.php.net/manual/en/language.types.string.php#language.types.string.conversion how strings are converted to respective numbers

answered Jun 15, 2019 at 17:52

DragasDragas

9189 silver badges23 bronze badges

2

Only multiply the number by 1 so that the string is converted to type number.

//String value
$string = "5.1"
if(is_numeric($string)){
  $numeric_string = $string*1;
}

answered Nov 2, 2019 at 15:44

rolodefrolodef

1071 silver badge3 bronze badges

3

Here is a function I wrote to simplify things for myself:

It also returns shorthand versions of boolean, integer, double and real.

function type($mixed, $parseNumeric = false)
{        
    if ($parseNumeric && is_numeric($mixed)) {
        //Set type to relevant numeric format
        $mixed += 0;
    }
    $t = gettype($mixed);
    switch($t) {
        case 'boolean': return 'bool'; //shorthand
        case 'integer': return 'int';  //shorthand
        case 'double': case 'real': return 'float'; //equivalent for all intents and purposes
        default: return $t;
    }
}

Calling type with parseNumeric set to true will convert numeric strings before checking type.

Thus:

type("5", true) will return int

type("3.7", true) will return float

type("500") will return string

Just be careful since this is a kind of false checking method and your actual variable will still be a string. You will need to convert the actual variable to the correct type if needed. I just needed it to check if the database should load an item id or alias, thus not having any unexpected effects since it will be parsed as string at run time anyway.

Edit

If you would like to detect if objects are functions add this case to the switch:

case 'object': return is_callable($mixed)?'function':'object';

answered Jan 23, 2014 at 20:30

Dieter GribnitzDieter Gribnitz

4,7222 gold badges40 silver badges36 bronze badges

I've found that in JavaScript a simple way to convert a string to a number is to multiply it by 1. It resolves the concatenation problem, because the "+" symbol has multiple uses in JavaScript, while the "*" symbol is purely for mathematical multiplication.

Based on what I've seen here regarding PHP automatically being willing to interpret a digit-containing string as a number (and the comments about adding, since in PHP the "+" is purely for mathematical addition), this multiply trick works just fine for PHP, also.

I have tested it, and it does work... Although depending on how you acquired the string, you might want to apply the trim() function to it, before multiplying by 1.

answered Feb 25, 2014 at 14:58

1

Late to the party, but here is another approach:

function cast_to_number($input) {
    if(is_float($input) || is_int($input)) {
        return $input;
    }
    if(!is_string($input)) {
        return false;
    }
    if(preg_match('/^-?\d+$/', $input)) {
        return intval($input);
    }
    if(preg_match('/^-?\d+\.\d+$/', $input)) {
        return floatval($input);
    }
    return false;
}

cast_to_number('123.45');       // (float) 123.45
cast_to_number('-123.45');      // (float) -123.45
cast_to_number('123');          // (int) 123
cast_to_number('-123');         // (int) -123
cast_to_number('foo 123 bar');  // false

answered Sep 10, 2020 at 10:46

BenniBenni

1,02311 silver badges14 bronze badges

1

Alright so I just ran into this issue. My problem is that the numbers/strings in question having varying numbers of digits. Some have no decimals, others have several. So for me, using int, float, double, intval, or floatval all gave me different results depending on the number.

So, simple solution... divide the string by 1 server-side. This forces it to a number and retains all digits while trimming unnecessary 0's. It's not pretty, but it works.

"your number string" / 1

Input       Output
"17"        17
"84.874"    84.874
".00234"    .00234
".123000"   .123
"032"       32

answered Oct 21, 2021 at 0:13

MikelGMikelG

4093 silver badges16 bronze badges

4

$a = "10";

$b = (int)$a;

You can use this to convert a string to an int in PHP.

answered Dec 16, 2011 at 4:13

PritomPritom

1,2548 gold badges19 silver badges37 bronze badges

2

You can use:

((int) $var)   ( but in big number it return 2147483647 :-) )

But the best solution is to use:

if (is_numeric($var))
    $var = (isset($var)) ? $var : 0;
else
    $var = 0;

Or

if (is_numeric($var))
    $var = (trim($var) == '') ? 0 : $var;
else
    $var = 0;

answered Sep 29, 2013 at 19:18

Simply you can write like this:

answered Aug 28, 2018 at 11:20

3

There is a way:

$value = json_decode(json_encode($value, JSON_NUMERIC_CHECK|JSON_PRESERVE_ZERO_FRACTION|JSON_UNESCAPED_SLASHES), true);

Using is_* won't work, since the variable is a: string.

Using the combination of json_encode() and then json_decode() it's converted to it's "true" form. If it's a true string then it would output wrong.

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

var_dump($num, $int, $float);

Will output: string(2) "Me" int(0) float(0)

answered May 28, 2019 at 19:04

AnugaAnuga

2,30516 silver badges25 bronze badges

1

You can change the data type as follows

$number = "1.234";

echo gettype ($number) . "\n"; //Returns string

settype($number , "float");

echo gettype ($number) . "\n"; //Returns float

For historical reasons "double" is returned in case of a float.

PHP Documentation

aksu

5,1815 gold badges23 silver badges39 bronze badges

answered Sep 4, 2013 at 10:53

Now we are in an era where strict/strong typing has a greater sense of importance in PHP, I use json_decode:

$num = json_decode('123');

var_dump($num); // outputs int(123)

$num = json_decode('123.45');

var_dump($num); // outputs float(123.45)

answered Aug 21, 2021 at 19:49

AndyAndy

4,7365 gold badges33 silver badges56 bronze badges

2

function convert_to_number($number) {
    return is_numeric($number) ? ($number + 0) : FALSE;
}

answered Apr 11 at 10:53

HefHef

3383 silver badges11 bronze badges

All suggestions lose the numeric type.

This seems to me a best practice:

function str2num($s){
// Returns a num or FALSE
    $return_value =  !is_numeric($s) ? false :               (intval($s)==floatval($s)) ? intval($s) :floatval($s);
    print "\nret=$return_value type=".gettype($return_value)."\n";
}

answered Apr 29, 2015 at 20:34

If you don't know in advance if you have a float or an integer,
and if the string may contain special characters (like space, €, etc),
and if it may contain more than 1 dot or comma,
you may use this function:

// This function strip spaces and other characters from a string and return a number.
// It works for integer and float.
// It expect decimal delimiter to be either a '.' or ','
// Note: everything after an eventual 2nd decimal delimiter will be removed.
function stringToNumber($string) {
    // return 0 if the string contains no number at all or is not a string:
    if (!is_string($string) || !preg_match('/\d/', $string)) {
        return 0;
    } 

    // Replace all ',' with '.':
    $workingString = str_replace(',', '.', $string);

    // Keep only number and '.':
    $workingString = preg_replace("/[^0-9.]+/", "", $workingString);

    // Split the integer part and the decimal part,
    // (and eventually a third part if there are more 
    //     than 1 decimal delimiter in the string):
    $explodedString = explode('.', $workingString, 3);

    if ($explodedString[0] === '') {
        // No number was present before the first decimal delimiter, 
        // so we assume it was meant to be a 0:
        $explodedString[0] = '0';
    } 

    if (sizeof($explodedString) === 1) {
        // No decimal delimiter was present in the string,
        // create a string representing an integer:
        $workingString = $explodedString[0];
    } else {
        // A decimal delimiter was present,
        // create a string representing a float:
        $workingString = $explodedString[0] . '.' .  $explodedString[1];
    }

    // Create a number from this now non-ambiguous string:
    $number = $workingString * 1;

    return $number;
}

answered Feb 12, 2020 at 17:44

4

//Get Only number from string
$string = "123 Hello Zahid";
$res = preg_replace("/[^0-9]/", "", $string);
echo $res."
";
//Result 123

answered Sep 9, 2020 at 18:54

How do I convert a string to a number?

Can you use numbers in variables PHP?

Can we use int in PHP?

How do you convert one variable type to another in PHP?