Check string is float php

What is the easiest way to check if a string contains a valid float?

For example

is_string_float("1") = true
is_string_float("1.234") = true
is_string_float("1.2e3") = true
is_string_float("1b2") = false
is_string_float("aldhjsfb") = false

asked Dec 5, 2016 at 11:51

3

The easiest way would be to use built in function is_float(). To test if a variable is a number or a numeric string you must use is_numeric().

answered Dec 5, 2016 at 12:02

1

If you really want to know if a string contains a float and ONLY a float you cannot use is_float() (wrong type) or is_numeric() (returns true for a string like "1" too) only. I'd use

instead.

answered Jul 2, 2019 at 11:50

Lenny EingLenny Eing

1311 silver badge8 bronze badges

maybe you can use a couple of functions

out of the box

function is_string_float($string) {
    if(is_numeric($string)) {
        $val = $string+0;

        return is_float($val);
    } 
      
    return false;
}

answered Dec 5, 2016 at 11:57

donald123donald123

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2

This can easily be achieved by double casting.

/**
 * @param string $text
 * @return bool
 */
function is_string_float(string $text): bool
{
    return $text === (string) (float) $text;
}

answered Oct 5, 2021 at 9:35

1

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I am trying to check in php if a string is a double or not.

Here is my code:

   if(floatval($num)){
         $this->print_half_star();
    }

$num is a string..The problem is that even when there is an int it gives true. Is there a way to check if it is a float and not an int!?

asked Aug 7, 2012 at 15:54

1

// Try to convert the string to a float
$floatVal = floatval($num);
// If the parsing succeeded and the value is not equivalent to an int
if($floatVal && intval($floatVal) != $floatVal)
{
    // $num is a float
}

answered Aug 7, 2012 at 16:02

4

This will omit integer values represented as strings:

if(is_numeric($num) && strpos($num, ".") !== false)
{
    $this->print_half_star();
}

answered Aug 7, 2012 at 16:01

JK.JK.

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1

You can try this:

function isfloat($num) {
    return is_float($num) || is_numeric($num) && ((float) $num != (int) $num);
}

var_dump(isfloat(10));     // bool(false)
var_dump(isfloat(10.5));   // bool(true)
var_dump(isfloat("10"));   // bool(false)
var_dump(isfloat("10.5")); // bool(true)

answered Aug 7, 2012 at 16:02

FlorentFlorent

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1

You could just check if the value is numeric, and then check for a decimal point, so...

if(is_numeric($val) && stripos($val,'.') !== false)
{
    //definitely a float
}

It doesn't handle scientific notation very well though, so you may have to handle that manually by looking for e

answered Nov 28, 2018 at 19:27

Why not use the magic of regular expression

answered Aug 7, 2012 at 16:03

ARIF MAHMUD RANAARIF MAHMUD RANA

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2

if "double string format " like this "XXXXXX.XXXXXX"

try check

function check_double_string($str){
 $pairs = explode('.',$str);
 if ( is_array($pairs) && count($pairs)==2) {
   return ( is_numeric($pairs[0]) && is_numeric($pairs[1])? true : false; 
 }
 return false;
}

answered Aug 7, 2012 at 16:05

voodoo417voodoo417

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1

In order to get all cases of a float we've got to add any zero's back on to the end that may be chopped off by floatval() or by typecasting (float)$num

$num='17.000010';
$num_float = (float)$num; //$num_float is now 17.00001  
//add the zero's back to $num_float
while (strlen ($num) > strlen ($num_float))  $num_float = $num_float . '0';   //$spot_float in now a string again


if($num_float != $num) then $num was no double :;

note !== was not used just in case $num_float was never converted back to a string by adding zeroes. such would be the case for values that didn't end in 0.

answered Apr 20, 2016 at 21:34

Here's what I ended up creating, for modern PHP:

/**
 * Determines if a variable appears to be a float or not.
 *
 * @param string|int|double $number
 * @return bool True if it appears to be an integer value. "75.0000" returns false.
 * @throws InvalidArgumentException if $number is not a valid number.
 */
function isFloatLike($number): bool
{
    // Bail if it isn't even a number.
    if (!is_numeric($number)) {
        throw new InvalidArgumentException("'$number' is not a valid number.");
    }

    // Try to convert the variable to a float.
    $floatVal = floatval($number);

    // If the parsing succeeded and the value is not equivalent to an int, 
    return ($floatVal && intval($floatVal) != $floatVal);
}

answered Apr 10, 2019 at 4:34

Theodore R. SmithTheodore R. Smith

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Not the answer you're looking for? Browse other questions tagged php or ask your own question.

Is float in PHP example?

A float is a number with a decimal point or a number in exponential form. 2.0, 256.4, 10.358, 7.64E+5, 5.56E-5 are all floats. The float data type can commonly store a value up to 1.7976931348623E+308 (platform dependent), and have a maximum precision of 14 digits.

How check value is decimal or not in PHP?

The is_numeric() function in the PHP programming language is used to evaluate whether a value is a number or numeric string. Numeric strings contain any number of digits, optional signs such as + or -, an optional decimal, and an optional exponential. Therefore, +234.5e6 is a valid numeric string.

How does PHP calculate float value?

Dealing with floating-point calculations in PHP.

1 – work on Integers. echo intval((0.1*10) + (0.7*10)); // int(8) ... .

2 – the round() function. echo intval(round((0.1+0.7)*10, 0)); // int(8) ... .

3 – casting to string. echo intval(strval((0.1+0.7)*10)); // int(8) ... .

4 – BC Math. ... .

Summary..

Is float a value?

Integers and floats are two different kinds of numerical data. An integer (more commonly called an int) is a number without a decimal point. A float is a floating-point number, which means it is a number that has a decimal place. Floats are used when more precision is needed.