(PHP 4, PHP 5, PHP 7, PHP 8)
is_float — Finds whether the type of a variable is float
Finds whether the type of the given variable is float.
Note:
To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric().
valueThe variable being evaluated.
Example #1 is_float() example
<?php
var_dump(is_float(27.25));
var_dump(is_float('abc'));
var_dump(is_float(23));
var_dump(is_float(23.5));
var_dump(is_float(1e7)); //Scientific Notation
var_dump(is_float(true));
?>The above example will output:
bool(true) bool(false) bool(false) bool(true) bool(true) bool(false)
Coercing the value to float and back to string was a neat trick. You can also just add a literal 0 to whatever you're checking.
<?php
function isfloat($value) {
// PHP automagically tries to coerce $value to a number
return is_float($value + 0);
}
?>
Seems to work ok:
<?php
isfloat("5.0" + 0); // true
isfloat("5.0"); // false
isfloat(5 + 0); // false
isfloat(5.0 + 0); // false
isfloat('a' + 0); // false
?>
YMMVIf you want to test whether a string is containing a float, rather than if a variable is a float, you can use this simple little function:
function isfloat($f) return ($f == (string)(float)$f);is_float() returns true for NAN, INF and -INF. You may want to test is_float($value) && is_finite($value), or alternatively filter_var($value, FILTER_VALIDATE_FLOAT) !== false.As celelibi at gmail dot com stated, is_float checks ONLY the type of the variable not the data it holds!
If you want to check if string represent a floating point value use the following regular expression and not is_float(),
or poorly written custom functions.
/^[+-]?(([0-9]+)|([0-9]*\.[0-9]+|[0-9]+\.[0-9]*)|
(([0-9]+|([0-9]*\.[0-9]+|[0-9]+\.[0-9]*))[eE][+-]?[0-9]+))$/