PHP: Hypertext Preprocessor (original) (raw)

is_scalar

(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)

is_scalar — Finds whether a variable is a scalar

Description

See scalar types for more information.

Note:

is_scalar() does not consider resource type values to be scalar as resources are abstract datatypes which are currently based on integers. This implementation detail should not be relied upon, as it may change.

Note:

is_scalar() does not consider NULL to be scalar.

Parameters

value

The variable being evaluated.

Return Values

Returns [true](reserved.constants.php#constant.true) if value is a scalar, [false](reserved.constants.php#constant.false) otherwise.

Examples

Example #1 is_scalar() example

<?php function show_var($var) { if (is_scalar($var)) { echo $var, PHP_EOL; } else { var_dump($var); } }$pi = 3.1416; <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>p</mi><mi>r</mi><mi>o</mi><mi>t</mi><mi>e</mi><mi>i</mi><mi>n</mi><mi>s</mi><mo>=</mo><mi>a</mi><mi>r</mi><mi>r</mi><mi>a</mi><mi>y</mi><mo stretchy="false">(</mo><mi mathvariant="normal">"</mi><mi>h</mi><mi>e</mi><mi>m</mi><mi>o</mi><mi>g</mi><mi>l</mi><mi>o</mi><mi>b</mi><mi>i</mi><mi>n</mi><mi mathvariant="normal">"</mi><mo separator="true">,</mo><mi mathvariant="normal">"</mi><mi>c</mi><mi>y</mi><mi>t</mi><mi>o</mi><mi>c</mi><mi>h</mi><mi>r</mi><mi>o</mi><mi>m</mi><mi>e</mi><mi>c</mi><mi>o</mi><mi>x</mi><mi>i</mi><mi>d</mi><mi>a</mi><mi>s</mi><mi>e</mi><mi mathvariant="normal">"</mi><mo separator="true">,</mo><mi mathvariant="normal">"</mi><mi>f</mi><mi>e</mi><mi>r</mi><mi>r</mi><mi>e</mi><mi>d</mi><mi>o</mi><mi>x</mi><mi>i</mi><mi>n</mi><mi mathvariant="normal">"</mi><mo stretchy="false">)</mo><mo separator="true">;</mo><mi>s</mi><mi>h</mi><mi>o</mi><msub><mi>w</mi><mi>v</mi></msub><mi>a</mi><mi>r</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">proteins = array("hemoglobin", "cytochrome c oxidase", "ferredoxin");show_var(</annotation></semantics></math>proteins=array("hemoglobin","cytochromecoxidase","ferredoxin");showvar(pi); show_var($proteins)?>

The above example will output:

3.1416 array(3) { [0]=> string(10) "hemoglobin" [1]=> string(20) "cytochrome c oxidase" [2]=> string(10) "ferredoxin" }

Found A Problem?

Dr K ¶

19 years ago

`Having hunted around the manual, I've not found a clear statement of what makes a type "scalar" (e.g. if some future version of the language introduces a new kind of type, what criterion will decide if it's "scalar"? - that goes beyond just listing what's scalar in the current version.)

In other lanuages, it means "has ordering operators" - i.e. "less than" and friends.

It (-:currently:-) appears to have the same meaning in PHP.

Anonymous ¶

18 years ago

`Another warning in response to the previous note:

just a warning as it appears that an empty value is not a scalar.

That statement is wrong--or, at least, has been fixed with a later revision than the one tested. The following code generated the following output on PHP 4.3.9.

CODE:

OUTPUT:
is_scalar() test:
NULL:
false: 1
(empty): 1
0: 1
'0': 1

THUS:

NULL is NOT a scalar
false, (empty string), 0, and "0" ARE scalars

efelch at gmail dot com ¶