(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)
is_scalar — Indique si une variable est un scalaire
Indique si une expression est évaluée en tant que valeur scalaire.
Voir types scalaires pour plus d'informations.
Note:
is_scalar() ne considère pas les valeurs des types resource comme scalaires, étant donné que les ressources sont des types abstraits, basés sur des entiers. Ceci est susceptible de changer.
Note:
La fonction is_scalar() ne considère pas la valeur NULL comme un scalaire.
valueLa variable à évaluer.
Exemple #1 Exemple avec is_scalar()
<?php
function show_var($var)
{
if (is_scalar($var)) {
echo $var;
} else {
var_dump($var);
}
}
$pi = 3.1416;
$proteines = array("hémoglobine", "cytochrome c oxidase", "ferredoxine");
show_var($pi);
show_var($proteines)
?>L'exemple ci-dessus va afficher :
3.1416
array(3) {
[0]=>
string(11) "hémoglobine"
[1]=>
string(20) "cytochrome c oxidase"
[2]=>
string(11) "ferredoxine"
}
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.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:
<?php
echo('is_scalar() test:'.EOL);
echo("NULL: " . print_R(is_scalar(NULL), true) . EOL);
echo("false: " . print_R(is_scalar(false), true) . EOL);
echo("(empty): " . print_R(is_scalar(''), true) . EOL);
echo("0: " . print_R(is_scalar(0), true) . EOL);
echo("'0': " . print_R(is_scalar('0'), true) . EOL);
?>
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 scalarsA scalar is a single item or value, compared to things like arrays and objects which have multiple values. This tends to be the standard definition of the word in terms of programming. An integer, character, etc are scalars. Strings are probably considered scalars since they only hold "one" value (the value represented by the characters represented) and nothing else.