is_scalar

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

is_scalar — Finds whether a variable is a scalar

Опис

is_scalar(mixed $value): bool

Finds whether the given variable is a scalar.

Scalar variables are those containing an int, float, string or bool. Types array, object, resource and null are not scalar.

Зауваження:
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.

Зауваження:
is_scalar() does not consider NULL to be scalar.

Параметри

value: The variable being evaluated.

Значення, що повертаються

Returns true if value is a scalar, false otherwise.

Приклади

Приклад #1 is_scalar() example

<?php
function show_var($var) 
{
    if (is_scalar($var)) {
        echo $var;
    } else {
        var_dump($var);
    }
}
$pi = 3.1416;
$proteins = array("hemoglobin", "cytochrome c oxidase", "ferredoxin");

show_var($pi);
show_var($proteins)

?>

Поданий вище приклад виведе:

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

Прогляньте також

is_float() - Finds whether the type of a variable is float
is_int() - Find whether the type of a variable is integer
is_numeric() - Finds whether a variable is a number or a numeric string
is_real() - Псевдонім is_float
is_string() - Перевіряє, чи має задана змінна рядковий тип даних
is_bool() - Finds out whether a variable is a boolean
is_object() - Finds whether a variable is an object
is_array() - Finds whether a variable is an array

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User Contributed Notes 3 notes

down

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.

down

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:
<?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 scalars

down

efelch at gmail dot com ¶

19 years ago

A 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.

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