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(PHP 4, PHP 5, PHP 7, PHP 8)
in_array — Checks if a value exists in an array
Searches for needle in haystack using loose comparison
unless strict is set.
needleThe searched value.
Note:
If
needleis a string, the comparison is done in a case-sensitive manner.
haystackThe array.
strict
If the third parameter strict is set to true
then the in_array() function will also check the
types of the
needle in the haystack.
Note:
Prior to PHP 8.0.0, a non-numeric string
needlewould loosely match ahaystackvalue of0, and vice versa. As of PHP 8.0.0, the number is converted to a string and the two are compared as strings, so only a numeric string of the same value still matches.Non-strict mode nonetheless uses loose comparison, so values of different types can still compare as equal:
truematches any truthy string, andfalsematches both""and"0". Unless the types of all values involved are known with certainty, always passstrictto force an identity comparison.
Example #1 in_array() example
<?php
$os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os)) {
echo "Got Irix";
}
if (in_array("mac", $os)) {
echo "Got mac";
}
?>The second condition fails because in_array() is case-sensitive, so the program above will display:
Got Irix
Example #2 in_array() with strict example
<?php
$a = array('1.10', 12.4, 1.13);
if (in_array('12.4', $a, true)) {
echo "'12.4' found with strict check\n";
}
if (in_array(1.13, $a, true)) {
echo "1.13 found with strict check\n";
}
?>The above example will output:
1.13 found with strict check
Example #3 in_array() with an array as needle
<?php
$a = array(array('p', 'h'), array('p', 'r'), 'o');
if (in_array(array('p', 'h'), $a)) {
echo "'ph' was found\n";
}
if (in_array(array('f', 'i'), $a)) {
echo "'fi' was found\n";
}
if (in_array('o', $a)) {
echo "'o' was found\n";
}
?>The above example will output:
'ph' was found 'o' was found
