Can is_integer and in_array Determine Whether an Array Contains an Integer Value?

gitbox 2025-09-01

<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-comment">// This article is written in PHP to explore whether is_integer and in_array can be used to determine if an array contains an integer value.</span></span><span>
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<p><span class="hljs-comment">/**</p>
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<p>Title: Can is_integer and in_array Determine Whether an Array Contains an Integer Value?</p>
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<p>In daily development, we often need to check if an array contains a certain integer value. At this point, <code>in_array

is_integer(5); // true

is_integer("5"); // false

is_integer(5.0); // false

Therefore, is_integer itself is not used to determine whether a value exists in an array, but rather to check types.

2. The Role and Pitfalls of in_array

in_array(mixed $needle, array $haystack, bool $strict = false): bool checks whether a certain value exists in an array.

When the third parameter $strict is false (default), non-strict comparison is used, allowing type conversion.

When $strict is true, both type and value must match exactly.

Example:

$arr = [1, "2", 3];

in_array(2, $arr); // true (because "2" == 2)

in_array(2, $arr, true); // false (because 2 !== "2")

in_array(1, $arr, true); // true (because 1 === 1)

Thus, in_array can effectively check whether a value exists in an array, but whether it considers type depends on the $strict parameter.

3. Can They Be Used to Check Whether an Array Contains “Integer Values”?

If your requirement is to determine whether an array “contains an integer type value,” not just a value that “can be converted into an integer,” then note two points:

Use in_array($value, $array, true) to ensure the type is integer.

If you need to check whether an array “contains at least one integer type value,” you can combine is_integer with iteration.

Example: Checking if an array contains at least one integer type value

$arr = [1, "2", 3.0, true];

$hasInt = false;

foreach ($arr as $item) {

if (is_integer($item)) {

    $hasInt = true;

    break;

}

var_dump($hasInt); // true, because 1 is an integer type

4. Summary

is_integer is used to check whether a variable is of integer type, and cannot directly determine whether an array contains a specific value.

in_array can be used to check if an array contains a certain value, but if $strict is not set to true, automatic type conversion may occur, leading to inaccurate results.

To determine whether an array contains an integer type value, use is_integer combined with iteration.

Best Practice:

If you specifically want to check “whether the array contains a value equal to a certain integer and of type int,” you should use:

in_array(5, $array, true);

If you want to check “whether the array contains any integer type values,” you can use:

array_filter($array, 'is_int');

Or:

$hasInt = (bool) array_filter($array, 'is_int');

This ensures that both the value and type are checked accurately.
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is_integer