What’s the Difference Between is_int and is_numeric Functions? When Should You Use is_int Instead of is_numeric?

gitbox 2025-08-25

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What’s the Difference Between is_int and is_numeric Functions? When Should You Use is_int Instead of is_numeric?

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In PHP, is_int and is_numeric are two functions used to check variable types or contents, but their purposes and evaluation logic differ significantly.

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1. is_int Function

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The is_int function is used to determine whether a variable is of integer type. It returns true only if the variable’s data type is integer. Even if the value looks like an integer, if the type isn’t integer, it will return false.

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<br>
$a = 123;<br>
var_dump(is_int($a)); // Output: bool(true)</p>
<p>$b = '123';<br>
var_dump(is_int($b)); // Output: bool(false)<br>

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2. is_numeric Function

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The is_numeric function checks whether a variable’s value is a number or a numeric string. It can identify integers, floats, and numeric strings.

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<br>
$a = 123;<br>
var_dump(is_numeric($a)); // Output: bool(true)</p>
<p>$b = '123';<br>
var_dump(is_numeric($b)); // Output: bool(true)</p>
<p>$c = '12.3';<br>
var_dump(is_numeric($c)); // Output: bool(true)</p>
<p>$d = 'abc';<br>
var_dump(is_numeric($d)); // Output: bool(false)<br>

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3. Comparison of Use Cases

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Use is_int when you need the variable to be strictly an integer type (numeric strings or floats are not accepted). For example, array indexes, loop counters, or integer fields in a database.
Use is_numeric when you only care whether the value is a number or can be converted to a number, regardless of its type. For example, user input, form data, or configuration values.

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4. Summary

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In short, is_int performs strict type checking, while is_numeric performs loose value checking. Which function to use depends on how strictly you need to enforce type and data source rules.

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is_int