Using PHP is_int() Function to Check Integer Variables

PHP is a widely used scripting language in web development, providing many useful functions for handling data. One of them is the is_int function, which can be used to check whether a variable is an integer.

The is_int function syntax is as follows:

bool is_int (mixed $var)

In this signature, $var is the variable to be checked. The function returns a boolean value: true if the variable is of integer type, otherwise false .

Below is an example code using the is_int function:

<?php
$var1 = 10;
$var2 = "5";
$var3 = 3.14;

if (is_int($var1)) {
    echo '$var1 是一个整型';
} else {
    echo '$var1 不是一个整型';
}

echo "
";

if (is_int($var2)) {
    echo '$var2 是一个整型';
} else {
    echo '$var2 不是一个整型';
}

echo "
";

if (is_int($var3)) {
    echo '$var3 是一个整型';
} else {
    echo '$var3 不是一个整型';
}
?>

The above code produces the following output:

$var1 是一个整型
$var2 不是一个整型
$var3 不是一个整型

From the output we can see that the is_int function correctly determines whether a variable is an integer. In this example, $var1 is an integer, $var2 is a string, and $var3 is a floating‑point number.

Note that is_int only checks the variable's type, not whether its value represents an integer. To validate the value, you can use other functions such as intval .