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In PHP programming, it is often necessary to determine whether a variable is an integer type to ensure the correctness of the data and the strictness of the logic. PHP provides a built-in function is_int() to accomplish this function. This article will introduce in detail the usage methods, precautions and examples of the is_int() function to help you better understand and apply this function.
is_int() is a built-in function in PHP, which is used to determine whether the passed variable is an integer type ( integer ). Return true if the variable is of an integer type, otherwise false .
Its function prototype is as follows:
bool is_int ( mixed $var )
The parameter $var is the variable you want to judge.
is_int() only checks whether the variable is an integer ( int ), regardless of whether the value is a numeric string or not.
is_numeric() is used to determine whether a variable is a numeric string, but does not distinguish between types.
ctype_digit() is used to determine whether a string contains only numeric characters.
Therefore, if you just want to confirm that the type of a variable is an integer, is_int() is the most straightforward way.
Here are some simple examples using is_int() :
<?php
$var1 = 123;
$var2 = "123";
$var3 = 12.3;
var_dump(is_int($var1)); // Output: bool(true)
var_dump(is_int($var2)); // Output: bool(false)，Because it's a string
var_dump(is_int($var3)); // Output: bool(false)，Because it's a floating point number
?>
Sometimes a variable may be a string, but you want to tell if it represents an integer. is_int() cannot determine whether the string number is an integer. At this time, it can be implemented in combination with other functions:
<?php
$var = "456";
if (is_int($var)) {
echo "Variable is an integer type";
} elseif (is_numeric($var) && (int)$var == $var) {
echo "Variables are numeric strings，And represent integers";
} else {
echo "Variables are not integers";
}
?>
is_int() only determines whether the type of the variable is int .
For numeric strings, is_int() returns false .
Combining is_numeric() and type conversion, you can determine whether the numeric string is an integer value.
This function is simple to use and efficient, and is a recommended way to judge integer types.
If you want to know more about PHP function usage, you can visit gitbox.net/php-doc .
