PHP is_string() Function
Quick summary: The PHP is_string() function checks whether a variable is of type string.
PHP is_string() Syntax
is_string(mixed $value): boolPHP
PHP is_string() Basic examples
var_dump(is_string("hello"));PHP
Output:
bool(true)Returns true for strings.
var_dump(is_string(123));PHP
Output:
bool(false)Integers are not strings.
PHP is_string() Real-world usage
$name = "John";
if (is_string($name)) {
echo 'Valid name';
}PHP
Output:
Valid nameEnsures input is a string.
PHP is_string() Edge cases
var_dump(is_string(null));PHP
Output:
bool(false)Null is not a string.
PHP is_string() Common mistakes
Confusing stringable values with strings
Objects with __toString are not strings.
Incorrect
is_string(new DateTime());Correct
(string) new DateTime();Cast explicitly if string output is required.
PHP is_string() Frequently Asked Questions
What does is_string() do?
Checks if a variable is a string.
Return type?
Boolean.
Does it modify variable?
No.
Is numeric string a string?
Yes.
Use case?
Type checking.
Handles empty string?
Yes.
Handles null?
No.
Handles objects?
No.
Difference from gettype()?
Returns boolean instead of string.
Performance?
Very fast.
Strict check?
Yes.
Alternative?
gettype().