When working with PHP, is_int can help with a specific task: checks whether a value has PHP integer type.
This guide shows what is_int does, how to use it in code, and which details you should check before relying on the result.
What Is is_int in PHP?
Checks whether a value has PHP integer type.
Usage: The following examples show calls with suitable values. Consult the function parameters described in the examples, especially when optional arguments or extensions are involved.
Example 1: Basic Usage
The first example introduces is_int with a direct PHP expression.
<?php
var_dump(is_int(42));
Observe the value returned or printed by is_int and compare it with the input used in this example.
Example 2: A Different Input or Option
This second example demonstrates another input or condition, so you can compare the behavior with the first example.
<?php
var_dump(is_int("42"));
Observe the value returned or printed by is_int and compare it with the input used in this example.
Practical Example
Here is a small scenario illustrating how is_int can fit into application code. Run the example only in an appropriate development environment if it reads files, changes data, starts processes or connects to a service.
<?php
$page = filter_var("12", FILTER_VALIDATE_INT); echo is_int($page) ? "Valid page" : "Invalid page";
Observe the value returned or printed by is_int and compare it with the input used in this example.
Important Behavior and Edge Cases
- Core behavior: Checks whether a value has PHP integer type.
- Important limitation: Numeric strings are not integers; filter external values rather than relying on casts.
- Production use: Check return values and handle failures before acting on the result.
Comparison With Related Functions
| Function or Approach | Difference |
|---|---|
is_int() | Checks whether a value has PHP integer type. |
filter_var() | Related approach. Its purpose and return value differ; select it when your task matches that operation. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Overlooking a special case of is_int(). | Numeric strings are not integers; filter external values rather than relying on casts. |
Using is_int() without checking the outcome. | Handle failures and confirm that the output is suitable for the next step. |
Key Takeaways
- Checks whether a value has PHP integer type.
- Numeric strings are not integers; filter external values rather than relying on casts.
- Test the function with relevant inputs before using it in production.
Use is_int when its behavior matches the job you need to complete. For dependable results, consider the input data, returned value and limitations shown above.