PHP mb_stripos() Function: Usage and Examples

When working with PHP, you may need to find the first case-insensitive character position. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.

mb_stripos: Returns a zero-based character position or false if no match occurs.

What Is mb_stripos in PHP?

Find the first case-insensitive character position. Returns a zero-based character position or false if no match occurs.

Syntax:

mb_stripos(string $haystack, string $needle, int $offset = 0, ?string $encoding = null): int|false

Parameters and return value: The signature above identifies the arguments and return type where the API has a single call. For topic guides, follow the sequence of calls in the examples. Always distinguish a returned value from an object or variable modified by reference.

Important: A match at index zero is valid and must not be confused with false. Case-insensitive matching is not the same as accent-insensitive comparison.

Example 1: Basic Usage

This example introduces the operation with a short and predictable input.

<?php

var_dump(mb_stripos("Hello World", "world", 0, "UTF-8"));

The code focuses on the main operation. Returns a zero-based character position or false if no match occurs.

Example 2: Another Case

Now compare a different input, locale, date, or option to see another part of the behavior.

<?php

var_dump(mb_stripos("Café menu", "MENU", 0, "UTF-8"));

What changes? A match at index zero is valid and must not be confused with false. Case-insensitive matching is not the same as accent-insensitive comparison.

Practical Example: Applying It in an Application

Use the following separate example as a starting point for a small application task. Check any extension or environment requirements below before running it.

<?php

$titles = ["Daily Report", "Weekly summary", "Monthly REPORT"];
foreach ($titles as $title) {
    if (mb_stripos($title, "report", 0, "UTF-8") !== false) {
        echo $title . PHP_EOL;
    }
}

The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. Returns a zero-based character position or false if no match occurs.

Important Behavior and Edge Cases

• Core behavior: Returns a zero-based character position or false if no match occurs.
• Inputs and results: A match at index zero is valid and must not be confused with false. Case-insensitive matching is not the same as accent-insensitive comparison.
• Alternatives: mb_strpos() performs case-sensitive searches; stripos() uses byte offsets.
• Compatibility: mbstring is required for mb_* functions.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• mb_stripos helps you find the first case-insensitive character position.
• Returns a zero-based character position or false if no match occurs.
• A match at index zero is valid and must not be confused with false. Case-insensitive matching is not the same as accent-insensitive comparison.

Use mb_stripos when you need to find the first case-insensitive character position. Start with the first example, compare the second, and adapt the practical example to your inputs. Confirm the return value and environment requirements before adding it to production code.