How to get string length using strlen function in PHP

strlen() function is a built-in function in PHP, used to obtain the character length of a string. In many PHP projects, the length of the string is very important data, and the strlen() function becomes very useful at this time.

Next, let us introduce how to use the strlen function in PHP to get the string length.

1. Basic syntax

The basic syntax of the strlen() function is very simple. You only need to pass the string whose length you want to obtain as a parameter to the function. The specific format is as follows:

$str = "hello world";
echo strlen($str);//Output 11
?>

2. String encoding

strlen() function can handle ASCII-encoded and UTF-8-encoded strings. For ASCII encoding, the strlen() function returns the number of characters in the string. For an ASCII-encoded string containing N characters, the strlen() function will return N.

But in a UTF-8 encoded string, one character may be represented by multiple bytes. In this case, the strlen() function will return the number of bytes, not the number of characters. Therefore, when dealing with UTF-8 encoded strings, it is better to use the mb_strlen() function to get the number of characters in the string.

3. String truncation

Normally, we can use the strlen() function to get the length of the string to conveniently process the string content. But sometimes we also need to truncate the string, in which case we need to use the substr() function. The substr() function can intercept the string content of the specified length starting from the specified position.

The following is an example:

$str = "hello world";
echo substr($str,0,5);//Output hello
?>

In the above example, the substr() function intercepts a string of length 5 starting from the 0th position of the string $str and outputs it.

4. Conclusion

In PHP, the strlen() function is often used to obtain the length of a string and is a very practical function. Pay attention to encoding issues when writing code to avoid inaccurate length data. At the same time, since this function can only obtain the length of the string, other functions are still needed to implement string truncation and other operations.

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