Which of the following is the use of strlen () function in php?

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What is the use of strlen () function in PHP?
What is the use of strlen () and strpos () functions in PHP?
What is the use of strpos () function in PHP?
What is the meaning of strlen () function?

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In this article, we will see how to get the length of the string using strlen() function in PHP, along with understanding its implementation through the examples.

The strlen() is a built-in function in PHP which returns the length of a given string. It takes a string as a parameter and returns its length. It calculates the length of the string including all the whitespaces and special characters.

Syntax:

strlen($string);

Parameters: The strlen() function accepts only one parameter $string which is mandatory. This parameter represents the string whose length is needed to be returned.

Return Value: The function returns the length of the $string including all the whitespaces and special characters.

Below programs illustrate the strlen() function in PHP:

Example 1: The below example demonstrates the use of the strlen() function in PHP.

PHP

$str = "GeeksforGeeks";

echo strlen($str);

?>

Output:

Example 2: This example demonstrates the use of the strlen() function where the string has special characters and escape sequences.

`PHP`

$str = "\n GeeksforGeeks Learning;";

echo strlen($str);

?>

Output:


Reference: http://php.net/manual/en/function.strlen.php
PHP is a server-side scripting language designed specifically for web development. You can learn PHP from the ground up by following this PHP Tutorial and PHP
Examples.

 
The strlen() function is used to get the string length. It returns the length of the string on success. If the string is empty, 0 is returned.
Syntax
strlen(str)
Parameters
str − The string for which we want the length.



Return
The strlen() function returns the length of the string on success. If the string is empty, 0 is returned.
Example
The following is an example −
 Live Demo
Output
The following is the output −
10
 
 Updated on 26-Dec-2019 09:24:59
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(PHP 4, PHP 5, PHP 7, PHP 8)
strlen — Get string length
Description
strlen(string $string): int
Parameters
 string The string being measured for length. 
Return Values
 The length of the string on success, and 0 if the string is empty. 
Examples
Example #1 A strlen() example

$str = 'abcdef';
echo strlen($str); // 6$str = ' ab cd ';
echo strlen($str); // 7
?>

Notes
Note: 

strlen() returns the number of bytes rather than the number of characters in a string. 
Note: 
 strlen() returns null when executed on arrays, and an E_WARNING level error is emitted. 
See Also
count() - Counts all elements in an array or in a Countable object
grapheme_strlen() - Get string length in grapheme units
iconv_strlen() - Returns
the character count of string
mb_strlen() - Get string length
 rm dot nasir at hotmail dot com ¶
6
years ago

I want to share something seriously important for newbies or beginners of PHP who plays with strings of UTF8 encoded characters or the languages like: Arabic, Persian, Pashto, Dari, Chinese (simplified), Chinese (traditional), Japanese, Vietnamese, Urdu, Macedonian, Lithuanian, and etc.
As the manual says: "strlen() returns the number of bytes rather than the number of characters in a string.", so if you want to get the number of characters in a string of UTF8 so use mb_strlen() instead of strlen().
Example:
// the Arabic (Hello) string below is: 59 bytes and 32 characters
$utf8 = "السلام علیکم ورحمة الله وبرکاته!";var_export( strlen($utf8) ); // 59
echo "
";
var_export( mb_strlen($utf8, 'utf8') ); // 32
?>

 chernyshevsky at hotmail dot com ¶



18 years ago

The easiest way to determine the character count of a UTF8 string is to pass the text through utf8_decode() first:

$length = strlen(utf8_decode($s));

?>



utf8_decode() converts characters that are not in ISO-8859-1 to '?', which, for the purpose of counting, is quite alright.

 joeri at sebrechts dot net ¶
6 years ago

When checking for length to make sure a value will fit in a database field, be mindful of using the right function.
There are three possible situations:
1. Most likely case: the database column is UTF-8 with a length defined in unicode code points (e.g. mysql varchar(200) for a utf-8 database).
// ok if php.ini default_charset set to UTF-8 (= default value)
mb_strlen($value);
iconv_strlen($value);
// always ok 
mb_strlen($value, "UTF-8");
iconv_strlen($value, "UTF-8");// BAD, do not use:
strlen(utf8_decode($value)); // breaks for some multi-byte characters
grapheme_strlen($value); // counts graphemes, not code points 
?>

2. The database column has a length defined in bytes (e.g. oracle's VARCHAR2(200 BYTE))
// ok, but assumes mbstring.func_overload is 0 in php.ini (= default value)
strlen($value);
// ok, forces count in bytes
mb_strlen($value, "8bit")
?>

3. The database column is in another character set (UTF-16, ISO-8859-1, etc...) with a length defined in characters / code points.
Find the character set used, and pass it explicitly to the length function.
// ok, supported charsets: http://php.net/manual/en/mbstring.supported-encodings.php
mb_strlen($value, $charset);
// ok, supported charsets: https://www.gnu.org/software/libiconv/
iconv_strlen($value, $charset);
?>

 jasonrohrer at fastmail dot
fm ¶
9 years ago

PHP's strlen function behaves differently than the C strlen function in terms of its handling of null bytes ('\0').  
In PHP, a null byte in a string does NOT count as the end of the string, and any null bytes are included in the length of the string.
For example, in PHP:
strlen( "te\0st" ) = 5
In C, the same call would return 2.
Thus, PHP's strlen function can be used to find the number of bytes in a binary string (for example, binary data returned by base64_decode).

 vcardillo at gmail dot com ¶
10 years ago

I would like to demonstrate that you need more than just this function in order to truly test for an empty string. The reason being that (null); ?> will return 0. So how do you know if the value was null, or truly an empty string?
$foo = null;
$len = strlen(null);
$bar = '';
echo 
"Length: " . strlen($foo) . "
";
echo "Length: $len 
";
echo "Length: " . strlen(null) . "
";if (strlen($foo) === 0) echo 'Null length is Zero 
';
if ($len === 0) echo 'Null length is still Zero 
';if (strlen($foo) == 0 && !is_null($foo)) echo '!is_null(): $foo is truly an empty string 
';
else echo '!is_null(): $foo is probably null 
';if (strlen($foo) == 0 && isset($foo)) echo 'isset(): $foo is truly an empty string 
';
else echo 'isset(): $foo is probably null 
';if (



strlen($bar) == 0 && !is_null($bar)) echo '!is_null(): $bar is truly an empty string 
';
else echo '!is_null(): $foo is probably null 
';if (strlen($bar) == 0 && isset($bar)) echo 'isset(): $bar is truly an empty string 
';
else echo 'isset(): $foo is probably null 
';
?>

// Begin Output:
Length: 0
Length: 0 
Length: 0
Null length is Zero 
Null length is still Zero 
!is_null(): $foo is probably null 
isset(): $foo is probably null 
!is_null(): $bar is truly an empty string 
isset(): $bar is truly an empty string 
// End Output
So it would seem you need either is_null() or isset() in addition to strlen() if you care whether or not the original value was null.
 basil at gohar dot us ¶
12 years ago

We just ran into what we thought was a bug but turned out to be a documented difference in behavior between PHP 5.2 & 5.3.  Take the following code example:
$attributes 
= array('one', 'two', 'three');if (strlen($attributes) == 0 && !is_bool($attributes)) {
    echo "We are in the 'if'\n";  //  PHP 5.3
} else {
    echo "We are in the 'else'\n";  //  PHP 5.2
}?>

This is because in 5.2 strlen will automatically cast anything passed to it as a string, and casting an array to a string yields the string "Array".  In 5.3, this changed, as noted in the following point in the backward incompatible changes in 5.3 (http://www.php.net/manual/en/migration53.incompatible.php):
"The newer internal parameter parsing API has been applied across all the extensions bundled with PHP 5.3.x. This parameter parsing API causes functions to return NULL when passed incompatible parameters. There are some exceptions to this rule, such as the get_class() function, which will continue to return FALSE on error."
So, in PHP 5.3, strlen($attributes) returns NULL, while in PHP 5.2, strlen($attributes) returns the integer 5.  This likely affects other functions, so if you are getting different behaviors or new bugs suddenly, check if you have upgraded to 5.3 (which we did recently), and then check for some warnings in your logs like this:
strlen() expects parameter 1 to be string, array given in /var/www/sis/lib/functions/advanced_search_lib.php on line 1028
If so, then you are likely experiencing this changed behavior.

John ¶
5 years ago

There's a LOT of misinformation here, which I want to correct! Many people have warned against using strlen(), because it is "super slow". Well, that was probably true in old versions of PHP. But as of PHP7 that's definitely no longer true. It's now SUPER fast!
I created a 20,00,000 byte string (~20 megabytes), and iterated ONE HUNDRED MILLION TIMES in a loop. Every loop iteration did a new strlen() on that very, very long string.
The result: 100 million strlen() calls on a 20 megabyte string only took a total of 488 milliseconds. And the strlen() calls didn't get slower/faster even if I made the string smaller or bigger. The strlen() was pretty much a constant-time, super-fast operation
So either PHP7 stores the length of every string as a field that it can simply always look up without having to count characters. Or it caches the result of strlen() until the string contents actually change. Either way, you should now never, EVER worry about strlen() performance again. As of PHP7, it is super fast!
Here is the complete benchmark code if you want to reproduce it on your machine:
$iterations 
= 100000000; // 100 million
$str = str_repeat( '0', 20000000 );// benchmark loop and variable assignment to calculate loop overhead
$start = microtime(true);
for( $i = 0; $i < $iterations; ++$i ) {
    $len = 0;
}
$end = microtime(true);
$loop_elapsed = 1000 * ($end - $start);// benchmark strlen in a loop
$len = 0;
$start = microtime(true);
for( $i = 0; $i < $iterations; ++$i ) {
    $len = strlen( $str );
}
$end = microtime(true);
$strlen_elapsed = 1000 * ($end - $start);// subtract loop overhead from strlen() speed calculation
$strlen_elapsed -= $loop_elapsed;echo "\nstring length: {$len}\ntest took: {$strlen_elapsed} milliseconds\n";?>
 
What is the use of strlen () function in PHP?
The strlen() is a built-in function in PHP which returns the length of a given string. It takes a string as a parameter and returns its length. It calculates the length of the string including all the whitespaces and special characters.
What is the use of strlen () and strpos () functions in PHP?
PHP String Functions.
 
What is the use of strpos () function in PHP?
strpos in PHP is a built-in function. Its use is to find the first occurrence of a substring in a string or a string inside another string. The function returns an integer value which is the index of the first occurrence of the string.
What is the meaning of strlen () function?
The strlen() function calculates the length of a given string. The strlen() function takes a string as an argument and returns its length. The returned value is of type size_t (an unsigned integer type). It is defined in the  header file.

programming php strpos() in php Strlen PHP PHP length array

Which of the following is the use of strlen () function in php?

PHP

PHP

Syntax

Parameters

Return

Example

Output

Description

Parameters

Return Values

Examples

Notes

See Also

What is the use of strlen () function in PHP?

What is the use of strlen () and strpos () functions in PHP?

What is the use of strpos () function in PHP?

What is the meaning of strlen () function?

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