10 little-known but very useful functions in PHP

PHP has a very rich set of built-in functions, many of which we have used, but there are still many functions that most of us are not familiar with, but they are very useful. In this article, I list some little-known PHP functions that will make your eyes bright.

levenshtein()

Have you ever experienced the time when you need to know how different two words are? This function is here to help you solve this problem. It can compare the difference between two strings.

Usage:

<?php 
$str1 = "carrot"; 
$str2 = "carrrott"; 
echo levenshtein($str1, $str2); //Outputs 2 
?>

Source: http://php.net/manual/en/function.levenshtein.php

get_defined_vars()

This is a very useful function during debugging. This function returns a multidimensional array containing all defined variables.

Usage:

<?php 
print_r(get_defined_vars()); 
?>

Source: http://php.net/manual/en/function.get-defined-vars.php

php_check_syntax()

This function is very useful and can be used to check PHP Is the syntax correct? For technical reasons, this function has been removed starting with PHP 5.05.

Usage:

<?php 
$error_message = ""; 
$filename = "./php_script.php"; 
if(!php_check_syntax($filename, &$error_message)) { 
   echo "Errors were found in the file $filename: $error_message"; 
} else { 
   echo "The file $filename contained no syntax errors"; 
} 
?>

Source: http://www.php.net/manual/en/function.php-check-syntax.php

ignore_user_abort()

This function is used to refuse browser-side user termination A request to execute a script. Under normal circumstances, the client's exit will cause the server-side script to stop running.

Usage:

<?php 
ignore_user_abort(); 
?>

Source: http://www.php.net/manual/en/function.ignore-user-abort.php

highlight_string()

When you want to display PHP code on the page The highlight_string() function will be very useful. This function will highlight the PHP code you provide using the color defined by the built-in PHP syntax highlighting. This function has two parameters. The first parameter is a string, indicating that this string needs to be highlighted. If the second parameter is set to TRUE, this function will return the highlighted code as the return value.

Usage

<?php 
highlight_string(&#39; <?php phpinfo(); ?>&#39;); 
?>

Source: http://php.net/manual/en/function.highlight-string.php

highlight_file

This is a very useful PHP function that can return the specified PHP file, And highlight the file content with highlight colors according to syntax and semantics. The highlighted code is processed using HTML markup.

Usage:

<?php 
highlight_file("php_script.php"); 
?>

Source: http://www.php.net/manual/en/function.highlight-file.php

php_strip_whitespace

This function is also similar to the previous show_source() function, but it Comments and spaces in the file will be deleted.

Usage:

<?php 
echo php_strip_whitespace("php_script.php"); 
?>

Source: http://www.php.net/manual/en/function.php-strip-whitespace.php

get_browser

This function will read the browscap.ini file and return to browsing device compatibility information.

Usage:

<?php 
echo $_SERVER[&#39;HTTP_USER_AGENT&#39;]; 
$browser = get_browser(); 
print_r($browser); 
?>

Source: http://www.php.net/manual/en/function.get-browser.php

memory_get_usage(), memory_get_peak_usage(), getrusage()

These functions are used To obtain memory and CPU usage, the memory_get_usage() function returns the memory usage, the memory_get_peak_usage() function returns the peak memory usage, and getrusage() returns the CUP usage. These functions will provide you with some useful information when debugging PHP code performance. But please note that these functions are not valid on Windows.

Usage:

<?php 
echo "Initial: ".memory_get_usage()." bytes \n"; 
echo "Peak: ".memory_get_peak_usage()." bytes \n"; 
$data = getrusage(); 
echo "User time: ". 
    ($data[&#39;ru_utime.tv_sec&#39;] + 
    $data[&#39;ru_utime.tv_usec&#39;] / 1000000); 
echo "System time: ". 
    ($data[&#39;ru_stime.tv_sec&#39;] + 
    $data[&#39;ru_stime.tv_usec&#39;] / 1000000); 
 
?>

gzcompress(), gzuncompress()
These two functions are used to compress and decompress string data. Their compression rate can reach about 50%. The other functions gzencode() and gzdecode() can achieve similar results, but use different compression algorithms.

Usage:

<?php 
$string = 
"Lorem ipsum dolor sit amet, consectetur 
adipiscing elit. Nunc ut elit id mi ultricies 
adipiscing. Nulla facilisi. Praesent pulvinar, 
sapien vel feugiat vestibulum, nulla dui pretium orci, 
non ultricies elit lacus quis ante. Lorem ipsum dolor 
sit amet, consectetur adipiscing elit. Aliquam 
pretium ullamcorper urna quis iaculis. Etiam ac massa 
sed turpis tempor luctus. Curabitur sed nibh eu elit 
mollis congue. Praesent ipsum diam, consectetur vitae 
ornare a, aliquam a nunc. In id magna pellentesque 
tellus posuere adipiscing. Sed non mi metus, at lacinia 
augue. Sed magna nisi, ornare in mollis in, mollis 
sed nunc. Etiam at justo in leo congue mollis. 
Nullam in neque eget metus hendrerit scelerisque 
eu non enim. Ut malesuada lacus eu nulla bibendum 
id euismod urna sodales. "; 
 
$compressed = gzcompress($string); 
$original = gzuncompress($compressed); 
 
?>

Have you also thought of other useful functions? Please share it in the comments!