PHP built-in functions you don't know

PHP has a very rich built-in function, 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 degree of difference between two strings.

Usage:

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

?>

get_defined_vars()

This is very useful when debug debugging Useful functions. This function returns a multidimensional array, which contains all defined variables.

Usage:

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

php_check_syntax()

This function is very useful and can be used to check whether the syntax of PHP is correct. For technical reasons, this function has been removed starting from 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"; 
} 
?>

ignore_user_abort()

This function is used to reject the browser user’s request to terminate the execution of the script. . Under normal circumstances, the client's exit will cause the server-side script to stop running.

Usage:

<?php 
ignore_user_abort(); 
?>

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;); 
?>

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"); 
?>

php_strip_whitespace

This function is also similar to the previous

show_source() function Similar, but it removes comments and whitespace characters from the file.

Usage:

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

get_browser

This function will read the

browscap.ini file, Returns browser compatibility information.

Usage:

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

memory_get_usage(),memory_get_peak_usage(),getrusage()

These functions are used to obtain memory and CPU usage,

memory_get_usage()The function returns the memory usage, memory_get_peak_usage()The function returns the peak memory usage, getrusage() Returns CUP usage, these functions will give you 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); 

?>

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