PHP training tutorial 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, the editor of Band of Brothers lists some PHP functions that are little known in PHP training but 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:

　　
　$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:

　　
　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 with PHP 5.05.

　 Usage:

　　
　$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"; .net/manual/en/function.php-check-syntax.php

　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:

​
​ignore_user_abort();

​?>

​highlight_string( )

　The highlight_string() function is very useful when you want to display PHP code on the page. 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

　　
　highlight_string('
'); file

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

Usage:

​ ​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 will delete comments and spaces in the file.

Usage:


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 browsercap.ini file and return browser compatibility information.

Usage:

 
 echo $_SERVER['HTTP_USER_AGENT'];
 $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. When debugging PHP code performance, these functions will provide you with Some useful information. But please note that these functions are not valid on Windows. $ data = getrusage( ); 

　　echo "User time: ". 

　　($data['ru_utime.tv_sec'] + 
　　$data['ru_utime.tv_usec'] / 1000000); 

　　echo "System time: ". 

($data['ru_stime.tv_sec'] +

　$data['ru_stime.tv_usec'] / 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： adipiscing. Nulla facilisi. Praesent pulvinar,

vestibulum, nulla dui pretium orci,

　non ultricies elit lacus quis ante. Lorem ipsum dolor

　sit amet, consectetur adipiscing elit.

　　sed turpis tempor luctus. Curabitur sed nibh eu elit

　mollis congue. Praesent ipsum diam, consectetur vitae

　ornare a, aliquam a nunc. augue. Sed magna nisi, ornare in mollis in, mollis

 sed nunc. Etiam at justo in leo congue mollis. dales. ";
　 $compressed = gzcompress($string);

　$original = gzuncompress($compressed);

　?>