7 practical PHP built-in function recommendations

This article recommends 7 php built-in functions that are not often used, but are actually very practical and powerful. If you use them well, you can save a lot of time.

PHP has many built-in functions, most of which are widely used by programmers. But there are also some functions hidden in the corners. This article will introduce to you 7 functions that are little known but very useful. Programmers who have never used it may wish to come and take a look.

　1.highlight_string()

When you need to display PHP code in a website, the highlight_string() function changes Very useful. This function outputs or returns a syntax-highlighted version of the given PHP code, using the colors defined in the PHP syntax highlighter.

Example:

The code is as follows:

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

2.str_word_count()

This function must To pass a parameter, return the number of words according to the parameter type. As shown below:

The code is as follows:

<?php
$str = "How many words do I have?";
echo str_word_count($str); //Outputs 6
?>

　3.levenshtein()

This function mainly returns the Levenshtein distance between two

strings. Levenshtein distance, also known as edit distance, refers to the minimum number of edit operations required between two strings to convert one into the other. Permitted editing operations include replacing one character with another, inserting a character, and deleting a character. This function is useful for finding typos submitted by users.

Example:

The code is as follows:

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

4.get_defined_vars()

This function returns a list containing all

Define variablesMultidimensional array of the list, these variables include environment variables, server variables and user-defined variables. Example:

The code is as follows:

print_r(get_defined_vars());

5.escapeshellcmd()

This function uses To avoid special symbols in the string, it can prevent users from playing tricks to crack the server system. You can use this function with the exec() or system() functions, which can reduce the malicious destructive behavior of online users.

Example:

The code is as follows:

<?php
$command = &#39;./configure &#39;.$_POST[&#39;configure_options&#39;];
$escaped_command = escapeshellcmd($command);
system($escaped_command);
?>

6.checkdate()

This function can be used to check whether the date is valid , for example, the year ranges from 0 to 32767, the month ranges from January to December, and the day changes with the month and leap year.

Example:

The code is as follows:

<?php
var_dump(checkdate(12, 31, 2000));
var_dump(checkdate(2, 29, 2001));
//Output
//bool(true)
//bool(false)
?>

7.php_strip_whitespace()

This function can Returns the source code file with

PHP comments

and whitespace characters removed, which is useful for comparing the actual number of code and the number of comments. Example:

The code is as follows:

<?php
// PHP comment here
/*
 * Another PHP comment
 */
echo        php_strip_whitespace(FILE);
// Newlines are considered whitespace, and are removed too:
do_nothing();
?>

Output result:

The code is as follows:

<?php 
echo php_strip_whitespace(FILE); do_nothing(); 
?>

How many of the above 7 built-in functions of PHP have you used?

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