Summary of commonly used functions and global variables in PHP (recommended)

This article introduces to you a summary (recommended) of commonly used functions and global variables in PHP. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

1. PHP built-in function

A

array_shift() deletes the first element in the array

array_pop() Delete the last element in the array

array_multisort() Return an ascending array

C

call_user_func_array() Call the callback function, and Call an array as a parameter of the callback function

D

define() define constant

debug_backtrace() trace code call information

E

error_reporting(0) Turn off error reporting

error_reporting(E_ERROR | E_WARNING | E_PARSE) Report runtime errors

error_reporting(E_ALL) Report all errors

ini_set("error_reporting", E_ALL) Equivalent to error_reporting(E_ALL)

error_reporting(E_ALL & ~E_NOTICE) Reports all errors except E_NOTICE

explode() will Split the string into an array

implode() Splice the elements in the array into a string

G

1.getenv() Get the value of the environment variable

$_SERVER['HTTP_HOST'] = getenv('HTTP_HOST');

H

header() Sends the original HTTP header to the client

I

is_file() Determines whether it is a file

ini_get() Gets the value of a configuration option

is_set() Whether it has been defined

is_null() Whether it is empty

P

1. phpversion() Current PHP version

R

require_once() Loading File

S

str_replace() Replace some characters in a string with other characters (case sensitive)

strlen() Get a string Length

substr() Return part of the string

str_repalce() Replace part of the string with another part

strtolower() Convert to lowercase

spl_autoload_register() Automatic loading

spl_autoload_extensions() Returns the automatically loaded file extension

U

unset() Destroy

V

1. version_compare( string $version1 , string $version2 [, string $operator ] ) Compare the first version number of PHP version

version1. version2 The second version number operator operator <, lt, <=, le, >、 gt、>=、 ge、==、 =、eq , !=, <> and ne

For example:

if (version_compare(phpversion(), &#39;5.6.0&#39;, &#39;<&#39;)) {
	exit(&#39;PHP5.6+ Required&#39;);
}

2. Super global variables

$_SERVER

$_SERVER['DOCUMENT_ROOT']; The document root where the currently running script is located

$_SERVER['DOCUMENT_FILENAME'] The absolute path of the currently executing script

$_SERVER['PHP_SELF'] The file name of the currently executing script

$_SERVER['HTTP_HOST'] Get the current host

$_SERVER['PATH_TRANSLATED'] The base path where the current script is located, non-document root directory

$_SERVER['REQUEST_URI'] The current request path

$ _SERVER['QUERY_STRING'] Query string

$_SERVER['SERVER_PORT'] Server port

$_SERVER['HTTPS'] HTTPS request

Type operator

instanceof Determines whether a variable is an instance of a class

3. Common PHP encapsulated functions:

1. Determination Is it an HTTPS request?

// 检查是否是HTTPS请求
if ((isset($_SERVER['HTTPS']) && (($_SERVER['HTTPS'] == 'on') || ($_SERVER['HTTPS'] == '1'))) || (isset($_SERVER['HTTPS']) && (isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == 443))) {
    $_SERVER['HTTPS'] = true;
} elseif (!empty($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https' || !empty($_SERVER['HTTP_X_FORWARDED_SSL']) && $_SERVER['HTTP_X_FORWARDED_SSL'] == 'on') {
    $_SERVER['HTTPS'] = true;
} else {
    $_SERVER['HTTPS'] = false;
}

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