Detailed explanation of PHP character settings in one article

In PHP programs, character setting is an important issue, involving character encoding, character set conversion, encoding conversion, and how to handle multiple languages. This article will introduce knowledge about character settings in PHP.

1. Character encoding

In computers, character encoding refers to encoding the characters in the character set into binary numbers, which are stored and transmitted in the computer. There are many encoding methods used by computers, among which common ones are ASCII, Unicode and UTF-8.

ASCII code: American Standard Code for Information Interchange, American Standard Code for Information Interchange. ASCII code is the earliest character encoding method. It specifies the encoding method of 128 characters, including 26 uppercase English letters, 26 lowercase English letters, 10 Arabic numerals and some symbols.

Unicode code: Unicode is a double-byte encoding, its purpose is to accommodate all characters, including Chinese, Japanese, Korean, European languages, etc. Unicode specifies the binary encoding of all symbols. Different characters can be represented by one or more binary encodings, so Unicode can represent all characters in the world.

UTF-8 encoding: UTF-8 is a variable-length Unicode encoding. UTF-8 uses one to four bytes to represent all Unicode symbols, and uses the length of bytes to represent the number of bits occupied. For ASCII characters, UTF-8 encoding requires only one byte, so the ASCII code is also part of the UTF-8 encoding.

2. Character encoding settings in PHP

In PHP, character encoding settings need to pay attention to the following aspects:

1. File encoding settings

First of all, make sure that the PHP file itself is saved in UTF-8 format. You can add the following statement to the header of the code file to declare the encoding:

<?php
header("Content-type:text/html; charset=utf-8");
?>

2. Database encoding settings

When PHP When an application needs to read and write a database, it needs to ensure that the table character set in the database is consistent with the connection character set. Under the MySQL database, you can set it with the following command:

SET NAMES UTF8;

3. Character set conversion function

PHP provides a variety of character set conversion functions, the common ones are mb_convert_encoding() and iconv ().

mb_convert_encoding() function: Convert a string from one character set to another. This function can be called by the following statement:

$string = mb_convert_encoding($string, "UTF-8", "GBK");

iconv() function: It also converts a To convert a character set's string into another character set, you can call this function through the following statement:

$string = iconv("GBK", "UTF-8", $string);

4. Multi-language processing

When you need to process multiple languages, you can use gettext( ) function, which can automatically translate content based on the user's language settings.

For example, the string "Hello, world!" needs to be translated into "Hello, world!" in the Chinese environment. This can be achieved through the following code:

// Specify location of translation tables
bindtextdomain("hello", "./locale");

// Choose domain
textdomain("hello");

// Print translated text
echo _("Hello, world!");

The above is the character encoding in PHP Knowledge of settings and reasonable character encoding settings will contribute to the robustness and scalability of PHP applications.

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