The difference between characters and bytes in PHP and the conversion of strings and bytes into text

Characters in PHP are abstract entities that can be represented using a variety of different character schemes or code pages. Bytes are units that transmit information over the network (or store information on a hard disk or in memory). In this article, we also introduce the example of string and byte conversion in PHP, and look at the friends who are interested.

Character:

a character is an abstract entity that can be represented using a variety of different character schemes or code pages . For example, a Unicode UTF-16 encoding represents a character as a sequence of 16-bit integers, whereas a Unicode UTF-8 encoding represents the same character as a 8-bit byte sequence. The common language runtime uses Unicode UTF-16 (Unicode conversion format, 16-bit encoded form) to represent characters.

PHP under the UTF-8 encoding, a Chinese character accounted for 3 characters, GBK encoded only 2 characters.

Byte (byte):

Bytes are units that transmit information over the network (or store information on a hard disk or in memory).

Application:

If the table in the database is UTF8 encoded, the field is set to the maximum of 10 characters, and the max deposit length is eg: ' I am 1 '

Here's a look at the PHP string and byte conversion example

<?php/** * byte array with string conversion class */class Bytes {/** * Converts a string string to a byte array * @param $str the string to be converted * @param $bytes destination byte array * @author Zikie */public static function GetBytes ($string) {$bytes = array (); for ($i = 0; $i < strlen ($string); $i + +) {$ bytes[] = Ord ($string [$i]); } return $bytes; /** * Converts a byte array to a string type of data * @param $bytes byte array * @param $str target String * @return A String type of data */public static function toSt R ($bytes) {$str = '; foreach ($bytes as $ch) {$str. = Chr ($ch);} return $str;}/** * Converts an int to a byte array * @param $byt target by  Te Array * @param $val the string to be converted * */public static function integertobytes ($val) {$byt = array (); $byt [0] = ($val & 0xff); $BYT [1] = ($val >> 8 & 0xff); $BYT [2] = ($val >> & 0xff); $BYT [3] = ($val >> & 0xff); return $byt; }/** * Reads an integer type of data from the location specified in the byte array * @param $bytes byte array * @param $position the specified start position * @return An integer type of data */public stat IC function Bytestointeger ($bytes, $position) {$val = 0; $val = $bytes [$position + 3]& 0xFF; $val <<= 8; $val |= $bytes [$position + 2] & 0xFF; $val <<= 8; $val |= $bytes [$position + 1] & 0xFF; $val <<= 8; $val |= $bytes [$position] & 0xFF; return $val; }/** * Converts a shor string to a byte array * @param $byt destination byte array * @param $val the string to be converted * */public static function shorttobytes ($val) {$ byt = Array (); $byt [0] = ($val & 0xff); $BYT [1] = ($val >> 8 & 0xff); return $byt; /** * Reads a short type of data from the location specified in the byte array. * @param $bytes byte array * @param $position the specified start position * @return A short type of data */public static function Bytestoshort ($bytes, $posi tion) {$val = 0; $val = $bytes [$position + 1] & 0xFF; $val = $val << 8; $val |= $bytes [$position] & 0xFF; r Eturn $val; }}?>

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