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Multibyte String

Introduction

While there are many languages in which every necessary character can be represented by a one-to-one mapping to an 8-bit value, there are also several languages which require so many characters for written communication that they cannot be contained within the range a mere byte can code (A byte is made up of eight bits. Each bit can contain only two distinct values, one or zero. Because of this, a byte can only represent 256 unique values (two to the power of eight)). Multibyte character encoding schemes were developed to express more than 256 characters in the regular bytewise coding system.

When you manipulate (trim, split, splice, etc.) strings encoded in a multibyte encoding, you need to use special functions since two or more consecutive bytes may represent a single character in such encoding schemes. Otherwise, if you apply a non-multibyte-aware string function to the string, it probably fails to detect the beginning or ending of the multibyte character and ends up with a corrupted garbage string that most likely loses its original meaning.

mbstring provides multibyte specific string functions that help you deal with multibyte encodings in PHP. In addition to that, mbstring handles character encoding conversion between the possible encoding pairs. mbstring is designed to handle Unicode-based encodings such as UTF-8 and UCS-2 and many single-byte encodings for convenience (listed in Supported Character Encodings).

Installing/Configuring
- Installation
- Runtime Configuration
Predefined Constants
Summaries of supported encodings
Basics of Japanese multi-byte encodings
HTTP Input and Output
Supported Character Encodings
Function Overloading Feature
PHP Character Encoding Requirements
Multibyte String Functions
- mb_check_encoding Check if strings are valid for the specified encoding
- mb_chr Return character by Unicode code point value
- mb_convert_case Perform case folding on a string
- mb_convert_encoding Convert a string from one character encoding to another
- mb_convert_kana Convert "kana" one from another ("zen-kaku", "han-kaku" and more)
- mb_convert_variables Convert character code in variable(s)
- mb_decode_mimeheader Decode string in MIME header field
- mb_decode_numericentity Decode HTML numeric string reference to character
- mb_detect_encoding Detect character encoding
- mb_detect_order Set/Get character encoding detection order
- mb_encode_mimeheader Encode string for MIME header
- mb_encode_numericentity Encode character to HTML numeric string reference
- mb_encoding_aliases Get aliases of a known encoding type
- mb_ereg Regular expression match with multibyte support
- mb_ereg_match Regular expression match for multibyte string
- mb_ereg_replace Replace regular expression with multibyte support
- mb_ereg_replace_callback Perform a regular expression search and replace with multibyte support using a callback
- mb_ereg_search Multibyte regular expression match for predefined multibyte string
- mb_ereg_search_getpos Returns start point for next regular expression match
- mb_ereg_search_getregs Retrieve the result from the last multibyte regular expression match
- mb_ereg_search_init Setup string and regular expression for a multibyte regular expression match
- mb_ereg_search_pos Returns position and length of a matched part of the multibyte regular expression for a predefined multibyte string
- mb_ereg_search_regs Returns the matched part of a multibyte regular expression
- mb_ereg_search_setpos Set start point of next regular expression match
- mb_eregi Regular expression match ignoring case with multibyte support
- mb_eregi_replace Replace regular expression with multibyte support ignoring case
- mb_get_info Get internal settings of mbstring
- mb_http_input Detect HTTP input character encoding
- mb_http_output Set/Get HTTP output character encoding
- mb_internal_encoding Set/Get internal character encoding
- mb_language Set/Get current language
- mb_lcfirst Make a string's first character lowercase
- mb_list_encodings Returns an array of all supported encodings
- mb_ltrim Strip whitespace (or other characters) from the beginning of a string
- mb_ord Get Unicode code point of character
- mb_output_handler Callback function converts character encoding in output buffer
- mb_parse_str Parse GET/POST/COOKIE data and set global variable
- mb_preferred_mime_name Get MIME charset string
- mb_regex_encoding Set/Get character encoding for multibyte regex
- mb_regex_set_options Set/Get the default options for mbregex functions
- mb_rtrim Strip whitespace (or other characters) from the end of a string
- mb_scrub Replace ill-formed byte sequences with the substitute character
- mb_send_mail Send encoded mail
- mb_split Split multibyte string using regular expression
- mb_str_pad Pad a multibyte string to a certain length with another multibyte string
- mb_str_split Given a multibyte string, return an array of its characters
- mb_strcut Get part of string
- mb_strimwidth Get truncated string with specified width
- mb_stripos Finds position of first occurrence of a string within another, case insensitive
- mb_stristr Finds first occurrence of a string within another, case insensitive
- mb_strlen Get string length
- mb_strpos Find position of first occurrence of string in a string
- mb_strrchr Finds the last occurrence of a character in a string within another
- mb_strrichr Finds the last occurrence of a character in a string within another, case insensitive
- mb_strripos Finds position of last occurrence of a string within another, case insensitive
- mb_strrpos Find position of last occurrence of a string in a string
- mb_strstr Finds first occurrence of a string within another
- mb_strtolower Make a string lowercase
- mb_strtoupper Make a string uppercase
- mb_strwidth Return width of string
- mb_substitute_character Set/Get substitution character
- mb_substr Get part of string
- mb_substr_count Count the number of substring occurrences
- mb_trim Strip whitespace (or other characters) from the beginning and end of a string
- mb_ucfirst Make a string's first character uppercase

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