PHP String Functions

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PHP String Introduction
　　The string functions allow you to manipulate strings.
Installation
　　The string functions are part of the PHP core. There is no installation needed to use these functions.
PHP String Functions
　　PHP: indicates the earliest version of PHP that supports the function.
FunctionDescriptionPHPaddcslashes()Returns a string with backslashes in front of the specified characters4addslashes()Returns a string with backslashes in front of predefined characters3bin2hex()Converts a string of ASCII characters to hexadecimal values3chop()Alias of rtrim()3chr()Returns a character from a specified ASCII value3chunk_split()Splits a string into a series of smaller parts3convert_cyr_string()Converts a string from one Cyrillic character-set to another3convert_uudecode()Decodes a uuencoded string5convert_uuencode()Encodes a string using the uuencode algorithm5count_chars()Returns how many times an ASCII character occurs within a string and returns the information4crc32()Calculates a 32-bit CRC for a string4crypt()One-way string encryption (hashing)3echo()Outputs strings3explode()Breaks a string into an array3fprintf()Writes a formatted string to a specified output stream5get_html_translation_table()Returns the translation table used by htmlspecialchars() and htmlentities()4hebrev()Converts Hebrew text to visual text3hebrevc()Converts Hebrew text to visual text and new lines (\n) into <br />3html_entity_decode()Converts HTML entities to characters4htmlentities()Converts characters to HTML entities3htmlspecialchars_decode()Converts some predefined HTML entities to characters5htmlspecialchars()Converts some predefined characters to HTML entities3implode()Returns a string from the elements of an array3join()Alias of implode()3levenshtein()Returns the Levenshtein distance between two strings3localeconv()Returns locale numeric and monetary formatting information4ltrim()Strips whitespace from the left side of a string3md5()Calculates the MD5 hash of a string3md5_file()Calculates the MD5 hash of a file4metaphone()Calculates the metaphone key of a string4money_format()Returns a string formatted as a currency string4nl_langinfo()Returns specific local information4nl2br()Inserts HTML line breaks in front of each newline in a string3number_format()Formats a number with grouped thousands3ord()Returns the ASCII value of the first character of a string3parse_str()Parses a query string into variables3print()Outputs a string3printf()Outputs a formatted string3quoted_printable_decode()Decodes a quoted-printable string3quotemeta()Quotes meta characters3rtrim()Strips whitespace from the right side of a string3setlocale()Sets locale information3sha1()Calculates the SHA-1 hash of a string4sha1_file()Calculates the SHA-1 hash of a file4similar_text()Calculates the similarity between two strings3soundex()Calculates the soundex key of a string3sprintf()Writes a formatted string to a variable3sscanf()Parses input from a string according to a format4str_ireplace()Replaces some characters in a string (case-insensitive)5str_pad()Pads a string to a new length4str_repeat()Repeats a string a specified number of times4str_replace()Replaces some characters in a string (case-sensitive)3str_rot13()Performs the ROT13 encoding on a string4str_shuffle()Randomly shuffles all characters in a string4str_split()Splits a string into an array5str_word_count()Count the number of words in a string4strcasecmp()Compares two strings (case-insensitive)3strchr()Finds the first occurrence of a string inside another string (alias of strstr())3strcmp()Compares two strings (case-sensitive)3strcoll()Locale based string comparison4strcspn()Returns the number of characters found in a string before any part of some specified characters are found3strip_tags()Strips HTML and PHP tags from a string3stripcslashes()Unquotes a string quoted with addcslashes()4stripslashes()Unquotes a string quoted with addslashes()3stripos()Returns the position of the first occurrence of a string inside another string (case-insensitive)5stristr()Finds the first occurrence of a string inside another string (case-insensitive)3strlen()Returns the length of a string3strnatcasecmp()Compares two strings using a "natural order" algorithm (case-insensitive)4strnatcmp()Compares two strings using a "natural order" algorithm (case-sensitive)4strncasecmp()String comparison of the first n characters (case-insensitive)4strncmp()String comparison of the first n characters (case-sensitive)4strpbrk()Searches a string for any of a set of characters5strpos()Returns the position of the first occurrence of a string inside another string (case-sensitive)3strrchr()Finds the last occurrence of a string inside another string3strrev()Reverses a string3strripos()Finds the position of the last occurrence of a string inside another string (case-insensitive)5strrpos()Finds the position of the last occurrence of a string inside another string (case-sensitive)3strspn()Returns the number of characters found in a string that contains only characters from a specified charlist3strstr()Finds the first occurrence of a string inside another string (case-sensitive)3strtok()Splits a string into smaller strings3strtolower()Converts a string to lowercase letters3strtoupper()Converts a string to uppercase letters3strtr()Translates certain characters in a string3substr()Returns a part of a string3substr_compare()Compares two strings from a specified start position (binary safe and optionally case-sensitive)5substr_count()Counts the number of times a substring occurs in a string4substr_replace()Replaces a part of a string with another string4trim()Strips whitespace from both sides of a string3ucfirst()Converts the first character of a string to uppercase3ucwords()Converts the first character of each word in a string to uppercase3vfprintf()Writes a formatted string to a specified output stream5vprintf()Outputs a formatted string4vsprintf()Writes a formatted string to a variable4wordwrap()Wraps a string to a given number of characters4
PHP String Constants
　　PHP: indicates the earliest version of PHP that supports the constant.
ConstantDescriptionPHPCRYPT_SALT_LENGTHContains the length of the default encryption method for the
system. For standard DES encryption, the length is 2 CRYPT_STD_DESSet to 1 if the standard DES-based encryption with a 2 character salt is supported, 0 otherwise CRYPT_EXT_DESSet to 1 if the extended DES-based encryption with a 9 character salt is supported, 0 otherwise CRYPT_MD5Set to 1 if the MD5 encryption with a 12 character salt starting with $1$ is supported, 0 otherwise CRYPT_BLOWFISHSet to 1 if the Blowfish encryption with a 16 character salt starting with $2$ or $2a$ is supported, 0 otherwise0 HTML_SPECIALCHARS  HTML_ENTITIES  ENT_COMPAT  ENT_QUOTES  ENT_NOQUOTES  CHAR_MAX  LC_CTYPE  LC_NUMERIC  LC_TIME  LC_COLLATE  LC_MONETARY  LC_ALL  LC_MESSAGES  STR_PAD_LEFT  STR_PAD_RIGHT  STR_PAD_BOTH