PHP String Functions

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PHP String Introduction

The string functions allow you to manipulate strings.

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Installation

The string functions are part of the PHP core. There is no installation needed to use these functions.

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PHP String Functions

PHP: indicates the earliest version of PHP that supports the function.

Function	Description	PHP
addcslashes()	Returns a string with backslashes in front of the specified characters	4
addslashes()	Returns a string with backslashes in front of predefined characters	3
bin2hex()	Converts a string of ASCII characters to hexadecimal values	3
chop()	Alias of rtrim()	3
chr()	Returns a character from a specified ASCII value	3
chunk_split()	Splits a string into a series of smaller parts	3
convert_cyr_string()	Converts a string from one Cyrillic character-set to another	3
convert_uudecode()	Decodes a uuencoded string	5
convert_uuencode()	Encodes a string using the uuencode algorithm	5
count_chars()	Returns how many times an ASCII character occurs within a string and returns the information	4
crc32()	Calculates a 32-bit CRC for a string	4
crypt()	One-way string encryption (hashing)	3
echo()	Outputs strings	3
explode()	Breaks a string into an array	3
fprintf()	Writes a formatted string to a specified output stream	5
get_html_translation_table()	Returns the translation table used by htmlspecialchars() and htmlentities()	4
hebrev()	Converts Hebrew text to visual text	3
hebrevc()	Converts Hebrew text to visual text and new lines (\n) into <br />	3
html_entity_decode()	Converts HTML entities to characters	4
htmlentities()	Converts characters to HTML entities	3
htmlspecialchars_decode()	Converts some predefined HTML entities to characters	5
htmlspecialchars()	Converts some predefined characters to HTML entities	3
implode()	Returns a string from the elements of an array	3
join()	Alias of implode()	3
levenshtein()	Returns the Levenshtein distance between two strings	3
localeconv()	Returns locale numeric and monetary formatting information	4
ltrim()	Strips whitespace from the left side of a string	3
md5()	Calculates the MD5 hash of a string	3
md5_file()	Calculates the MD5 hash of a file	4
metaphone()	Calculates the metaphone key of a string	4
money_format()	Returns a string formatted as a currency string	4
nl_langinfo()	Returns specific local information	4
nl2br()	Inserts HTML line breaks in front of each newline in a string	3
number_format()	Formats a number with grouped thousands	3
ord()	Returns the ASCII value of the first character of a string	3
parse_str()	Parses a query string into variables	3
print()	Outputs a string	3
printf()	Outputs a formatted string	3
quoted_printable_decode()	Decodes a quoted-printable string	3
quotemeta()	Quotes meta characters	3
rtrim()	Strips whitespace from the right side of a string	3
setlocale()	Sets locale information	3
sha1()	Calculates the SHA-1 hash of a string	4
sha1_file()	Calculates the SHA-1 hash of a file	4
similar_text()	Calculates the similarity between two strings	3
soundex()	Calculates the soundex key of a string	3
sprintf()	Writes a formatted string to a variable	3
sscanf()	Parses input from a string according to a format	4
str_ireplace()	Replaces some characters in a string (case-insensitive)	5
str_pad()	Pads a string to a new length	4
str_repeat()	Repeats a string a specified number of times	4
str_replace()	Replaces some characters in a string (case-sensitive)	3
str_rot13()	Performs the ROT13 encoding on a string	4
str_shuffle()	Randomly shuffles all characters in a string	4
str_split()	Splits a string into an array	5
str_word_count()	Count the number of words in a string	4
strcasecmp()	Compares two strings (case-insensitive)	3
strchr()	Finds the first occurrence of a string inside another string (alias of strstr())	3
strcmp()	Compares two strings (case-sensitive)	3
strcoll()	Locale based string comparison	4
strcspn()	Returns the number of characters found in a string before any part of some specified characters are found	3
strip_tags()	Strips HTML and PHP tags from a string	3
stripcslashes()	Unquotes a string quoted with addcslashes()	4
stripslashes()	Unquotes a string quoted with addslashes()	3
stripos()	Returns the position of the first occurrence of a string inside another string (case-insensitive)	5
stristr()	Finds the first occurrence of a string inside another string (case-insensitive)	3
strlen()	Returns the length of a string	3
strnatcasecmp()	Compares two strings using a "natural order" algorithm (case-insensitive)	4
strnatcmp()	Compares two strings using a "natural order" algorithm (case-sensitive)	4
strncasecmp()	String comparison of the first n characters (case-insensitive)	4
strncmp()	String comparison of the first n characters (case-sensitive)	4
strpbrk()	Searches a string for any of a set of characters	5
strpos()	Returns the position of the first occurrence of a string inside another string (case-sensitive)	3
strrchr()	Finds the last occurrence of a string inside another string	3
strrev()	Reverses a string	3
strripos()	Finds the position of the last occurrence of a string inside another string (case-insensitive)	5
strrpos()	Finds the position of the last occurrence of a string inside another string (case-sensitive)	3
strspn()	Returns the number of characters found in a string that contains only characters from a specified charlist	3
strstr()	Finds the first occurrence of a string inside another string (case-sensitive)	3
strtok()	Splits a string into smaller strings	3
strtolower()	Converts a string to lowercase letters	3
strtoupper()	Converts a string to uppercase letters	3
strtr()	Translates certain characters in a string	3
substr()	Returns a part of a string	3
substr_compare()	Compares two strings from a specified start position (binary safe and optionally case-sensitive)	5
substr_count()	Counts the number of times a substring occurs in a string	4
substr_replace()	Replaces a part of a string with another string	4
trim()	Strips whitespace from both sides of a string	3
ucfirst()	Converts the first character of a string to uppercase	3
ucwords()	Converts the first character of each word in a string to uppercase	3
vfprintf()	Writes a formatted string to a specified output stream	5
vprintf()	Outputs a formatted string	4
vsprintf()	Writes a formatted string to a variable	4
wordwrap()	Wraps a string to a given number of characters	4

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PHP String Constants

PHP: indicates the earliest version of PHP that supports the constant.

Constant	Description	PHP
CRYPT_SALT_LENGTH	Contains the length of the default encryption method for the system. For standard DES encryption, the length is 2
CRYPT_STD_DES	Set to 1 if the standard DES-based encryption with a 2 character salt is supported, 0 otherwise
CRYPT_EXT_DES	Set to 1 if the extended DES-based encryption with a 9 character salt is supported, 0 otherwise
CRYPT_MD5	Set to 1 if the MD5 encryption with a 12 character salt starting with $1$ is supported, 0 otherwise
CRYPT_BLOWFISH	Set 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

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