PHP String Functions

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
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