PHP String Functions

From http://www.w3schools.com (Copyright Refsnes Data)

# PHP String Functions

## 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.

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

## 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 |  |

From http://www.w3schools.com (Copyright Refsnes Data)