PHP String Functions Complete Reference
Last Updated :
12 Jul, 2025
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Strings are a collection of characters. For example, 'G' is the character and 'GeeksforGeeks' is the string.
Installation: These functions are not required any installation. These are the part of PHP core. The complete list of PHP string functions are given below:
Example: This program helps us to calculate a 32-bit CRC for the string “Hello World”, both with %u and without %u.
<?php
// PHP program illustrate the
// crc32() function
$str1 = crc32("Hello world.");
// print without %u
echo 'Without %u: '.$str1."\n";
// print with %u
echo 'With %u: ';
printf("%u\n", $str1);
?>
Output:
Without %u: 2335835140 With %u: 2335835140
The complete list of String Functions are given below:
PHP String Functions | Description | Example |
|---|---|---|
| addcslashes() | Add backslashes before some specified characters in a given string. | |
| addslashes() | Returns a string with backslashes in front of predefined characters. | |
| bin2hex() | The conversion is done byte-wise with the high-nibble first. | |
| chop() | Remove white spaces or any other specified characters from the end of a string. | |
| chr() | Convert a ASCII value to a character. | |
| chunk_split() | Split a string into smaller chunks of a specific length. | |
| convert_uudecode() | Decode a uuencoded string encoded using convert_uuencode() function. | |
| convert_uuencode() | Encodes a string using the uuencode algorithm. | |
| count_chars() | Perform several operations related to string like the number of an ASCII character occurs in a string. | |
| crc32() | This function can be used to validate data integrity. | |
| PHP crypt() | Returns a hashed string using DES, Blowfish, or MD5 algorithms. | |
| password_hash() | Returns the hashed string on success or FALSE | |
| echo | Display the output of parameters that are passed to it. | |
| explode() | Explode() function splits a string based on a string delimiter | |
| hex2bin() | Decode a hexadecimally encoded binary string. | |
| implode() | Elements of an array. implode() is an alias for PHP | |
| join() | Join an array of elements that are separated by a string. | |
| lcfirst() | It takes a string as an argument | |
| levenshtein() | Calculate the levenshtein distance between two strings | |
| ltrim() | Removes whitespaces or other characters | |
| md5_file() | Generate the md5 hash value of a given file. | |
| md5() | This function can take up to a maximum of two parameters | |
| metaphone() | Calculate the metaphone key of a given string. | |
| nl2br() | Insert HTML break tags in the place of all new lines in a string. | |
| number_format() | Format a number with grouped thousands. | |
| ord() | Returns the ASCII value of the first character of a string | |
| parse_str() | parse_str() function is a built-in function in PHP which parses a query string into variables. | |
| quoted_printable_decode() | Decode a quoted printable string in PHP into an 8-bit string. | |
| quoted_printable_encode() | Convert an 8-bit string to a quoted printable string. | |
| quotemeta() | Accepts a string as an argument and returns a string | |
| rtrim() | Removes whitespaces or other characters (if specified) from the right side of a string. | |
| sha1_file() | Returns a string on success and returns FALSE otherwise. | |
| sha1() | This function an take up to a maximum of two parameters | |
| similar_text() | Returns the number of matching characters in the two strings. | |
| soundex() | Calculate the Soundex key of a given string. | |
| str_pad() | Pad a string to a given length. | |
| str_repeat() | Create a new string by repeating a given string fixed number of times. | |
| str_replace() | Replace all the occurrences of the search string or array of search strings | |
| str_rot13() | Accepts a string and shifts every alphabet present in the string by 13 places in the alphabet | |
| str_shuffle() | Randomly shuffle all the characters of a string passed to the function as a parameter. | |
| str_split() | Convert the given string into an array. | |
| str_word_count() | String like total number word in the string, positions of the words in the string etc. | |
| strcasecmp() | This is used to compare two given strings. | |
| strchr() | Search for the first occurrence of a given string | |
| strcmp() | It is used to compare two strings | |
| strcoll() | It is used to compare two strings. | |
| strcspn() | Returns the number of characters present in a string | |
| strip_tags() | This is used to strips a string from HTML, and PHP tags. | |
| stripos() | Find the position of the first occurrence of a string in another string. | |
| stripslashes() | Removes backslashes in a string. | |
| stristr() | It searches for the first occurrence of a string inside another string and displays the portion | |
| strlen() | It takes a string as a parameter and returns its length. | |
| strnatcasecmp() | This function is similar to strnatcmp()only difference being the (case-insensitivity). | |
| strnatcmp() | Return a positive integer, negative, or zero. | |
| strncasecmp() | Compare two given strings. It is case-insensitive. | |
| strncmp() | Compare the first n character of two strings. | |
| strpbrk() | Searches a string for any of the specified characters. | |
| strpos() | Find the position of the first occurrence of a string in another string. | |
| strrchr() | This function takes two arguments a string and a character. | |
| strrev() | It is used to reverse a string. | |
| strripos() | Out of the three parameters specified in the syntax, two are mandatory and one is optional | |
| strrpos() | Out of the three parameters specified in the syntax, two are mandatory and one is optional. | |
| strspn() | Finds the length of the initial segment of a string | |
| strstr() | It searches for the first occurrence of a string inside another string and displays the portion | |
| strtok() | Tokenize a string into smaller parts on the basis of given delimiters | |
| strtolower() | Convert a string into lowercase. | |
| strtoupper() | Convert a string into uppercase | |
| strtr() | Replace a substring in a string to a given string of characters. | |
| substr_compare() | Compare two strings from a specified start position upto a specified length. | |
| substr_count() | Count the number of times a substring occurs in a given string. | |
| substr_replace() | Replace a part of a string with another string. | |
| substr() | That is used to extract a part of a string. | |
| trim() | Removes whitespaces and also the predefined characters from both sides. | |
| ucfirst() | Takes a string as an argument and returns the string | |
| ucwords() | Convert the first character of every word in a string to upper-case. | |
| vprintf() | Display array values as a formatted string | |
| vsprintf() | Display array values as a formatted string. | |
| wordwrap() | Wraps a given string to a given number of characters using a string break character. |
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