Frequently Used PHP String Functions with Examples

Last Updated: 04 Sep, 2022

strlen()

This function is used to get the length of the given string. It accept single parameter and returns length of the string on success, and 0 if the string is empty.

Syntax: strlen(string)

Example:

<?php
$str = 'Hello guys';
echo strlen($str); // returns 10

$str = 'ABCD1234XYZ';
echo strlen($str); // returns 11
?>

strrev()

This function is used to reverse a given string. This function accepts single parameter.

Parameters:
string: Required parameter that specifies the string to be reversed

Syntax: strrev(string)

Example:

<?php
$str = "Hello friends";
echo strrev($str); // returns 'sdneirf olleH'
?>

substr()

This function is used to return the portion of the string specified by the offset and length parameters. It accept 3 parameters (string, start and length) and returns the string accordinglly.

Parameters:

string: Required parameter and specifies the string to return a part of.

start: Required parameter and specifies the start position in the string.

  • A positive number - Start at a specified position in the string
  • A negative number - Start at a specified position from the end of the string
  • 0 - Start at the first character in the string

lenght: Optional parameter and specifies the length of the returned string.

  • A positive number - The length to be returned from the start parameter position
  • A negative number - The lenght to be returned from the end of the string
  • 0, NULL or FALSE - Returns an empty string
Syntax: substr(string, start, lenght)

Example:

<?php
$str = 'Hello World';
echo substr($str, 1) . "<br>";
echo substr($str, 3, 2) . "<br>";
echo substr($str, 5, 3) . "<br>";
echo substr($str, -1, 2) . "<br>";
echo substr($str, 0, 5) . "<br>";
echo substr($str, -3, 3) . "<br>";
?>

Output:

ello World
lo
 Wo
d
Hello
rld

strtolower()

This function is used to convert the given string to the lowercase letter. It accept single parameter and.

Syntax: strtolower(string)

Example:

<?php
$str = 'Hello World';
echo strtolower($str); // returns hello world
?>

strtoupper()

This function is used to convert a given string to uppercase letter. It accepts single parameter.

Syntax: strtoupper(string)

Example:

<?php
$str = 'Hello World';
echo strtoupper($str); // returns HELLO WORLD
?>

ucfirst()

This function is used to convert the first character of a given string to uppercase letter. It accepts single parameter.

Syntax: ucfirst(string)

Example:

<?php
$str = 'hello World';
echo ucfirst($str); // returns Hello World
?>

lcfirst()

This function is used to convert the first character of a given string to lowercase letter. It accepts single parameter.

Syntax: lcfirst(string)

Example:

<?php
$str = 'Hello World';
echo lcfirst($str); // returns hello World
?>

ucwords()

This function is used to convert the first character of each word to uppercase letter. It accepts 2 parameters.

Parameters:
string: Required parameter and speifies the string to be converted
delimeters: Optional parameter and specifies the word separator character

Syntax: ucwords(string, delimeters)

Example:

<?php
$str = 'hello world';
echo ucwords($str, ' '); // returns Hello World
?>

trim()

This function is used to remove whitespace and any other predefined characters from the beginning and end of the string. This function accepts 2 parameters.

Parameters:
string: Required parameter that specifies the string to be checked
characters: Optional parameter that specifies which to remove from the string. If omitted, trim() will remove following characters:

  • "" - ordinary white space
  • "\t" - tab
  • "\n" - new line
  • "\r" - carriage return
  • "\v" - vertical tab
  • "\0" - NULL
Syntax: trim(string, characters)

Example:

<?php
$str = "This is a string ";
echo $str; // returns 'This is a string '
echo trim($str); // returns 'This is a string'
echo trim($str, 'ing '); // returns 'This is a str'
?>

ltrim()

This function is used to remove whitespace and any other predefined characters from the beginning of the string. This function accepts 2 parameters.

Parameters:
string: Required parameter that specifies the string to be checked
characters: Optional parameter that specifies which to remove from the string. If omitted, ltrim() will remove following characters:

  • "" - ordinary white space
  • "\t" - tab
  • "\n" - new line
  • "\r" - carriage return
  • "\v" - vertical tab
  • "\0" - NULL
Syntax: ltrim(string, characters)

Example:

<?php
$str = " This is a string";
echo ltrim($str); // returns 'This is a string'
echo ltrim($str, ' Th'); // returns 'is is a string'
?>

rtrim()

This function is used to remove whitespace and any other predefined characters from the end of the string. This function accepts 2 parameters.

Parameters:
string: Required parameter that specifies the string to be checked
characters: Optional parameter that specifies which to remove from the string. If omitted, rtrim() will remove following characters:
"" - ordinary white space
"\t" - tab
"\n" - new line
"\r" - carriage return
"\v" - vertical tab
"\0" - NULL

Syntax: rtrim(string, characters)

Example:

<?php
$str = " This is a string ";
echo rtrim($str); // returns ' This is a string'
echo rtrim($str, 'string '); // returns ' This is a'
?>

str_replace()

This function is used to replace all occurrences of the search string with the replacement string in a string. This function is case-sensitive, binary-safe and accepts 4 parameters. Please have a look on below given rules of this function:

  • If the string to be searched is an array, it returns an array
  • If the string to be searched is an array, it find and replace is performed on each array element
  • If both find and replace ara arrays, and replace has fewer elements than find, an empty string will be used as replace
  • If find is an array and replace is a string, the replace string will be used for every find value

Parameters:
search: Required parameter that specifies the value to search
replace: Required parameter that specifies the value to replace
subject: Required parameter that specifies the string/array to be searched
count: Optional parameter that counts the number of replacements

Syntax: str_replace(search, replace, subject, count)

Example:

<?php
$str = "Hello friends, how are you?";
echo str_replace('how', 'HOW', $str); // returns 'Hello friends, HOW are you?'

$arr = ['Ram', 'Shyam', 'Mohan', 'Girdhari', 'Gopal', 'Mohan'];
echo '\n';
print_r(str_replace('Mohan', 'Narayan', $arr, $count));
echo '\nReplacements: '.$count;

/* Output:
Array
(
    [0] => Ram
    [1] => Shyam
    [2] => Narayan
    [3] => Girdhari
    [4] => Gopal
    [5] => Narayan
)
Replacements: 2
*/
?>

Note: The str_replace() function is case-sensitive. If you want to ignore the case, use str_ireplace() instead.

str_split()

This function is used to split a string into an array. It accepts 2 parameters.

Parameters:
string: Required parameter that specifies the string to split
length: Optional parameter that specifies the length of each array element. Default value is 1. If less than 1, it will return FALSE; If larger than the length of string, the entire string will be returned as the only element of the array.

Syntax: str_split(string, length)

Example:

<?php
$str = "HiFriends";
print_r(str_split($str));
print_r(str_split($str, 3));
?>

Output:

Array
(
    [0] => H
    [1] => i
    [2] => F
    [3] => r
    [4] => i
    [5] => e
    [6] => n
    [7] => d
    [8] => s
)
Array
(
    [0] => HiF
    [1] => rie
    [2] => nds
)

str_repeat()

This function is used to repeat a string as many time as you specify. It accepts 2 parameters.

Parameters:
string: Required parameter that specifies the string to repeat
times: Required parameter that specifies the number of times the string to be repeated. It must be greater or equal to 0.

Syntax: str_repeat(string, times)

Example:

<?php
$str = "Hello ";
print_r(str_repeat($str, 10));

/*
Output:
Hello Hello Hello Hello Hello Hello Hello Hello Hello Hello
*/
?>

str_shuffle()

This function is used to randomly shuffle all the characters of a string. It accepts single parameter.

Parameters:
string: Required parameter that specifies the string to shuffle

Syntax: str_shuffle(string)

Example:

<?php
$str = "HelloFriends";
print_r(str_shuffle($str)); // returns like 'osirdFeenllH'
?>

strstr()

This function is used to search for the first occurence of a string inside another string. This function is case-sensitive, binary-safe and accepts 3 parameters.

Parameters:
string: Required parameter that specifies the string to search in
substring: Required parameter that specifies the string to search for
before_search: Optional boolean value, default is "false". If true, returns the part of the string before the first occurrence of the substring parameter.

Syntax: strstr(string, substring, before_search)

Example:

<?php
$str = 'Hello friends, I am your friend.';
echo strstr($str, 'friend'); // returns 'friends, I am your friend.'
echo strstr($str, 'friend', true); // returns 'Hello '
?>

strpos()

This function is used to find the position of the first occurence of a substring inside another string. This function is case-sensitive, binary-safe and accepts 3 parameters.

Parameters:

  • string: Required parameter that specifies the string to search in
  • substring: Required parameter that specifies the string to search for
  • offset: Optional parameter that specifies the search start position. If it is a negative number, it counts from the end of the string.
Syntax: strpos(string, substring, offset)

Example:

<?php
$str = 'Hello World';
echo strpos($str, 'll'); // returns 2
?>

stripos()

This function is used to find the position of the first occurence of a substring inside another string. This function is case-insensitive, binary-safe and accepts 3 parameters.

Parameters:
string: Required parameter that specifies the string to search in
substring: Required parameter that specifies the string to search for
offset: Optional parameter that specifies the search start position

Syntax: stripos(string, substring, offset)

Example:

<?php
$str = 'Hello World';
echo stripos($str, 'w'); // returns 6
?>

strrpos()

This function is used to find the position of the last occurence of a substring inside another string. This function is case-sensitive, binary-safe and accepts 3 parameters.

Parameters:
string: Required parameter that specifies the string to search in
substring: Required parameter that specifies the string to search for
offset: Optional parameter that specifies the search start position. If it is a negative number, it counts from the end of the string.

Syntax: strrpos(string, substring, offset)

Example:

<?php
$str = 'Hello World';
echo strrpos($str, 'o'); // returns 7
?>

strripos()

This function is used to find the position of the lst occurence of a substring inside another string. This function is case-insensitive, binary-safe and accepts 3 parameters.

Parameters:
string: Required parameter that specifies the string to search in
substring: Required parameter that specifies the string to search for
offset: Optional parameter that specifies the search start position

Syntax: strripos(string, substring, offset)

Example:

<?php
$str = 'Hello World';
echo strripos($str, 'L'); // returns 9
?>

 

 

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