Basic functions for working with string in PHP. Example of use

Examples of strings:

$str = ' Hello, world! ';
$str2 = 'Hello, world!';
$str3 = "<script>alert('©Hello &gt;' + \" world\")</script>";
$str4 = "Hi!\nIn first...";

1. strlen — returns the length of the string:

strlen($str);//will return the number of bytes, not the number of characters in the string.

2. explode — split a string using a delimiter:

explode(',', $str2);//the first parameter is a delimiter and the second is a string
//returns an array of strings,

3. implode — concatenates the elements of an array into a string:

implode(',', $data);//creates an array with strings where each element of the array is separated by ","
//returns string

4. htmlspecialchars — Convert special characters to HTML entities:

htmlspecialchars($str3, ENT_QUOTES, double_encode: false);//read a documentation - https://www.php.net/manual/ru/function.htmlspecialchars.php

5. ltrim – remove spaces (or other characters) from the beginning of a string

ltrim($str);return string without charecters on beginning

6. rtrim – remove spaces (or other characters) from the end of a string

rtrim($str);return string without charecters on the end

7. trim — removes spaces (or other characters) from the beginning and end of a string

trim($str, 'H ');//delete all "H" characters from the string, and if 2 is not specified, remove spaces (or another characters) from the beginning and end of the string.

8. nl2br — inserts an HTML line break code before each newline

nl2br($str4);//Returns a string with a <br /> or <br> inserted before each newline (\r\n, \n\r, \n, and \r).

9. str_split — converts a string to an array

str_split($str));//return the array for each element and the array for the symbols for the string
//In 2-th parameter we can specify the length of each element of the array

10. strpos – Returns the position of the first occurrence of a substring

strpos('abc', 'a');//returns 0. If the search string is not found, returns false

11. stripos – returns the position of the first occurrence of a substring, case insensitive

stripos('abc', 'a');//used to find the first occurrence of a substring in a string, case insensitive

12. strtolower – converts a string to lowercase

strtolower($str);//returns the string with all lowercase characters

13. strtoupper – сonverts a string to uppercase

strtoupper($str);//returns the string with all uppercase characters

14. substr– returns a substring

substr($str, -3, 1);//substr(string $string, int $offset, ?int $length = null)://returns a substring of string starting at offset character count and length characters long.