strings in php

A string is series of characters. For example ‘C’ is a character and ‘Cyber Teak’ is a string. Everything inside quotes, single (‘ ’) and double (“ ”) in PHP is treated as a string.

A string literal can be specified in two different ways:

1. Single-quote strings: Single quite type of string does not processes special characters inside quotes.

Example:

<?php

            //Single-quote string

            $var = ‘Welcome in Cyber Teak’;

            echo $var;

?>

2. Double-quote strings: If the string is enclosed in double-quotes ("), PHP will process the following escape sequences for special characters like “\n”, “\t”, etc.

 Example:

<?php

            // double-quote strings

            echo “Welcome in \n”;

            $var = “cyberteak.com”;

            echo $var;

            echo “Welcome in $var”;

?>

Some frequently used special characters that are used with double-quote strings.

1. “\n” is replaced by a new line
2. “\t” is replaced by a tab space
3. “\$” is replaced by a dollar sign
4. “\r” is replaced by a carriage return
5. “\\” is replaced by a backslash
6. “\”” is replaced by a double quote
7. “\’” is replaced by a single quote

String Functions

Built in functions in PHP are some existing library functions which can used directly in our programs making an appropriate call to them.

1. strlen() function: This function is used to find the length of a string. This function is take the string as argument and return the length. Mean return number of characters in the string.

Example:

<?php

            echo strlen(“Hello Cyber Teak”); // output 16

?>

2. strrev() function: This function is used to reverse a string. This function accept a string as argument and returns its reversed string.

Example:

<?php

            echo strrev(“Hello CyberTeak!”);  // output !kaeT rebyC olleH

?>

3. str_word_count() function:The PHP str_word_count() function counts the number of words in a string.

Example:

<?php

echo str_word_count("Cyber Teak!"); // outputs 2

?>

4. strpos() function:The PHP strpos() function searches for a specific text within a string.

Example:

<?php

echo strpos("Cyber Teak!", "Teak"); // outputs 6

?>

5. str_replace() function: The str_replace() function replaces some characters with some other characters in a string.

Example:

<?php

echo str_replace("Teak", "Veer", "Cyber Teak!"); // outputs Cyber Veer!

?>

Reference

http://php.net/language.types.string