String
Strings
In PHP, a string is a data type used to store text. It is made up of a sequence of characters such as letters, numbers, symbols, and spaces.
A string must always be written inside quotes.
Double or Single Quotes
Single Quotes (' ')
- Treats everything as plain text
- Does not replace variables with values
- Does not interpret special characters like \n, \t
Double Quotes (" ")
- Replaces variables with their values
- Supports special characters like:
- \n → new line
- \t → tab space
String Functions
string functions are built-in functions used to perform operations on text (strings) such as finding length, changing case, replacing words, and more.
1. strlen() – Returns the number of characters in a string.
2. str_word_count() – Counts the number of words in a string.
3. strrev() –Reverses the given string.
4. str_replace() – Replaces a word or character in a string.
5. strtoupper() – Converts string to uppercase.
6. strtolower() – Converts string to lowercase.
Example
// String length: counts total characters
echo strlen("Hello PHP");
echo "
";
// Word count: counts total words
echo str_word_count("Hello PHP Language");
echo "
";
// Reverse string: reverses the text
echo strrev("Hello");
echo "
";
// Replace string: replaces PHP with World
echo str_replace("PHP", "World", "Hello PHP");
echo "
";
// Uppercase: converts all letters to capital
echo strtoupper("hello");
echo "
";
// Lowercase: converts all letters to small
echo strtolower("HELLO");
?>
Concatenate Strings
concatenation means joining two or more strings together to form a single string.
Example
$firstName = "John";
$lastName = "Doe";
echo $firstName . $lastName;
?>