PHP Strings
Working with text data in PHP
🔤 What are Strings?
Strings are sequences of characters used to store and manipulate text. PHP provides powerful functions to work with strings including concatenation, searching, replacing, and formatting operations.
<?php
$greeting = "Hello World!";
$name = 'Alice';
$message = "Welcome, $name!";
echo $message;
?>
Output:
Welcome, Alice!
String Operations
Concatenation
Join multiple strings together using the dot operator to create longer text from smaller pieces.
<?php
$first = "Hello";
$last = "World";
echo $first . " " . $last;
?>Length
Find the number of characters in a string using strlen() function for validation and processing.
<?php
$text = "Hello";
echo strlen($text); // 5
?>Search
Find specific text within strings using strpos() to locate substrings and their positions.
<?php
$text = "Hello World";
echo strpos($text, "World");
?>Replace
Substitute parts of strings with new text using str_replace() for dynamic content modification.
<?php
$text = "Hello World";
echo str_replace("World", "PHP");
?>🔹 Creating Strings
Different ways to create strings in PHP:
<?php
// Single quotes - literal string
$single = 'Hello World';
// Double quotes - parses variables
$name = "Alice";
$double = "Hello $name";
// Concatenation
$concat = "Hello" . " " . "World";
// Heredoc syntax for multi-line
$heredoc = <<<EOT
This is a
multi-line string
with $name
EOT;
echo $single . "<br>";
echo $double . "<br>";
echo $concat;
?>Output:
Hello World
Hello Alice
Hello World
🔹 String Length and Word Count
Measure string size and count words:
<?php
$text = "Hello World from PHP";
// String length
$length = strlen($text);
echo "Length: $length characters<br>";
// Word count
$words = str_word_count($text);
echo "Words: $words<br>";
// Get all words as array
$wordArray = str_word_count($text, 1);
echo "First word: " . $wordArray[0];
?>Output:
Length: 20 characters
Words: 4
First word: Hello
🔹 String Search and Position
Find text within strings:
<?php
$text = "Hello World! Welcome to PHP World!";
// Find first occurrence
$pos = strpos($text, "World");
echo "First 'World' at position: $pos<br>";
// Find last occurrence
$lastPos = strrpos($text, "World");
echo "Last 'World' at position: $lastPos<br>";
// Check if string contains text
if (strpos($text, "PHP") !== false) {
echo "Text contains 'PHP'";
}
?>Output:
First 'World' at position: 6
Last 'World' at position: 28
Text contains 'PHP'
🔹 String Replace
Replace parts of strings with new text:
<?php
$text = "Hello World!";
// Simple replace
$new = str_replace("World", "PHP", $text);
echo $new . "<br>";
// Replace multiple values
$original = "I like apples and oranges";
$replaced = str_replace(
["apples", "oranges"],
["bananas", "grapes"],
$original
);
echo $replaced . "<br>";
// Case-insensitive replace
$text2 = "Hello WORLD!";
$new2 = str_ireplace("world", "PHP", $text2);
echo $new2;
?>Output:
Hello PHP!
I like bananas and grapes
Hello PHP!
🔹 String Case Conversion
Change string letter casing:
<?php
$text = "Hello World";
// Uppercase
echo strtoupper($text) . "<br>";
// Lowercase
echo strtolower($text) . "<br>";
// First letter uppercase
echo ucfirst("hello world") . "<br>";
// First letter of each word uppercase
echo ucwords("hello world from php");
?>Output:
HELLO WORLD
hello world
Hello world
Hello World From Php
🔹 String Trimming and Splitting
Remove whitespace and split strings:
<?php
// Trim whitespace
$text = " Hello World ";
echo "'" . trim($text) . "'<br>";
// Split string into array
$fruits = "apple,banana,orange";
$array = explode(",", $fruits);
echo "First fruit: " . $array[0] . "<br>";
// Join array into string
$words = ["Hello", "World", "PHP"];
$sentence = implode(" ", $words);
echo $sentence;
?>Output:
'Hello World'
First fruit: apple
Hello World PHP