Strings in php

Jun 20, 2026Trushi Jasani

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A string is a sequence of characters. In php, strings can be written inside single quotes, double quotes, heredoc, or nowdoc syntax.

Creating Strings

<?php
$single = 'Hello World';           // Single quotes
$double = "Hello World";           // Double quotes
$name = "Alice";
$msg = "Hello, $name!";           // Variable interpolation (double only)

echo $msg; // Hello, Alice!
?>

---

String Length

<?php
echo strlen("Hello World"); // 11
?>

---

Heredoc Syntax

Useful for multi-line strings with variable interpolation:

<?php
$name = "Alice";
$text = <<<EOT
Hello, $name!
Welcome to php.
EOT;

echo $text;
?>

Nowdoc Syntax

Like heredoc but no variable interpolation (like single quotes):

<?php
$name = "Alice";
$text = <<<'EOT'
Hello, $name!
This will NOT be interpolated.
EOT;

echo $text; // Hello, $name!
?>

---

String Functions

Case Manipulation

<?php
echo strtolower("HELLO");   // hello
echo strtoupper("hello");   // HELLO
echo ucfirst("hello world"); // Hello world
echo ucwords("hello world"); // Hello World
?>

Trimming

<?php
echo trim("  Hello  ");    // "Hello"
echo ltrim("  Hello  ");   // "Hello  "
echo rtrim("  Hello  ");   // "  Hello"
?>

Searching

<?php
$str = "Hello World";

echo strpos($str, "World");   // 6 (position)
echo strrpos($str, "l");      // 9 (last occurrence)
echo str_contains($str, "World"); // true (php 8+)
echo str_starts_with($str, "Hello"); // true (php 8+)
echo str_ends_with($str, "World");   // true (php 8+)
?>

Replacing

<?php
echo str_replace("World", "php", "Hello World"); // Hello php

// Case-insensitive replace
echo str_ireplace("WORLD", "php", "Hello World"); // Hello php
?>

Substring

<?php
$str = "Hello World";

echo substr($str, 6);      // World
echo substr($str, 0, 5);   // Hello
echo substr($str, -5);     // World
?>

Splitting and Joining

<?php
// Split string into array
$parts = explode(",", "Apple,Banana,Cherry");
print_r($parts); // ["Apple", "Banana", "Cherry"]

// Join array into string
$joined = implode(" - ", $parts);
echo $joined; // Apple - Banana - Cherry
?>

---

String Formatting

<?php
$name = "Alice";
$age = 30;

// sprintf
$msg = sprintf("Name: %s, Age: %d", $name, $age);
echo $msg; // Name: Alice, Age: 30

// number_format
echo number_format(1234567.891, 2); // 1,234,567.89
?>

---

Repeating Strings

<?php
echo str_repeat("Ha", 3); // HaHaHa
?>

---

Reversing Strings

<?php
echo strrev("Hello"); // olleH
?>

---

Padding Strings

<?php
echo str_pad("5", 3, "0", STR_PAD_LEFT);  // 005
echo str_pad("Hi", 10, "-", STR_PAD_BOTH); // ----Hi----
?>

---

Word Count

<?php
echo str_word_count("Hello World php"); // 3
?>

Note: In php, string indexes start at 0. Use $str[0] to access the first character of a string.