Topic: PHP Basics – Part 7 of 10: Working with Strings

---

1. Introduction to Strings in PHP

• A string is a sequence of characters used to store and manipulate text.

• Strings can be defined using single quotes (`'`) or double quotes (`"`):

$name = "Ali";
$message = 'Welcome to PHP!';

• Double quotes allow variable interpolation, single quotes do not.

---

2. Concatenating Strings

• Use the dot (.) operator to join strings.

$first = "Hello";
$second = "World";
echo $first . " " . $second; // Output: Hello World

---

3. Common String Functions in PHP

Here are essential functions to manipulate strings:

• strlen($str) – Returns the length of the string.

echo strlen("PHP"); // Output: 3

• strtoupper($str) – Converts all letters to uppercase.

• strtolower($str) – Converts all letters to lowercase.

• ucfirst($str) – Capitalizes the first letter.

• ucwords($str) – Capitalizes first letter of each word.

• strrev($str) – Reverses the string.

---

4. Searching Within Strings

• strpos($str, $search) – Finds the position of first occurrence of a substring.

echo strpos("Hello PHP", "PHP"); // Output: 6

• str_contains($str, $search) – Checks if substring exists (PHP 8+).

---

5. Extracting Substrings

• substr($str, $start, $length) – Extracts part of a string.

$text = "Welcome to PHP";
echo substr($text, 0, 7); // Output: Welcome

---

6. Replacing Text in Strings

• str_replace($search, $replace, $subject) – Replaces all occurrences.

echo str_replace("PHP", "Laravel", "Welcome to PHP"); // Output: Welcome to Laravel

---

7. Trimming and Cleaning Strings

• trim($str) – Removes whitespace from both ends.

• ltrim($str) – From the left side only.

• rtrim($str) – From the right side only.

---

8. String Comparison

• strcmp($str1, $str2) – Returns 0 if both strings are equal.

• strcasecmp($str1, $str2) – Case-insensitive comparison.

---

9. Escaping Characters

• Use backslash (\) to escape quotes:

echo "He said: \"Hello!\"";

---

10. Summary

• Strings are core to user interaction and text processing.

• PHP offers powerful built-in functions to manipulate strings efficiently.

---

Exercise

• Write a function that takes a user's full name and returns:

* The name in all caps
* The reversed name
* The first name only using substr() and strpos()

---

#PHP #Strings #PHPTutorial #StringFunctions #WebDevelopment

https://t.iss.one/Ebooks2023