Topic: PHP Basics – Part 3 of 10: Control Structures (if, else, elseif, switch, loops)
---
1. Conditional Statements in PHP
PHP allows decision-making in your code through control structures like
---
2. `if`, `else`, and `elseif` Statements
• The condition inside
• You can chain multiple conditions using
---
3. `switch` Statement
• Good for checking a variable against multiple possible values.
• Each
---
4. Loops in PHP
Loops allow repeating code multiple times.
---
5. `while` Loop
• Repeats while the condition is true.
---
6. `do...while` Loop
• Executes at least once even if the condition is false initially.
---
7. `for` Loop
• Most commonly used loop with initializer, condition, and increment.
---
8. `foreach` Loop
• Used to iterate over arrays.
• Also works with key-value pairs:
---
9. Control Keywords
•
•
---
10. Summary
• Conditional logic (
• Loops (
• Control flow is critical for building dynamic applications.
---
Exercise
• Write a PHP script that prints numbers 1 to 20, but skips multiples of 3 using
---
#PHP #ControlStructures #Loops #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
---
1. Conditional Statements in PHP
PHP allows decision-making in your code through control structures like
if, else, elseif, and switch.---
2. `if`, `else`, and `elseif` Statements
<?php
$score = 85;
if ($score >= 90) {
echo "Grade: A";
} elseif ($score >= 80) {
echo "Grade: B";
} elseif ($score >= 70) {
echo "Grade: C";
} else {
echo "Grade: F";
}
?>
• The condition inside
if() must return true or false.• You can chain multiple conditions using
elseif.---
3. `switch` Statement
• Good for checking a variable against multiple possible values.
<?php
$day = "Tuesday";
switch ($day) {
case "Monday":
echo "Start of the week!";
break;
case "Friday":
echo "Weekend is near!";
break;
case "Sunday":
echo "Rest day!";
break;
default:
echo "Just another day.";
}
?>
• Each
case must end with a break to avoid fall-through.---
4. Loops in PHP
Loops allow repeating code multiple times.
---
5. `while` Loop
<?php
$i = 0;
while ($i < 5) {
echo "Number: $i<br>";
$i++;
}
?>
• Repeats while the condition is true.
---
6. `do...while` Loop
<?php
$i = 0;
do {
echo "Count: $i<br>";
$i++;
} while ($i < 3);
?>
• Executes at least once even if the condition is false initially.
---
7. `for` Loop
<?php
for ($i = 1; $i <= 5; $i++) {
echo "Line $i<br>";
}
?>
• Most commonly used loop with initializer, condition, and increment.
---
8. `foreach` Loop
• Used to iterate over arrays.
<?php
$colors = array("red", "green", "blue");
foreach ($colors as $color) {
echo "Color: $color<br>";
}
?>
• Also works with key-value pairs:
<?php
$person = array("name" => "Ali", "age" => 28);
foreach ($person as $key => $value) {
echo "$key: $value<br>";
}
?>
---
9. Control Keywords
•
break – Exit a loop or switch.•
continue – Skip current iteration and go to the next.for ($i = 1; $i <= 5; $i++) {
if ($i == 3) continue;
echo "$i<br>";
}---
10. Summary
• Conditional logic (
if, else, switch) helps make decisions.• Loops (
for, while, foreach) help automate repetitive tasks.• Control flow is critical for building dynamic applications.
---
Exercise
• Write a PHP script that prints numbers 1 to 20, but skips multiples of 3 using
continue, and stops completely if the number is 17 using break.---
#PHP #ControlStructures #Loops #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
❤1🔥1
Topic: PHP Basics – Part 4 of 10: Arrays in PHP (Indexed, Associative, Multidimensional)
---
1. What is an Array in PHP?
• An array is a special variable that can hold multiple values at once.
• In PHP, arrays can be indexed, associative, or multidimensional.
---
2. Indexed Arrays
• Stores values with a numeric index (starting from 0).
• Add elements:
• Count elements:
• Loop through indexed array:
---
3. Associative Arrays
• Uses named keys instead of numeric indexes.
• Loop through associative array:
---
4. Multidimensional Arrays
• Arrays containing one or more arrays.
• Loop through multidimensional array:
---
5. Array Functions You Should Know
•
•
•
•
•
•
•
•
---
6. Summary
• Arrays are powerful tools for storing multiple values.
• Indexed arrays use numeric keys; associative arrays use named keys.
• PHP supports nested arrays for more complex structures.
---
Exercise
• Create a multidimensional array of 3 students with their names and 2 grades.
• Print the average grade of each student using a nested loop.
---
#PHP #Arrays #Multidimensional #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
---
1. What is an Array in PHP?
• An array is a special variable that can hold multiple values at once.
• In PHP, arrays can be indexed, associative, or multidimensional.
---
2. Indexed Arrays
• Stores values with a numeric index (starting from 0).
$fruits = array("apple", "banana", "cherry");
echo $fruits[1]; // Output: banana• Add elements:
$fruits[] = "grape"; // Adds to the end of the array
• Count elements:
echo count($fruits); // Output: 4
• Loop through indexed array:
foreach ($fruits as $fruit) {
echo $fruit . "<br>";
}---
3. Associative Arrays
• Uses named keys instead of numeric indexes.
$person = array(
"name" => "Ali",
"age" => 30,
"city" => "Istanbul"
);
echo $person["name"]; // Output: Ali
• Loop through associative array:
foreach ($person as $key => $value) {
echo "$key: $value<br>";
}---
4. Multidimensional Arrays
• Arrays containing one or more arrays.
$students = array(
array("Ali", 90, 85),
array("Sara", 95, 88),
array("Omar", 78, 82)
);
echo $students[0][0]; // Output: Ali
echo $students[1][2]; // Output: 88
• Loop through multidimensional array:
for ($i = 0; $i < count($students); $i++) {
for ($j = 0; $j < count($students[$i]); $j++) {
echo $students[$i][$j] . " ";
}
echo "<br>";
}---
5. Array Functions You Should Know
•
count() – Number of elements•
array_push() – Add to end•
array_pop() – Remove last element•
array_merge() – Merge arrays•
in_array() – Check if value exists•
array_keys() – Get all keys•
sort(), rsort() – Sort indexed array•
asort(), ksort() – Sort associative array by value/key$colors = array("red", "blue", "green");
sort($colors);
print_r($colors);---
6. Summary
• Arrays are powerful tools for storing multiple values.
• Indexed arrays use numeric keys; associative arrays use named keys.
• PHP supports nested arrays for more complex structures.
---
Exercise
• Create a multidimensional array of 3 students with their names and 2 grades.
• Print the average grade of each student using a nested loop.
---
#PHP #Arrays #Multidimensional #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
❤3
Topic: PHP Basics – Part 8 of 10: Working with Files and Directories
---
1. Introduction to File Handling in PHP
• PHP allows you to create, read, write, append, and delete files on the server.
• You can also manage directories, check if a file exists, and more.
---
2. Opening a File
Use the
•
| Mode | Description |
| ------ | -------------------------------- |
|
|
|
|
|
---
3. Reading from a File
•
• Always use
---
4. Writing to a File
• If the file doesn't exist, it will be created.
• If it exists, it will be overwritten.
---
5. Appending to a File
•
---
6. Reading Line by Line
•
•
---
7. Checking If File Exists
---
8. Deleting a File
---
9. Working with Directories
• Create a directory:
• Check if a directory exists:
• Delete a directory:
---
10. Scanning a Directory
• Returns an array of file and directory names.
---
11. Uploading Files
This is a common use case when working with files in PHP.
HTML Form:
upload.php:
---
12. Summary
• PHP provides powerful tools for file and directory operations.
• You can manage content, upload files, read/write dynamically, and handle directories with ease.
---
Exercise
• Create a PHP script that:
* Checks if a file named
* If it does, reads and prints its contents
* If not, creates the file and writes a welcome message
---
#PHP #FileHandling #Directories #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
---
1. Introduction to File Handling in PHP
• PHP allows you to create, read, write, append, and delete files on the server.
• You can also manage directories, check if a file exists, and more.
---
2. Opening a File
Use the
fopen() function:$handle = fopen("example.txt", "r");•
"r" means read-only. Other modes include:| Mode | Description |
| ------ | -------------------------------- |
|
"r" | Read-only ||
"w" | Write-only (truncates file) ||
"a" | Append ||
"x" | Create & write (fails if exists) ||
"r+" | Read & write |---
3. Reading from a File
$handle = fopen("example.txt", "r");
$content = fread($handle, filesize("example.txt"));
fclose($handle);
echo $content;•
fread() reads the entire file based on its size.• Always use
fclose() to release system resources.---
4. Writing to a File
$handle = fopen("newfile.txt", "w");
fwrite($handle, "Hello from PHP file writing!");
fclose($handle);• If the file doesn't exist, it will be created.
• If it exists, it will be overwritten.
---
5. Appending to a File
$handle = fopen("log.txt", "a");
fwrite($handle, "New log entry\n");
fclose($handle);•
"a" keeps existing content and adds to the end.---
6. Reading Line by Line
$handle = fopen("example.txt", "r");
while (!feof($handle)) {
$line = fgets($handle);
echo $line . "<br>";
}
fclose($handle);•
feof() checks for end of file.•
fgets() reads a single line.---
7. Checking If File Exists
if (file_exists("example.txt")) {
echo "File found!";
} else {
echo "File not found!";
}---
8. Deleting a File
if (file_exists("delete_me.txt")) {
unlink("delete_me.txt");
echo "File deleted.";
}---
9. Working with Directories
• Create a directory:
mkdir("myfolder");• Check if a directory exists:
if (is_dir("myfolder")) {
echo "Directory exists!";
}• Delete a directory:
rmdir("myfolder"); // Only works if empty---
10. Scanning a Directory
$files = scandir("myfolder");
print_r($files);• Returns an array of file and directory names.
---
11. Uploading Files
This is a common use case when working with files in PHP.
HTML Form:
<form action="upload.php" method="post" enctype="multipart/form-data">
<input type="file" name="uploadedFile">
<input type="submit" value="Upload">
</form>
upload.php:
if ($_FILES["uploadedFile"]["error"] === 0) {
$target = "uploads/" . basename($_FILES["uploadedFile"]["name"]);
move_uploaded_file($_FILES["uploadedFile"]["tmp_name"], $target);
echo "Upload successful!";
}---
12. Summary
• PHP provides powerful tools for file and directory operations.
• You can manage content, upload files, read/write dynamically, and handle directories with ease.
---
Exercise
• Create a PHP script that:
* Checks if a file named
data.txt exists* If it does, reads and prints its contents
* If not, creates the file and writes a welcome message
---
#PHP #FileHandling #Directories #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
❤2
Topic: PHP Basics – Part 9 of 10: Sessions, Cookies, and State Management
---
1. Why Use Sessions and Cookies?
• HTTP is stateless – every request is independent.
• To remember users or store temporary data (like login), we use sessions and cookies.
---
### 2. Sessions in PHP
• Sessions store data on the server.
---
Starting a Session
• This creates a unique session ID per user and stores data on the server.
---
Accessing Session Data
---
Destroying a Session
---
Use Cases for Sessions
• Login authentication
• Shopping carts
• Flash messages (e.g., "You’ve logged out")
---
### 3. Cookies in PHP
• Cookies store data on the client’s browser.
---
Setting a Cookie
• Syntax:
---
Accessing Cookie Values
---
Deleting a Cookie
---
Session vs Cookie
| Feature | Session | Cookie |
| ---------- | -------------------------------- | ------------ |
| Storage | Server-side | Client-side |
| Size Limit | Large (server) | \~4KB |
| Expiry | On browser close or set manually | Manually set |
| Security | More secure | Less secure |
---
### 4. Best Practices
• Always use
• Use secure flags (
---
5. Session Timeout Handling
---
6. Flash Messages with Sessions
---
### 7. Summary
• Sessions are best for storing temporary and secure server-side user data.
• Cookies are useful for small, client-side persistent data.
• Use both wisely to build secure and dynamic web applications.
---
Exercise
• Create a login form that stores the username in a session.
• Set a welcome cookie that lasts 1 day after login.
• Display both the session and cookie values after login.
---
#PHP #Sessions #Cookies #Authentication #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023
---
1. Why Use Sessions and Cookies?
• HTTP is stateless – every request is independent.
• To remember users or store temporary data (like login), we use sessions and cookies.
---
### 2. Sessions in PHP
• Sessions store data on the server.
---
Starting a Session
<?php
session_start(); // Always at the top
$_SESSION["username"] = "Ali";
?>
• This creates a unique session ID per user and stores data on the server.
---
Accessing Session Data
<?php
session_start();
echo $_SESSION["username"]; // Output: Ali
?>
---
Destroying a Session
<?php
session_start();
session_unset(); // Remove all session variables
session_destroy(); // Destroy the session
?>
---
Use Cases for Sessions
• Login authentication
• Shopping carts
• Flash messages (e.g., "You’ve logged out")
---
### 3. Cookies in PHP
• Cookies store data on the client’s browser.
---
Setting a Cookie
setcookie("user", "Ali", time() + (86400 * 7)); // 7 days• Syntax:
setcookie(name, value, expiration, path, domain, secure, httponly)---
Accessing Cookie Values
echo $_COOKIE["user"];
---
Deleting a Cookie
setcookie("user", "", time() - 3600); // Expire it in the past---
Session vs Cookie
| Feature | Session | Cookie |
| ---------- | -------------------------------- | ------------ |
| Storage | Server-side | Client-side |
| Size Limit | Large (server) | \~4KB |
| Expiry | On browser close or set manually | Manually set |
| Security | More secure | Less secure |
---
### 4. Best Practices
• Always use
session_start() before outputting anything.• Use secure flags (
secure, httponly) when setting cookies.setcookie("auth", "token", time()+3600, "/", "", true, true);---
5. Session Timeout Handling
session_start();
$timeout = 600; // 10 minutes
if (isset($_SESSION['LAST_ACTIVITY']) && (time() - $_SESSION['LAST_ACTIVITY'] > $timeout)) {
session_unset();
session_destroy();
echo "Session expired.";
}
$_SESSION['LAST_ACTIVITY'] = time();
---
6. Flash Messages with Sessions
// Set message
$_SESSION["message"] = "Login successful!";
// Display then clear
if (isset($_SESSION["message"])) {
echo $_SESSION["message"];
unset($_SESSION["message"]);
}
---
### 7. Summary
• Sessions are best for storing temporary and secure server-side user data.
• Cookies are useful for small, client-side persistent data.
• Use both wisely to build secure and dynamic web applications.
---
Exercise
• Create a login form that stores the username in a session.
• Set a welcome cookie that lasts 1 day after login.
• Display both the session and cookie values after login.
---
#PHP #Sessions #Cookies #Authentication #PHPTutorial #BackendDevelopment
https://t.iss.one/Ebooks2023