How can you use loops and conditional statements in PHP?

1 What are loops in PHP?

Loops are structures that allow you to execute a block of code multiple times until a certain condition is met. Loops are useful for iterating over arrays, processing data, generating output, and more. PHP supports several types of loops, such as for, while, do-while, and foreach. Each loop has a different syntax and behavior, but they all follow the same basic logic: initialize a variable, check a condition, execute the code, and update the variable.

3 How to use for loops in PHP?

A for loop is a loop that executes a block of code for a specified number of times. The syntax of a for loop is:

for (initialization; condition; update) {
  // code to be executed
}        

The initialization is where you declare and assign a variable that will act as a counter. The condition is where you specify the limit or the end point of the loop. The update is where you increment or decrement the counter. The code inside the curly braces is the block of code that will be executed each time the loop runs. For example, you can use a for loop to print the numbers from 1 to 10:

for ($i = 1; $i <= 10; $i++) {
  echo $i . "<br>";
}        

4 How to use while loops in PHP?

A while loop is a loop that executes a block of code as long as a condition is true. The syntax of a while loop is:

while (condition) {
  // code to be executed
}        

The condition is where you specify the condition that will keep the loop running. The code inside the curly braces is the block of code that will be executed each time the loop runs. For example, you can use a while loop to print the numbers from 1 to 10:

$i = 1;
while ($i <= 10) {
  echo $i . "<br>";
  $i++;
}        

5 How to use if statements in PHP?

An if statement is a conditional statement that executes a block of code if a condition is true. The syntax of an if statement is:

if (condition) {
  // code to be executed if condition is true
}        

The condition is where you specify the condition that will trigger the code execution. The code inside the curly braces is the block of code that will be executed if the condition is true. For example, you can use an if statement to check if a user is logged in:

if (isset($_SESSION['user'])) {
  // code to be executed if user is logged in
}        

6 How to use switch statements in PHP?

A switch statement is a conditional statement that executes a block of code based on the value of an expression. The syntax of a switch statement is:

switch (expression) {
  case value1:
    // code to be executed if expression matches value1
    break;
  case value2:
    // code to be executed if expression matches value2
    break;
  ...
  default:
    // code to be executed if expression matches none of the above values
    break;
}        

The expression is where you specify the expression that will be compared with the case values. The case values are where you specify the possible values that the expression can have. The code after each case is the block of code that will be executed if the expression matches that value. The break statement is used to end the execution of the current case and prevent it from falling through to the next case. The default case is where you specify the block of code that will be executed if the expression matches none of the above values. For example, you can use a switch statement to display a message based on the day of the week:

$day = date('w'); // get the numeric representation of the day of the week
switch ($day) {
  case 0:
    echo "It's Sunday!";
    break;
  case 1:
    echo "It's Monday!";
    break;
  case 2:
    echo "It's Tuesday!";
    break;
  case 3:
    echo "It's Wednesday!";
    break;
  case 4:
    echo "It's Thursday!";
    break;
  case 5:
    echo "It's Friday!";
    break;
  case 6:
    echo "It's Saturday!";
    break;
  default:
    echo "Invalid day!";
    break;
}        

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?