PHP if…else…elseif Statements

In PHP, you can use the ‘if’, ‘else’, and ‘elseif’ statements to execute different code blocks based on different conditions.

In PHP, the following conditional statements are available:

1. if – Executes a block of code if a condition is true.
2. if…else – Executes one block of code if a condition is true, and another block of code if the condition is false.
3. if…elseif…else – Allows you to specify multiple conditions and execute different code blocks depending on which condition is true.
4. switch – Allows you to specify multiple conditions and execute different code blocks depending on which condition is true.

Here’s the syntax for an ‘if’ statement:

if (condition) {
  // Code to execute if condition is true
}

Here’s the syntax for an ‘if…else’ statement:

if (condition) {
  // Code to execute if condition is true
} else {
  // Code to execute if condition is false
}

Here’s the syntax for an ‘if…elseif…else’ statement:

if (condition1) {
  // Code to execute if condition1 is true
} elseif (condition2) {
  // Code to execute if condition1 is false and condition2 is true
} else {
  // Code to execute if condition1 and condition2 are false
}

Here’s an example of how you can use an ‘if‘ statement:

$x = 10;

if ($x > 0) {
  echo '$x is positive';
}

Here’s an example of how you can use an ‘if…else’ statement:

$x = 10;

if ($x > 0) {
  echo '$x is positive';
} else {
  echo '$x is not positive';
}

Here’s an example of how you can use an ‘if…elseif…else’ statement:

$x = 10;

if ($x > 0) {
  echo '$x is positive';
} elseif ($x < 0) {
  echo '$x is negative';
} else {
  echo '$x is zero';
}

You can also nest ‘if’ statements within other ‘if’ statements to create more complex conditions.

$x = 10;
$y = 5;

if ($x > 0) {
  if ($y > 0) {
    echo '$x and $y are both positive';
  } else {
    echo '$x is positive and $y is not positive';
  }
} else {
  echo '$x is not positive';
}

Here is an example of how you can use a ‘switch’ statement:

$x = 10;

switch ($x) {
  case 0:
    echo '$x is zero';
    break;
  case 1:
  case 2:
  case 3:
    echo '$x is 1, 2, or 3';
    break;
  default:
    echo '$x is not zero, 1, 2, or 3';
}

The ‘switch’ statement is similar to a series of ‘if…elseif’ statements, but it can be easier to read and write, especially when you have many conditions to test.