Control flow and looping structures – PowerShell Scripting

PowerShell scripting provides various control flow and looping structures that allow you to control the execution flow and repeat code blocks based on specific conditions. Let’s explore some of the control flow and looping structures available in PowerShell.

If statement:
The if statement allows you to execute a block of code conditionally based on a specified condition. Here’s an example:

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$number = 10

if ($number -gt 0) {
Write-Host “The number is positive.”
}

In this example, the `Write-Host` command will only be executed if the value of `$number` is greater than 0.

If-else statement:
The if-else statement extends the if statement by providing an alternative code block to execute when the condition is false. Here's an example:

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$number = -5

if ($number -gt 0) {
    Write-Host "The number is positive."
}
else {
    Write-Host "The number is non-positive."
}

In this example, the first Write-Host command will be executed if the value of $number is greater than 0. Otherwise, the second Write-Host command will be executed.

Switch statement:
The switch statement allows you to perform different actions based on the value of a variable or expression. It provides a way to handle multiple conditions in a more concise manner. Here’s an example:

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$fruit = “apple”

switch ($fruit) {
“apple” {
Write-Host “It’s an apple.”
}
“banana” {
Write-Host “It’s a banana.”
}
default {
Write-Host “It’s something else.”
}
}

In this example, the `switch` statement checks the value of `$fruit` and executes the corresponding code block based on the matching condition. If no match is found, the `default` code block is executed.

For loop:
The for loop allows you to iterate over a specific range of values or a collection. Here's an example:

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for ($i = 1; $i -le 5; $i++) {
    Write-Host "Iteration $i"
}

This loop will execute the code block inside it five times, printing the iteration number.

Foreach loop:
The foreach loop iterates over each element in a collection. Here’s an example:

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$fruits = “apple”, “banana”, “orange”

foreach ($fruit in $fruits) {
Write-Host “I like $fruit”
}

In this example, the loop iterates over each element in the `$fruits` array and executes the code block, displaying a message for each fruit.

While loop:
The while loop repeatedly executes a code block as long as a specified condition is true. Here's an example:

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$count = 0

while ($count -lt 5) {
    Write-Host "Count: $count"
    $count++
}

PowerShell provides various control flow and looping structures that allow you to control the flow of your script and iterate over collections or perform repetitive tasks. Let’s take a look at some of the commonly used control flow and looping structures in PowerShell scripting:

1. If statement: The if statement allows you to conditionally execute a block of code based on a specified condition. Example:

   $num = 7

   if ($num -gt 5) {
       Write-Host "Number is greater than 5"
   }
   else {
       Write-Host "Number is less than or equal to 5"
   }

2. Switch statement: The switch statement provides a way to perform different actions based on the value of a variable or an expression. Example:

   $fruit = "apple"

   switch ($fruit) {
       "apple" {
           Write-Host "It's an apple"
       }
       "banana" {
           Write-Host "It's a banana"
       }
       default {
           Write-Host "Unknown fruit"
       }
   }

3. For loop: The for loop allows you to iterate over a specific range of values or elements in an array. Example:

   for ($i = 1; $i -le 5; $i++) {
       Write-Host "Iteration $i"
   }

4. Foreach loop: The foreach loop allows you to iterate over each element in a collection, such as an array or a list. Example:

   $fruits = "apple", "banana", "orange"

   foreach ($fruit in $fruits) {
       Write-Host "Current fruit: $fruit"
   }

5. While loop: The while loop allows you to repeat a block of code as long as a condition is true. Example:

   $num = 1

   while ($num -le 5) {
       Write-Host "Current number: $num"
       $num++
   }

These control flow and looping structures provide flexibility and control in your PowerShell scripts. You can use them to handle various scenarios, perform conditional operations, and iterate over collections.

This loop will execute the code block as long as the value of $count is less than 5, incrementing $count in each iteration.
These are some of the control flow and looping structures available in PowerShell scripting. They allow you to customize the execution of your scripts based on conditions and repeat code as needed. By combining these structures, you can create powerful and flexible scripts to automate tasks efficiently.