Range operator (..) in PowerShell - Mini Project: Build & Apply

Range operator (..)

📖 Scenario: You are helping a small store owner who wants to list product IDs for a sale. The IDs are numbers in a sequence. You will use PowerShell's range operator to create this list easily.

🎯 Goal: Build a PowerShell script that uses the range operator .. to create a list of product IDs from 101 to 110, then display them.

📋 What You'll Learn

Create a variable called productIDs using the range operator .. to include numbers from 101 to 110

Create a variable called startID and set it to 101

Use the range operator with startID to create productIDs

Print the productIDs variable to show the list of IDs

💡 Why This Matters

🌍 Real World

Range operators help quickly create lists of numbers, useful for IDs, dates, or steps in automation scripts.

💼 Career

Knowing how to generate sequences with range operators is a basic skill for scripting tasks in IT, DevOps, and automation roles.

1

Create the product ID list using the range operator

Create a variable called productIDs and set it to the range of numbers from 101 to 110 using the range operator ...

PowerShell

# Create the productIDs variable with numbers from 101 to 110
# Your code here

Hint

Use .. between two numbers to create a sequence. For example, 1..5 creates numbers 1 to 5.

2

Create a start ID variable

Create a variable called startID and set it to 101.

PowerShell

$productIDs = 101..110
# Create the startID variable and set it to 101
# Your code here

Hint

Just assign the number 101 to the variable startID.

3

Use the startID variable with the range operator

Update the productIDs variable to use the startID variable as the start of the range and 110 as the end of the range.

PowerShell

$productIDs = 101..110
$startID = 101
# Update productIDs to use startID..110
# Your code here

Hint

Use the variable startID on the left side of the .. operator.

4

Display the product IDs

Print the productIDs variable to display the list of product IDs.

PowerShell

$startID = 101
$productIDs = $startID..110
# Print the productIDs variable
# Your code here

Hint

Use Write-Output $productIDs to print the list in PowerShell.

Practice

1. What does the PowerShell range operator 1..5 produce?

easy

A. An empty list

B. A list of numbers from 5 to 1 inclusive

C. A syntax error

D. A list of numbers from 1 to 5 inclusive

Solution

1. Step 1: Understand the range operator syntax

   The range operator .. creates a sequence of numbers from the first number to the second number.

2. Step 2: Apply the operator to 1..5

   It creates a list starting at 1 and ending at 5, including both ends.

3. Final Answer:

   A list of numbers from 1 to 5 inclusive -> Option D

4. Quick Check:

   Range 1..5 = 1,2,3,4,5 [OK]

Hint: Range operator lists numbers from start to end inclusive [OK]

Common Mistakes:

• Thinking it counts down by default
• Expecting exclusive end value
• Confusing syntax with other operators

2. Which of the following is the correct syntax to create a descending range from 5 to 1 in PowerShell?

easy

A. 5-1

B. 1..5

C. 5..1

D. range(5,1)

Solution

1. Step 1: Identify how to create descending ranges

   PowerShell range operator supports descending ranges by placing the higher number first.

2. Step 2: Check the options

   5..1 uses 5..1 which creates a descending list from 5 down to 1.

3. Final Answer:

   5..1 -> Option C

4. Quick Check:

   Descending range = 5..1 [OK]

Hint: Put larger number first for descending range [OK]

Common Mistakes:

• Using 1..5 for descending range
• Using invalid syntax like 5-1
• Using non-PowerShell functions like range()

3. What is the output of this PowerShell command?

1..3 | ForEach-Object { $_ * 2 }

medium

A. 2 4 6

B. 1 2 3

C. 3 6 9

D. Error: Invalid operation

Solution

1. Step 1: Understand the range and pipeline

   The range operator 1..3 produces 1, 2, 3 which are piped one by one.

2. Step 2: Multiply each number by 2

   Each number is multiplied by 2: 1*2=2, 2*2=4, 3*2=6.

3. Final Answer:

   2 4 6 -> Option A

4. Quick Check:

   1..3 * 2 = 2 4 6 [OK]

Hint: Range pipes each number; multiply inside loop [OK]

Common Mistakes:

• Expecting original numbers without multiplication
• Confusing multiplication with addition
• Thinking it produces a syntax error

4. You wrote this code but it throws an error:

5..1..1

What is the problem?

medium

A. Range operator does not support three dots

B. Range operator requires spaces between dots

C. Range operator only works with ascending numbers

D. Range operator needs parentheses around numbers

Solution

1. Step 1: Analyze the syntax used

   The code uses three dots .. twice in a row, making ..1..1 which is invalid.

2. Step 2: Understand range operator limitations

   The range operator only supports two dots .. between two numbers, not three dots or step values.

3. Final Answer:

   Range operator does not support three dots -> Option A

4. Quick Check:

   Only two dots allowed in range operator [OK]

Hint: Range operator uses exactly two dots (..), no more [OK]

Common Mistakes:

• Trying to add step value with extra dots
• Adding spaces between dots
• Assuming parentheses fix syntax

5. You want to create a list of even numbers from 2 to 10 using the range operator and filtering. Which script correctly does this?

hard

A. 2..10 | ForEach-Object { $_ * 2 }

B. 2..10 | Where-Object { $_ % 2 -eq 0 }

C. 1..5 | Where-Object { $_ % 2 -eq 0 }

D. 2..10..2

Solution

1. Step 1: Understand the range and filtering

   The range operator 2..10 creates numbers 2 to 10. Filtering with Where-Object { $_ % 2 -eq 0 } keeps only even numbers.

2. Step 2: Check each option

   2..10 | Where-Object { $_ % 2 -eq 0 } correctly filters evens from 2 to 10. 2..10 | ForEach-Object { $_ * 2 } doubles numbers 2 to 10 (wrong). 1..5 | Where-Object { $_ % 2 -eq 0 } filters evens from 1 to 5 (wrong range). 2..10..2 uses invalid syntax (range operator does not support step).

3. Final Answer:

   2..10 | Where-Object { $_ % 2 -eq 0 } -> Option B

4. Quick Check:

   Filter evens from range with Where-Object [OK]

Hint: Use Where-Object to filter even numbers after range [OK]

Common Mistakes:

• Trying to add step in range operator
• Using wrong range limits
• Multiplying instead of filtering