Comparison operators (-eq, -ne, -gt, -lt) in PowerShell - Step-by-Step Execution

Concept Flow - Comparison operators (-eq, -ne, -gt, -lt)

Start

↓

Evaluate Left Value

↓

Evaluate Right Value

↓

Apply Comparison Operator

↓

Result: True or False

↓

Use Result in Script

↓

End

The script compares two values using a comparison operator and produces True or False as the result.

Execution Sample

PowerShell

$a = 5
$b = 3
$a -gt $b
$a -eq $b
$a -ne $b

This code compares two numbers using greater than, equal, and not equal operators.

Execution Table

Step	Expression	Left Value	Right Value	Operator	Result	Explanation
1	$a -gt $b	5	3	-gt	True	5 is greater than 3
2	$a -eq $b	5	3	-eq	False	5 is not equal to 3
3	$a -ne $b	5	3	-ne	True	5 is not equal to 3
4	End					All comparisons done

💡 All comparisons evaluated, script ends.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
$a	5	5	5	5	5
$b	3	3	3	3	3

Key Moments - 2 Insights

Why does $a -gt $b return True but $a -eq $b return False?

Because 5 is greater than 3, so -gt returns True. But 5 is not equal to 3, so -eq returns False. See execution_table rows 1 and 2.

What does -ne operator do?

It checks if two values are not equal. If they differ, it returns True. See execution_table row 3 where 5 -ne 3 is True.

Visual Quiz - 3 Questions

Look at the execution table, what is the result of $a -eq $b at step 2?

A True

B 5

C False

D 3

💡 Hint

Check the 'Result' column in row 2 of the execution_table.

At which step does the comparison check if $a is greater than $b?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Operator' column to find '-gt' in the execution_table.

If $b was changed to 5, what would be the result of $a -eq $b at step 2?

A False

B True

C Error

D Null

💡 Hint

If both values are equal, -eq returns True. Refer to the meaning of -eq in key_moments.

Concept Snapshot

Comparison operators in PowerShell:
-eq : equals (True if values are same)
-ne : not equals (True if values differ)
-gt : greater than (True if left > right)
-lt : less than (True if left < right)
Used to compare values and return True or False.

Full Transcript

This lesson shows how PowerShell compares two values using operators like -eq, -ne, -gt, and -lt. We start by assigning 5 to $a and 3 to $b. Then we check if $a is greater than $b using -gt, which returns True because 5 is greater than 3. Next, we check if $a equals $b with -eq, which returns False because 5 is not equal to 3. Finally, we check if $a is not equal to $b with -ne, which returns True because they differ. These operators help scripts make decisions by comparing values and returning True or False.

Practice

1. Which PowerShell operator checks if two values are equal?

easy

A. -eq

B. -ne

C. -gt

D. -lt

Solution

1. Step 1: Understand the meaning of each operator

   -eq means equals, -ne means not equals, -gt means greater than, -lt means less than.

2. Step 2: Identify the operator for equality

   The operator that checks if two values are equal is -eq.

3. Final Answer:

   -eq -> Option A

4. Quick Check:

   Equals operator = -eq [OK]

Hint: Remember: eq means equal, ne means not equal [OK]

Common Mistakes:

• Confusing -eq with -ne
• Mixing -gt and -lt
• Using == instead of -eq

2. Which of the following is the correct syntax to check if variable $a is greater than 10 in PowerShell?

easy

A. if ($a -gt 10) { }

B. if ($a > 10) { }

C. if ($a -lt 10) { }

D. if ($a -eq 10) { }

Solution

1. Step 1: Recall PowerShell comparison syntax

   PowerShell uses -gt for greater than, not > like some other languages.

2. Step 2: Match the correct operator

   The correct syntax to check if $a is greater than 10 is if ($a -gt 10) { }.

3. Final Answer:

   if ($a -gt 10) { } -> Option A

4. Quick Check:

   Greater than operator = -gt [OK]

Hint: Use -gt for greater than, not > in PowerShell [OK]

Common Mistakes:

• Using > instead of -gt
• Confusing -lt with -gt
• Missing parentheses in if statement

3. What will be the output of this PowerShell code?

$x = 5
if ($x -ne 5) { 'No' } else { 'Yes' }

medium

A. 5

B. No

C. Yes

D. False

Solution

1. Step 1: Evaluate the condition $x -ne 5

   $x is 5, so $x -ne 5 means 5 not equal to 5, which is False.

2. Step 2: Determine which block runs

   Since condition is False, the else block runs, outputting 'Yes'.

3. Final Answer:

   Yes -> Option C

4. Quick Check:

   5 not equal 5 is False, so else runs [OK]

Hint: -ne means not equal; false triggers else block [OK]

Common Mistakes:

• Thinking -ne means equal
• Confusing output with variable value
• Ignoring else block

4. Identify the error in this PowerShell snippet:

$num = 10
if ($num -gt 5) { 'Greater' } elseif ($num -lt 5) { 'Smaller' } else { 'Equal' }

medium

A. Missing closing brace for if block

B. No error, code runs correctly

C. Incorrect use of elseif instead of else if

D. Using -gt instead of > operator

Solution

1. Step 1: Check syntax of if-elseif-else

   PowerShell supports elseif as one word; braces are balanced.

2. Step 2: Verify operators and structure

   -gt and -lt are correct operators; no syntax errors present.

3. Final Answer:

   No error, code runs correctly -> Option B

4. Quick Check:

   elseif is valid in PowerShell [OK]

Hint: PowerShell uses elseif as one word, not else if [OK]

Common Mistakes:

• Thinking elseif is invalid
• Expecting > instead of -gt
• Missing braces confusion

5. You want to write a PowerShell script that prints 'Valid' only if a variable $score is greater than or equal to 70. Which code snippet correctly uses comparison operators to achieve this?

hard

A. if ($score -gt 70) { 'Valid' } else { 'Invalid' }

B. if ($score -lt 70) { 'Valid' } else { 'Invalid' }

C. if ($score -eq 70) { 'Valid' } else { 'Invalid' }

D. if ($score -ge 70) { 'Valid' } else { 'Invalid' }

Solution

1. Step 1: Understand the requirement

   We want to check if $score is greater than or equal to 70.

2. Step 2: Identify the correct operator

   -ge means greater than or equal to, which matches the requirement.

3. Final Answer:

   if ($score -ge 70) { 'Valid' } else { 'Invalid' } -> Option D

4. Quick Check:

   Greater or equal operator = -ge [OK]

Hint: Use -ge for greater or equal comparisons [OK]

Common Mistakes:

• Using -gt excludes 70
• Using -eq only matches exactly 70
• Using -lt reverses logic