Multiline strings with trimIndent in Kotlin - Mini Project: Build & Apply

Multiline strings with trimIndent

📖 Scenario: You are creating a simple Kotlin program to display a formatted message using multiline strings. Multiline strings help keep text readable and maintain the intended layout.

🎯 Goal: Build a Kotlin program that uses a multiline string with trimIndent() to remove extra indentation and print a clean, formatted message.

📋 What You'll Learn

Create a multiline string variable with indented text

Use trimIndent() to remove common leading whitespace

Print the cleaned multiline string

💡 Why This Matters

🌍 Real World

Multiline strings with trimIndent are useful for writing formatted text blocks like messages, SQL queries, or JSON in Kotlin code without extra spaces.

💼 Career

Understanding multiline strings and trimming indentation helps write cleaner, more readable Kotlin code, a skill valuable for Android and backend Kotlin developers.

1

Create a multiline string variable

Create a multiline string variable called message with the following exact content including indentation: """ Hello, Welcome to Kotlin programming! Enjoy learning. """

Kotlin

# Create the multiline string variable 'message' with the given indented text
# Your code here

Hint

Use triple quotes """ to start and end the multiline string.

2

Apply trimIndent() to the multiline string

Add trimIndent() to the message variable to remove the common leading whitespace from each line.

Kotlin

val message = """
    Hello,
    Welcome to Kotlin programming!
    Enjoy learning.
""".trimIndent()
# Your code here

Hint

Call trimIndent() immediately after the multiline string.

3

Print the trimmed multiline string

Write a println statement to print the message variable.

Kotlin

val message = """
    Hello,
    Welcome to Kotlin programming!
    Enjoy learning.
""".trimIndent()

# Print the message variable
# Your code here

Hint

Use println(message) to display the text.

4

Run and verify the output

Run the program and verify that the output matches exactly: Hello, Welcome to Kotlin programming! Enjoy learning.

Kotlin

val message = """
    Hello,
    Welcome to Kotlin programming!
    Enjoy learning.
""".trimIndent()

println(message)
# Run the program and check the output

Hint

The printed text should have no leading spaces on each line.

Practice

1. What does the trimIndent() function do when used with multiline strings in Kotlin?

easy

A. It converts the string to uppercase.

B. It adds extra spaces at the beginning of each line.

C. It splits the string into a list of lines.

D. It removes the common leading whitespace from each line.

Solution

1. Step 1: Understand the purpose of trimIndent()

   The function trimIndent() removes the common leading whitespace from every line in a multiline string.

2. Step 2: Effect on multiline strings

   This makes the string output aligned neatly without extra indentation caused by code formatting.

3. Final Answer:

   It removes the common leading whitespace from each line. -> Option D

4. Quick Check:

   trimIndent() = removes leading spaces [OK]

Hint: trimIndent() cleans leading spaces for neat multiline strings [OK]

Common Mistakes:

• Thinking trimIndent() adds spaces instead of removing
• Confusing trimIndent() with uppercase conversion
• Assuming trimIndent() splits strings into lines

2. Which of the following is the correct syntax to create a multiline string with trimmed indentation in Kotlin?

easy

A. val text = """Hello\nWorld""".trimIndent()

B. val text = "Hello\nWorld".trimIndent()

C. val text = '''Hello\nWorld'''.trimIndent()

D. val text = ""Hello\nWorld"".trimIndent()

Solution

1. Step 1: Identify multiline string syntax

   Kotlin uses triple double quotes """ to create multiline strings.

2. Step 2: Apply trimIndent() correctly

   Calling trimIndent() on the multiline string removes common leading spaces.

3. Final Answer:

   val text = """Hello\nWorld""".trimIndent() -> Option A

4. Quick Check:

   Triple quotes + trimIndent() = correct syntax [OK]

Hint: Use triple quotes """ for multiline strings with trimIndent() [OK]

Common Mistakes:

• Using single quotes instead of triple quotes
• Trying to trimIndent() on a normal string
• Wrong quote count causing syntax errors

3. What will be the output of the following Kotlin code?

val text = """
    Kotlin
    is
    fun
""".trimIndent()
println(text)

medium

A. Kotlin
is
fun

B. Kotlin
is
fun

C. Kotlin
is
fun

D. Kotlin is fun

Solution

1. Step 1: Analyze the multiline string with indentation

   The string has 4 spaces before each line inside the triple quotes.

2. Step 2: Effect of trimIndent()

   trimIndent() removes the common 4-space indentation from all lines.

3. Final Answer:

   Kotlin is fun -> Option C

4. Quick Check:

   trimIndent() removes leading spaces = clean lines [OK]

Hint: trimIndent() removes common leading spaces from all lines [OK]

Common Mistakes:

• Expecting original indentation to remain
• Confusing trimIndent() with trim() which removes only ends
• Thinking output is a single line string

4. Identify the error in this Kotlin code snippet using multiline strings and trimIndent():

val message = """
  Hello
    World
"".trimIndent()
println(message)

medium

A. Missing one double quote in the closing triple quotes.

B. The closing triple quotes should be """ not "".

C. No error; code runs and prints correctly.

D. Incorrect use of trimIndent() on a non-multiline string.

Solution

1. Step 1: Check triple quote syntax

   Multiline strings require triple double quotes """ at start and end.

2. Step 2: Identify the closing quotes

   The code uses only two double quotes "" at the end, which is invalid syntax.

3. Step 3: Correct the closing quotes

   It should be """ to properly close the multiline string.

4. Final Answer:

   The closing triple quotes should be """ not "". -> Option B

5. Quick Check:

   Triple quotes must match at start and end [OK]

Hint: Always close multiline strings with triple quotes """ [OK]

Common Mistakes:

• Using two quotes instead of three to close multiline strings
• Assuming trimIndent() fixes quote errors
• Confusing trimIndent() with trimming quotes

5. You want to create a multiline string in Kotlin that shows a list of fruits without extra indentation in the output. Which code snippet correctly achieves this using trimIndent()?

hard

A. val fruits = """
- Apple
- Banana
- Cherry
""".trimIndent()
println(fruits)

B. val fruits = """
- Apple
- Banana
- Cherry
""".trimIndent()
println(fruits)

C. val fruits = """
- Apple
- Banana
- Cherry
""".trimIndent()
println(fruits)

D. val fruits = "- Apple\n- Banana\n- Cherry".trimIndent()
println(fruits)

Solution

1. Step 1: Understand trimIndent() effect on indentation

   trimIndent() removes the common leading spaces from all lines, aligning text properly.

2. Step 2: Check each option's indentation

   val fruits = """ - Apple - Banana - Cherry """.trimIndent() println(fruits) has consistent 4-space indentation on each line, so trimIndent() will remove it neatly.

3. Step 3: Evaluate other options

   val fruits = """ - Apple - Banana - Cherry """.trimIndent() println(fruits) has uneven indentation, so trimIndent() removes nothing and leaves extra spaces on some lines. val fruits = """ - Apple - Banana - Cherry """.trimIndent() println(fruits) has uneven indentation, so trimIndent() won't align all lines properly. val fruits = "- Apple\n- Banana\n- Cherry".trimIndent() println(fruits) is a normal string, trimIndent() has no effect.

4. Final Answer:

   val fruits = """ - Apple - Banana - Cherry """.trimIndent() println(fruits) -> Option A

5. Quick Check:

   Consistent indentation + trimIndent() = neat output [OK]

Hint: Use consistent indentation inside triple quotes before trimIndent() [OK]

Common Mistakes:

• Using uneven indentation causing partial trimming
• Not using triple quotes for multiline strings
• Expecting trimIndent() to fix uneven spaces