Multiline strings with trimIndent in Kotlin - Step-by-Step Execution

Concept Flow - Multiline strings with trimIndent

Start multiline string with triple quotes

↓

Write string lines with indentation

↓

Call trimIndent()

↓

Remove common leading whitespace

↓

Return trimmed string

↓

Use or print the string

The flow shows how Kotlin reads a multiline string, removes common indentation with trimIndent(), and returns the cleaned string.

Execution Sample

Kotlin

val text = """
    Hello,
      Kotlin!
""".trimIndent()
println(text)

This code creates a multiline string with indentation, removes common leading spaces using trimIndent(), and prints the cleaned string.

Execution Table

Step	Action	String Content	Indentation Removed	Resulting String
1	Start multiline string	" Hello,\n Kotlin!"	N/A	" Hello,\n Kotlin!"
2	Apply trimIndent()	Same as above	4 spaces (common indent)	"Hello,\n Kotlin!"
3	Print string	N/A	N/A	Hello, Kotlin!

💡 All common leading spaces removed, string printed without extra indentation.

Variable Tracker

Variable	Start	After trimIndent()	Final
text	" Hello,\n Kotlin!"	"Hello,\n Kotlin!"	"Hello,\n Kotlin!"

Key Moments - 2 Insights

Why does trimIndent() remove only 4 spaces and not all spaces from each line?

trimIndent() removes the smallest common indentation from all lines, so it only removes 4 spaces because that is the minimum indentation shared by all lines (see execution_table step 2).

What happens to lines that have more indentation than the common minimum?

Lines with more indentation keep their extra spaces after trimIndent(), preserving relative indentation (see ' Kotlin!' line in execution_table step 2).

Visual Quiz - 3 Questions

Look at the execution_table step 2, how many spaces are removed by trimIndent()?

A All spaces

B 4 spaces

C 2 spaces

D No spaces

💡 Hint

Check the 'Indentation Removed' column in execution_table step 2.

At which step is the string actually printed to the console?

A Step 3

B Step 2

C Step 1

D After all steps

💡 Hint

Look at the 'Action' column for when printing happens in execution_table.

If the first line had no indentation, what would trimIndent() remove?

A 4 spaces from all lines

B All leading spaces from all lines

C No spaces, because common indent is zero

D Only spaces from the first line

💡 Hint

Recall trimIndent() removes the smallest common indent shared by all lines.

Concept Snapshot

Multiline strings use triple quotes """ to include line breaks and spaces.
trimIndent() removes the smallest common leading spaces from all lines.
This keeps relative indentation but cleans up extra spaces.
Use trimIndent() to avoid unwanted indentation in multiline strings.
Print the string to see the cleaned result.

Full Transcript

This example shows how Kotlin handles multiline strings with triple quotes. The string includes lines with indentation. When trimIndent() is called, it finds the smallest number of spaces common to all lines and removes that from each line. This keeps the relative indentation intact but removes extra leading spaces. Finally, printing the string shows the cleaned text without unwanted indentation. This helps keep code readable while formatting strings nicely.