LESSON 378 OF 414 · PROJECTS: COMMAND-LINE TOOLS

CLI Tool: head v2 — First n Lines in Kotlin

Practice

Extend your head command to take an integer n and return the first n lines of lines, joined by newline characters (\n). For this version you may assume 0 ≤ n ≤ lines.size. If n is 0 the result is the empty string.

Function signature:

fun head(lines: List<String>, n: Int): String

Example:

Input: lines = ["alpha", "beta", "gamma", "delta", "epsilon"], n = 3

Output: "alpha\nbeta\ngamma"

When printed:
alpha
beta
gamma

Use lines.subList(0, n) for the first n elements, then joinToString("\n"). Since the problem guarantees n ≤ lines.size, no min needed.

Combine the two calls into one:

return lines.subList(0, n).joinToString("\n")

The full solution:

class Solution {
    fun head(lines: List<String>, n: Int): String {
        return lines.subList(0, n).joinToString("\n")
    }
}

STEP 1 OF 1

Guided

Ctrl + Enter to check

CLI Tool: head v2 — First n Lines in Kotlin

Head V2 in Kotlin