LESSON 382 OF 414 · PROJECTS: COMMAND-LINE TOOLS

CLI Tool: wc v2 — Count Words in Scala

Practice

Build a tiny version of the Unix wc -w command. Given a list of lines, return the total number of words (whitespace-separated tokens) across all lines as an integer.

Function signature:

def countWords(lines: List[String]): Int

Example:

Input: lines = ["hello world", "foo bar baz", ""]

Output: 5

The empty string contributes 0 words, "hello world" contributes 2, and "foo bar baz" contributes 3. Total: 5.

Words are separated by one or more spaces or tabs, and leading or trailing whitespace is ignored. A line with no words (empty, or only whitespace) contributes 0, and an empty list of lines gives 0. The input is plain ASCII text.

Iterate over the lines and accumulate the word count. Trim each line first so that an empty or whitespace-only line contributes zero rather than a stray token.

Trim the line, and only when it has content, split it on whitespace with "\s+" and add the length:

val trimmed = line.trim
if (trimmed.nonEmpty) {
    total += trimmed.split("\\s+").length
}

The full solution:

class Solution {
    def countWords(lines: List[String]): Int = {
        var total = 0
        for (line <- lines) {
            val trimmed = line.trim
            if (trimmed.nonEmpty) {
                total += trimmed.split("\\s+").length
            }
        }
        return total
    }
}

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CLI Tool: wc v2 — Count Words in Scala

Wc V2 in Scala