単語数比較

wordCount.go

package main

import (
    "code.google.com/p/go-tour/wc"
    "strings"
)

func WordCount(s string) map[string]int {
    var wc map[string]int = make(map[string]int)
    for _, key := range strings.Fields(s) {
        count, hasKey := wc[key]
        if hasKey {
         	wc[key] = count + 1
        } else {
         	wc[key] = 1   
        }
    }
    return wc
}

func main() {
    wc.Test(WordCount)
}

wordCount.hs

wordCount :: String -> [(String, Int)]
wordCount s = foldl count' [] $ words s

count' :: [(String, Int)] -> String -> [(String, Int)]
count' [] w = [(w, 1)]
count' ((v, n):xs) w | v == w    = (v, n+1) : xs
                     | otherwise = (v, n)   : count' xs w