Part II: Single-worker word count
就是自己编写 mapF() 和reduceF().
关键是如何分割出 Word, 这里的定义是:
A word is any contiguous sequence of letters, as determined by unicode.IsLetter.
下面这个分割方式可以通过测试:
tmps := strings.FieldsFunc(contents, func(ch rune) bool {return !unicode.IsLetter(ch)
})可通过测试. 笔者曾按空白分割字符串, 如何检查 string 是否全是 letter 来判断是否是字符, 这样的做法会导致如下:
"it's"// 应该是"it","s""however,"" // "however"等字符串被判断为不是 word.