Ruby - 为什么+ =会增加我的字符​​串的数量？

Question

在下面的代码从1"seven"变化2值：

word_counts = Hash.new(0) 
sample = "If seven maids with seven mops" 
sample.split.each do |word| 
    word_counts[word.downcase] += 1 
    puts word_counts 
end 

输出：

{} 
{"if"=>1} 
{"if"=>1, "seven"=>1} 
{"if"=>1, "seven"=>1, "maids"=>1} 
{"if"=>1, "seven"=>1, "maids"=>1, "with"=>1} 
{"if"=>1, "seven"=>2, "maids"=>1, "with"=>1} 
{"if"=>1, "seven"=>2, "maids"=>1, "with"=>1, "mops"=>1} 

有人可以解释为什么它从1去2？

Answer 1

OK，我会尝试..

word_counts[word.downcase] += 1意味着word_counts[word.downcase] = word_counts[word.downcase] + 1。现在，在第五次迭代word等于'seven'，所以它确实word_counts['seven'] = word_counts['seven'] + 1。但是word_counts['seven']是1，所以它变成了2。

当你拆分字符串时，你会得到带有两个字符串"seven"的数组，因为该句子有两次出现该单词。

"If seven maids with seven mops".split #=> ["If", "seven", "maids", "with", "seven", "mops"]