[英]Ruby array to hash with dates as keys
我有一個看起來像這樣的數組:
[
["20180630", "14:49", "google", "iOS", "Safari", "1"],
["20180630", "12:22", "google", "Android", "Chrome", "2"],
["20180629", "17:20", "google", "iOS", "Safari", "1"],
["20180629", "16:30", "(direct)", "iOS", "Safari", "1"],
["20180629", "09:29", "(direct)", "Android", "Chrome", "2"]
]
我想要作為輸出的是哈希,其中日期用作鍵:
{
"20180630": [["14:49", "google", "iOS", "Safari", "1"],["12:22", "google", "Android", "Chrome", "2"]],
"20180629": [[...],[...],[...]]
}
Enumerable#group_by
將為您提供數組的哈希轉換,然后只需從結果值中刪除冗余列即可:
hash = input_array.group_by(&:first)
hash.each { |_, list| list.each(&:shift) }
hash
(請注意,這會修改原始數組;如果有問題,您需要將其調整為復制量更大且變異較少的版本)
這是兩種構建所需哈希的方法。 都不會改變給定的數組( arr
)。
arr = [
["20180630", "14:49", "google", "iOS", "Safari", "1"],
["20180630", "12:22", "google", "Android", "Chrome", "2"],
["20180629", "17:20", "google", "iOS", "Safari", "1"],
["20180629", "16:30", "(direct)", "iOS", "Safari", "1"],
["20180629", "09:29", "(direct)", "Android", "Chrome", "2"]
]
arr.each_with_object({}) { |a,h| (h[a.first] ||= []) << a.drop(1) }
#=> {"20180630"=>[["14:49", "google", "iOS", "Safari", "1"],
# ["12:22", "google", "Android", "Chrome", "2"]],
# "20180629"=>[["17:20", "google", "iOS", "Safari", "1"],
# ["16:30", "(direct)", "iOS", "Safari", "1"],
# ["09:29", "(direct)", "Android", "Chrome", "2"]]}
以下是一個變體。
arr.each_with_object(Hash.new { |h,k| h[k] = [] }) { |a,h| h[a.first] << a.drop(1) }
或者,可以使用Hash#update的形式(又名merge!
),該形式采用一個塊來確定要合並的兩個哈希中存在的鍵的值。
arr.each_with_object({}) { |a,h| h.update(a.first=>[a.drop(1)]) { |_,o,n| o+n } }
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