如何计算Ruby数组中的重复元素 [英] How to count duplicate elements in a Ruby array

问题描述

我有一个排序数组:

<预><代码>['FATAL <error title="请求超时.">','FATAL <error title="请求超时.">','FATAL

我想得到这样的东西，但它不一定是散列:

<预><代码>[{:错误=>'FATAL <error title="请求超时.">', :count =>2},{:错误=>'FATAL <error title="系统内存不足，无法运行此查询.">', :count =>1}]

解决方案

以下代码打印您的要求.我会让你决定如何实际使用来生成你正在寻找的哈希:

# 示例数组a=["aa","bb","cc","bb","bb","cc"]# 使散列默认为 0，这样 += 才能正常工作b = Hash.new(0)# 遍历数组，计算重复条目a.每个都做|v|b[v] += 1结尾b. 各做 |k, v|puts "#{k} 出现 #{v} 次"结尾

注意:我刚刚注意到你说数组已经排序.上面的代码不需要排序.使用该属性可能会生成更快的代码.

I have a sorted array:

[
  'FATAL <error title="Request timed out.">',
  'FATAL <error title="Request timed out.">',
  'FATAL <error title="There is insufficient system memory to run this query.">'
]

I would like to get something like this but it does not have to be a hash:

[
  {:error => 'FATAL <error title="Request timed out.">', :count => 2},
  {:error => 'FATAL <error title="There is insufficient system memory to run this query.">', :count => 1}
]

解决方案

The following code prints what you asked for. I'll let you decide on how to actually use to generate the hash you are looking for:

# sample array
a=["aa","bb","cc","bb","bb","cc"]

# make the hash default to 0 so that += will work correctly
b = Hash.new(0)

# iterate over the array, counting duplicate entries
a.each do |v|
  b[v] += 1
end

b.each do |k, v|
  puts "#{k} appears #{v} times"
end

Note: I just noticed you said the array is already sorted. The above code does not require sorting. Using that property may produce faster code.

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