Question

我有：

@fruit = ["Apples, Oranges, Bananas", "Apples", "Bananas, Pears", "Bananas, Apples, Pears", "Pears"]

我想用它做两件事，先把它变成一个纯数组，每个只有一个实例：

["Apples", "Oranges", "Bananas", "Pears"]

其次，我希望能够确定数组中给定实例的数量：

@fruit.count("Apples") = 3

第三，是否可以按实例数量对数组进行排序：

@fruit.sort = ["Apples", "Apples", "Apples", "Bananas", "Bananas", "Bananas", "Pears", "Pears", "Pears", "Oranges"]

我必须使用哪些数组/字符串函数来执行此操作？

Answer 1

arr = ["Apples, Oranges, Bananas", "Apples", "Bananas, Pears", "Bananas, Apples, Pears", "Pears"]

hsh = Hash.new { |h, k| h[k] = 0 }

arr.each do |str|
  fruits = str.split(/, /)
  fruits.each do |fruit|
    hsh[fruit] += 1
  end
end

p hsh.keys
# => ["Apples", "Oranges", "Bananas", "Pears"]

hsh.keys.each { |fruit| puts "#{fruit}: #{hsh[fruit]}" }
# => Apples: 3
# => Oranges: 1
# => Bananas: 3
# => Pears: 3

Answer 2

@fruit = ["Apples, Oranges, Bananas", "Apples", "Bananas, Pears", "Bananas, Apples, Pears", "Pears"]

@fruits = @fruit.map{|f| f.split(", ")}.flatten
#=>["Apples", "Oranges", "Bananas", "Apples", "Bananas", "Pears", "Bananas", "Apples", "Pears", "Pears"]
@fruits.uniq
#=> ["Apples", "Oranges", "Bananas", "Pears"]
@fruits.count{|f| f=="Apples"}
#=>3

Answer 3

哈希是更好的数据结构：

@fruit = ["Apples, Oranges, Bananas", "Apples", "Bananas, Pears", "Bananas, Apples, Pears", "Pears"]

h = Hash.new

@fruit.each do |str|
  str.split(/,/).each do |f|
    f.strip!
    h[f] ||= 0
    h[f] += 1
  end
end


h.keys
 => ["Apples", "Oranges", "Bananas", "Pears"] 

h
 => {"Apples"=>3, "Oranges"=>1, "Bananas"=>3, "Pears"=>3} 

h["Apples"]
 => 3

然后，您可以处理哈希中的累积数据，以便在需要时打印出已排序的数组。

Answer 4

@fruit = ["Apples, Oranges, Bananas", "Apples", "Bananas, Pears", "Bananas, Apples, Pears", "Pears"]

p @fruit.map{|f| f.split(', ') }.flatten.uniq
#=> ["Apples", "Oranges", "Bananas", "Pears"]

p @fruit.count{|f| f.include?("Apples")}
#=> 3

在Ruby中操作字符串和数组

4 个答案: