如何计算Ruby 1.8.5（Sketchup Ruby API）中的重复哈希iten

我需要计算重复，他们需要100%相同，以增加我的计数，但我不能使用Ruby 1.8.5中的nothing，此代码将在google sketchup的插件中运行

GoogleSketchUpRubyAPI 简短答复:

h = Hash.new 0
product_list.each {|p| h[p] += 1}
product_list_result = h.keys.map{|k| k["count"] = h[k]; k}

详细解释这是如何工作的。 从您的数据开始：

product_list = [
                { "product" => 1, "x" => 200, "y" => 100, "z" => 18},
                { "product" => 1, "x" => 200, "y" => 100, "z" => 18},
                { "product" => 1, "x" => 300, "y" => 100, "z" => 18},
                { "product" => 2, "x" => 300, "y" => 100, "z" => 18},
                { "product" => 2, "x" => 100, "y" => 100, "z" => 18},
                { "product" => 2, "x" => 100, "y" => 100, "z" => 18},
                { "product" => 3, "x" => 100, "y" => 100, "z" => 18}
               ];

# First, create a hash to count the number of unique products. Have the initial
# count be 0.
h = Hash.new 0

# Add each product to the hash count.
product_list.each {|p| h[p] += 1}

现在您有了一个散列，其中产品作为键，计数作为值：

h = {{"z"=>18, "y"=>100, "x"=>100, "product"=>3}=>1, {"z"=>18, "y"=>100, "x"=>300, "product"=>1}=>1, {"z"=>18, "y"=>100, "x"=>200, "product"=>1}=>2, {"z"=>18, "y"=>100, "x"=>300, "product"=>2}=>1, {"z"=>18, "y"=>100, "x"=>100, "product"=>2}=>2}

现在将其转换为所需的数组格式：

product_list_result = []
h.keys.each do |k|
    # since each key is a product hash, we can add count to it
    k["count"] = h[k]

    # Now, add that to the array
    product_list_result << k
end

可以更简洁地进行数组转换：

product_list_result = h.keys.map{|k| k["count"] = h[k]; k}

h、 keys从散列h返回一个键数组，散列h只是 你的名单。然后，函数映射用结果替换该数组中的每个对象 后面的块的一个实例，它只是将计数值添加到乘积散列中

product_list.dup.group_by { |h| h }.each_value.map do |value| 
  value.first.tap { |hash| hash['count'] = value.count }
end

=> [{"product"=>1, "x"=>200, "y"=>100, "z"=>18, "count"=>2},
 {"product"=>1, "x"=>300, "y"=>100, "z"=>18, "count"=>1},
 {"product"=>2, "x"=>300, "y"=>100, "z"=>18, "count"=>1},
 {"product"=>2, "x"=>100, "y"=>100, "z"=>18, "count"=>2},
 {"product"=>3, "x"=>100, "y"=>100, "z"=>18, "count"=>1}]

dup

用于不修改原始

产品列表

---

在ruby 1.8.7中测试

在ruby 1.8.5中测试错误：#抱歉，我无法检查RubyUse的较低版本，因为我的

backport

gem在ruby 1.8.5中使用

groupby

product_list_result = h.keys.map{|k| k["count"] = h[k]; k}

product_list.dup.group_by { |h| h }.each_value.map do |value| 
  value.first.tap { |hash| hash['count'] = value.count }
end

=> [{"product"=>1, "x"=>200, "y"=>100, "z"=>18, "count"=>2},
 {"product"=>1, "x"=>300, "y"=>100, "z"=>18, "count"=>1},
 {"product"=>2, "x"=>300, "y"=>100, "z"=>18, "count"=>1},
 {"product"=>2, "x"=>100, "y"=>100, "z"=>18, "count"=>2},
 {"product"=>3, "x"=>100, "y"=>100, "z"=>18, "count"=>1}]