将元素和子元素的表格分解为所有可能的排列的大表格

模糊标题的信息，不确定如何描述我正在尝试做什么...该示例将非常清晰，。将元素和子元素的表格分解为所有可能的排列的大表格

require (tibble) 

#I have a (much larger) table of items that I need to turn into a very large lookup table 
ElementMatrix <- tribble(
    ~Category, ~Elements, 
    "Gender", "Male", 
    "Gender", "Female", 
    "Smoking", "Smoker", 
    "Smoking", "Non-Smoker", 
    "Type1", "A", 
    "Type1", "B", 
    "Type1", "C", 
    "Type1", NA 
) 

#into this 
BigLookupMatrix <- tribble(
    ~Gender, ~Smoking, ~Type1, 
    "Male", "Smoker", "A", 
    "Male", "Smoker", "B", 
    "Male", "Smoker", "C", 
    "Male", "Smoker", NA, 
    "Male", "Non-Smoker", "A", 
    "Male", "Non-Smoker", "B", 
    "Male", "Non-Smoker", "C", 
    "Male", "Non-Smoker", NA, 
    "Female", "Smoker", "A", 
    "Female", "Smoker", "B", 
    "Female", "Smoker", "C", 
    "Female", "Smoker", NA, 
    "Female", "Non-Smoker", "A", 
    "Female", "Non-Smoker", "B", 
    "Female", "Non-Smoker", "C", 
    "Female", "Non-Smoker", NA 
) 

#I guessed it would be sonme gather/spready type thing, but that clearly doesnt work 
gather(ElementMatrix, key=Category, value=Elements) #gives me back my origitional matrix 
spread(ElementMatrix, key=Category, value=Elements) #gets angry about Duplicate identifiers

现在，我明显可以做一些嵌套循环，但看起来很杂乱。必须有一个很好和干净的方式来做到这一点。

非常感谢提前的帮助！

来源

2017-08-04 Sylvain

如何用一个小基R与unstack和expand.grid？

expand.grid(unstack(ElementMatrix, Elements ~ Category)) 
    Gender Smoking Type1 
1 Male  Smoker  A 
2 Female  Smoker  A 
3 Male Non-Smoker  A 
4 Female Non-Smoker  A 
5 Male  Smoker  B 
6 Female  Smoker  B 
7 Male Non-Smoker  B 
8 Female Non-Smoker  B 
9 Male  Smoker  C 
10 Female  Smoker  C 
11 Male Non-Smoker  C 
12 Female Non-Smoker  C 
13 Male  Smoker <NA> 
14 Female  Smoker <NA> 
15 Male Non-Smoker <NA> 
16 Female Non-Smoker <NA>

unstack将按照类别划分的元素列，这里返回命名列表。这被提供给expand.grid，它产生具有三元组（Gender-Smoking-Type1）的所有组合的数据帧。

来源

2017-08-04 11:51:04 lmo

哇，谢谢！快速的newby问题：该做什么，该操作员继续使我神秘... – Sylvain

它在许多上下文中使用（主要在模型公式中用于'lm'和'glm'）。你可以在这里把它看作“按类别分组元素”。作为另一个例子，函数'聚合'执行组级聚合。帮助文件（'？aggregate'）中的一个例子显示了可以说“按饲料类型计算鸡的平均体重”的集合（体重〜饲料，数据=鸡，平均值）。 – lmo

一位非常神秘的操作员，但我认为我越来越接近理解它。谢谢！ – Sylvain

你也可以做到这一点tidyverse内：

library(tidyverse) 

ElementMatrix %>% 
    group_by(Category) %>% 
    summarise(Elements = list(Elements)) %>% 
    spread(Category, Elements) %>% 
    as.list() %>% 
    transpose() %>% 
    flatten() %>% 
    expand.grid() %>% 
    arrange(Gender, Smoking, Type1)

来源

2017-08-04 11:56:14 AEF

将元素和子元素的表格分解为所有可能的排列的大表格

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