R中列表的出现次数

Question

我列出了大约100,000次出现的项目被排列在一起，我已粘贴到一列中，因此我可以统计每个组合出现的次数。

4845 Curly Fries California Burger 1 
4846 French Fries California Burger 1 
4847 Hamburger California Burger  1 
4848 $1 Fountain Drinks Curly Fries 1 
4849 $1 Fountain Drinks Curly Fries 1 
4850 California Burger Curly Fries 1 
4851 Curly Fries Curly Fries   1 

我已经探索了聚合函数使我有以下错误：

aggregate(t1$count,list(t1$pc), sum) <br> 
Error in sort.list(y) : 'x' must be atomic for 'sort.list' 
Have you called 'sort' on a list? <br> 

我也曾尝试ddply的变化：

ddply(t1,t1$pc,transform,occurances=sum(t1$count)) 

但我得到这个错误

Error in UseMethod("as.quoted") : 
no applicable method for 'as.quoted' applied to an object of class "c('matrix', 'list')" 

我假设我得到这个，因为我试图通过一个字符值本质上“组”。我也根据对类似问题的回答探讨了tapply和recast，但无济于事。

我怎样才能得到这个组合数？

的考虑，单独列出的项目（再次，道歉的格式问题）的一个样本：

    Var1      Var2 Var3 
>2    Onion Rings    Onion Rings 1 
>3 Pineapple Cheddar Burger    Onion Rings 1 
>4    Onion Rings Pineapple Cheddar Burger 1 
>5 Pineapple Cheddar Burger Pineapple Cheddar Burger 1 
>5    Onion Rings    Onion Rings  1 
>6 Pineapple Cheddar Burger    Onion Rings 1 
>7    Onion Rings Pineapple Cheddar Burger 1 
>8 Pineapple Cheddar Burger Pineapple Cheddar Burger 1 
>9    Fountain Soda   Fountain Soda 1 
>10    French Fries   Fountain Soda 1 

Answer 1

您的初始方法与我想要的非常接近。将这些组合成一个单一的因素肯定会奏效，只要你按照相同的顺序将它们结合起来，这样你就不会以“薯条，汉堡”和“汉堡，薯条”结束。

可能有更简单的方法来做你想做的事，但我没有脑子是什么。尽管如此，我认为这是你要找的东西：

# Let's assume your data looks like this: 
> df 
         Var1      Var2 Var3 
1    Onion Rings    Onion Rings 1 
2 Pineapple Cheddar Burger    Onion Rings 1 
3    Onion Rings Pineapple Cheddar Burger 1 
4 Pineapple Cheddar Burger Pineapple Cheddar Burger 1 
5    Onion Rings    Onion Rings 1 
6 Pineapple Cheddar Burger    Onion Rings 1 
7    Onion Rings Pineapple Cheddar Burger 1 
8 Pineapple Cheddar Burger Pineapple Cheddar Burger 1 
9    Fountain Soda    Fountain Soda 1 
10    French Fries    Fountain Soda 1 

# Now, for each row 
#  1. sort the Var1 and Var2, 
#  2. combine the sorted vars, and 
#  3. convert them back into a factor 

df$sortcomb <- as.factor(apply(df[,1:2], 1, function(x) paste(sort(x), collapse=", "))) 

table(df$sortcomb) # then use table as per normal 

ddply(df, .(sortcomb), summarize, count=length(sortcomb)) # or ddply 

Answer 2

的table()功能是在这里帮助：

with(t1, table(pc)) ## or equivalently table(t1$pc) 

这是假定pc是因子变量，你想要统计出现次数。 （如果它不是一个因素，它会被强制为一个。）