与nrow频率为R不同的数据帧使用Rep功能

Question

如果我有：

One <- c(rep("X",6),rep("Y",3),rep("Z",2)) 
Two <- c(rep("Blue",4),rep("Red",7)) 

Three <- c(rep("A",4),rep("B",6),rep("C",1)) 
Four <- c(rep("Green",5),rep("Black",6)) 

df1 <- cbind(One,Two) 
df2 <- cbind(Three,Four) 

df.final <- as.data.frame(rbind(df1,df2)) 


Month <- c(rep("January",nrow(df1)), rep("February",nrow(df2))) 
cbind(Month,df.final) 

     Month One Two 
1 January X Blue 
2 January X Blue 
3 January X Blue 
4 January X Blue 
5 January X Red 
6 January X Red 
7 January Y Red 
8 January Y Red 
9 January Y Red 
10 January Z Red 
11 January Z Red 
12 February A Green 
13 February A Green 
14 February A Green 
15 February A Green 
16 February B Green 
17 February B Black 
18 February B Black 
19 February B Black 
20 February B Black 
21 February B Black 
22 February C Black 

一切都是花花公子，但我的问题是Month <- c(rep("January",nrow(df1)), rep("February",nrow(df2)))我将有12个数据帧，并希望大的向量与每个月的频率对应于我拥有的12个数据帧中的每一个的向量。直觉上，我认为像这样的工作：

lapply(c(months*),function(x) rep(x,nrow(c(list of 12 dataframes))##pseudo code 

我试图避免做Months <- c(rep("Jan",nrow(jan.df)),rep("Feb",nrow(feb.df)),...,rep("Dec",nrow(def.df))) 在我要cbind这个矢量的所有月份dataframes的rbind末。就像在这个例子中，除了那里只有两个月。

Answer 1

难道你不只是想从每个数据帧的月表table(df$month)？这会给你一个每月在数据框中出现多少次的计数。

a <- data.frame(rep("january",10)) 
names(a) <- c("Month") 
b <- a 
c <- a 
df_list <- list(a,b,c) 
sapply(df_list,function(x)table(x$Month)) 

!> sapply(df_list,function(x)table(x$Month)) 
january january january 
     10  10  10 

如果你想要的频率，一个月有多少出现在总行，你可以这样做：

sapply(df_list,function(x)table(x$Month)/nrow(x)) 

!> sapply(df_list,function(x)table(x$Month)/nrow(x)) 
january january january 
     1  1  1