R：将列表与数据帧组合

Question

I have a array of names and a function that returns a data frame. I want to combine this array and data frame. For eg:

>mynames<-c("a", "b", "c")
>df1 <- data.frame(val0=c("d", "e"),val1=4:5)
>df2 <- data.frame(val1=c("e", "f"),val2=5:6)
>df3 <- data.frame(val2=c("f", "g"),val3=6:7)

What I want is a data frame that joins this array with data frame. df1 corresponds to "a", df2 corresponds to "b" and so on. So, the final data frame looks like this:

Names Var    Val
a     d      4
a     e      5
b     e      5
b     f      6
c     f      6
c     g      7

Can someone help me on this?

Thanks.

Answer 1

This answers this particular question, but I'm not sure how much help it will be for your actual problem:

myList <- list(df1, df2, df3)
do.call(rbind, 
        lapply(seq_along(mynames), function(x) 
          cbind(Names = mynames[x], setNames(myList[[x]], 
                                             c("Var", "Val")))))
#   Names Var Val
# 1     a   d   4
# 2     a   e   5
# 3     b   e   5
# 4     b   f   6
# 5     c   f   6
# 6     c   g   7

Here, we create a list of your data.frame s, and in our lapply call, we add in the new "Names" column and rename the existing columns so that we can use rbind to put them all together.