CODEWITHSUNDEEP
rdataframe
user2087999
user2087999

Reputation: 11

Create and edit a list of dataframes on the fly

I have a list of several strings, and I need to create a list of identical dataframes from it. The strings, for example, are a-d. The list should be

[1] xa
[2] xb
[3] xc
[4] xd

where each element is a dataframe. Each dataframe should have its columns named from another list (the column names are identical across dataframes)

strings <- c("a", "b", "c", "d")
DFList <- list()
for (i in 1:4){
  DFList <- c(DFList,
              assign(paste0("x",strings[i]),
                     data.frame(matrix(0,ncol=5,nrow=0))))
}

doesn't work. It returns 4 dataframes, and a list of 20 elements (4 * 5 columns).

After they're created, I need to then be able to add rows to certain ones of those dataframes later in the script, which I also can't figure out.

How can I go about this?

Upvotes: 0

Views: 138

Answers (1)

Rorschach
Rorschach

Reputation: 32426

You can use replicate or lapply with setNames

setNames(replicate(4, data.frame(matrix(0,4,5)), simplify=FALSE), paste0("x", strings))

The default column names of the data.frames are "X1","X2",etc. So, if you have another list of names for the columns just wrap in another setNames, like setNames(data.frame(...), otherNames).

The lapply syntax is pretty similar,

setNames(lapply(1:4, function(i) data.frame(matrix(0,4,5))), paste0("x", strings))

Upvotes: 1

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