How to loop though entire dataframe in R and get the head function

Question

Assume 3 df:

d1 <- data.frame(replicate(10,sample(0:1,1000,rep=TRUE)))
d2 <- data.frame(replicate(10,sample(0:1,1000,rep=TRUE)))
d3 <- data.frame(replicate(10,sample(0:1,1000,rep=TRUE)))

in R you can view the head of a dataframe with:

head(d1)

Now How can I write function/loop to see the head of all dataframes ?

You should put these data.frames in a list when you create them. — Roland, Oct 12 '21 at 07:05

score 1 · Accepted Answer · answered Oct 12 '21 at 06:49

1

Put the dataframes in a list using mget and use head with lapply -

lapply(mget(paste0('d', 1:3)), head)

answered Oct 12 '21 at 06:49

Ronak Shah

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score 0 · Answer 2 · answered Oct 12 '21 at 07:15

You could also do:

dfs = ls(envir = .GlobalEnv, pattern = "^d")
lapply(dfs, function(x) head(get(x, envir = .GlobalEnv)))

Output:

[[1]]
  X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1  0  1  0  0  1  0  1  1  0   0
2  1  1  0  1  1  1  1  0  0   1
3  1  0  0  0  1  1  1  1  0   0
4  1  0  0  1  1  1  0  0  0   0
5  0  1  1  1  1  1  0  1  0   0
6  0  1  0  0  0  1  1  0  0   0

[[2]]
  X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1  0  1  0  0  1  0  0  0  0   1
2  1  1  1  1  1  0  0  0  0   1
3  1  1  0  0  0  0  1  0  1   0
4  1  0  0  1  0  0  0  1  0   0
5  0  1  1  1  0  0  1  1  1   1
6  1  0  0  1  1  0  0  0  0   0

[[3]]
  X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1  1  1  1  0  1  0  0  1  1   0
2  0  0  1  0  1  1  0  1  1   1
3  0  0  1  0  1  0  0  1  0   0
4  1  0  1  1  1  1  1  0  1   1
5  1  0  0  1  1  0  0  0  0   0
6  0  0  1  1  1  1  0  1  1   0

NOTE: This code assumes that all the variables whose names start with "d" is one of the dataframes that you want to include in the head function.

How to loop though entire dataframe in R and get the head function

2 Answers2