Set intersection from a list containing data frames

Question

Set intersection from a list containing data frames

I have a list where each item in the list is a data frame.

> df.list[[1]]
      Change       Diff          VarName
1  10.433354  5.311973e-02         a
2   4.587958  1.517604e-02         b
3   4.566829  1.082679e-02         c
4   4.464458  1.345807e-02         d
5   4.146909  7.758011e-03         e
6   4.141556  1.416043e-02         f

> df.list[[2]]
      Change       Diff          VarName
1  12.443354  5.311973e-02         j
2   3.587958  1.517604e-02         k
3   4.566829  1.082679e-02         a
4   4.464458  1.345807e-02         b
5   3.146909  7.758011e-03         d
6   2.141556  1.416043e-02         e

The length of my list is 10, where there are 10 data frames. each data frame has 30 elements. I want intersect

each top 25 dataframes with a different one and finally get the most common items in all dataframes.

Here's what I've done so far:

df1 <- df.list[[1]]$VarName
df2 <- df.list[[2]]$VarName
df3 <- df.list[[3]]$VarName
df4 <- df.list[[4]]$VarName

intersect(intersect(intersect(df1,df2), df3), df4)

Off to do it using dplyr

any other tool.

+3

r intersection dataframe dplyr

Null-Hypothesis 22 Mar 17 at 22:44

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1 answer

Ruser · Accepted Answer · 2017-03-22T22:57:32+0000

Try Reduce

in R base:

ls <- vector("list", 10)
for (i in 1:10) ls[[i]] <- head(df.list[[i]]$VarName, 25)
Reduce(intersect, ls)

Or a one-line code:

Reduce(intersect, lapply(df.list, function(x) head(x$VarName, 25)))

Set intersection from a list containing data frames

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