How to split the dataframes of a list based on a group variable, common in all of them?

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7

I have a list with n dataframes. They have a common variable called group . I want to parse dataframes only with the groups a and c of group .

My goal: Return these dataframes within the list with only these selected rows, based on group .

Following reproducible example ( dput ) for response aid: 

mylist=list(structure(list(number = c(26.1218564352021, 40.3910428239033, 
29.2942556878552, 45.1165094505996, 26.7251219204627, 45.9554967121221, 
47.5653750263155, 43.1406186055392, 47.4260813184083, 23.5751851135865
), group = structure(c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L, 3L
), .Label = c("a", "b", "c"), class = "factor")), class = "data.frame", 
row.names = c(NA, 
-10L)), structure(list(number = c(47.6476960512809, 22.61412369553, 
48.3788266661577, 48.4475369821303, 41.6704738186672, 23.7482307478786, 
28.8278631540015, 30.1230939105153, 27.1230523264967, 49.5825876342133, 
40.2128369128332, 40.5727856047451, 48.3333457401022, 22.921603335999, 
25.0721591082402), group = structure(c(1L, 1L, 1L, 2L, 2L, 2L, 
3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 5L), .Label = c("a", "b", "c", 
"d", "e"), class = "factor")), class = "data.frame", row.names = c(NA, 
-15L)))
    
asked by anonymous 11.09.2018 / 22:01

2 answers

9

You can apply the filter function of the dplyr package inside a lapply 

lapply(mylist, dplyr::filter, group %in% c("a", "c"))

lapply will apply the filter function, with specific arguments: select the groups a and c and return an object of the same type as mylist .

    
11.09.2018 / 22:17
5

Applying subset to multiple criteria: 

lapply(mylist, subset, (group == 'a' | group == 'c') & number > 40)

[[1]]
    number group
2 40.39104     a
7 47.56538     c
8 43.14062     c
9 47.42608     c

[[2]]
    number group
1  47.64770     a
3  48.37883     a
10 49.58259     c
    
11.09.2018 / 23:55
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