Iterating a pipe over objects in a list

I have a series of data frames, and I want to run several functions on them using a pipe. I created a list of the objects as follows (in reality there are around 30 objects):

a <- 1:10
b <- 5:14
c <- 10:19
d <- c(NA, 4:12)
e <- 60:69
f <- 7:16
d1 <- tibble(a, b, c, d, e)
d2 <- tibble(a, b, c, e, f)
d_list <- c(d1, d2)

Then I tried to use a for loop to pipe functions over the data frames:

for(d in d_list){
  d %>% 
    select(c(1, 3:5)) %>% 
    na.omit()
}

If I run the pipeline on one of the tibbles outside of the for loop, it works fine. But inside the loop I get an error: Error in UseMethod("select") :
no applicable method for 'select' applied to an object of class "c('integer', 'numeric')". I guess this means that the parser does not understand that I want to apply the functions to the data frames in d_list; but I don't understand why.

Thanks,

Peter

You need to call list() instead of c(). c() concatenates the two tibbles in a strange way:

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union

a <- 1:10
b <- 5:14
c <- 10:19
d <- c(NA, 4:12)
e <- 60:69
f <- 7:16
d1 <- tibble(a, b, c, d, e)
d2 <- tibble(a, b, c, e, f)
d_list <- c(d1, d2)
d_list
#> $a
#>  [1]  1  2  3  4  5  6  7  8  9 10
#> 
#> $b
#>  [1]  5  6  7  8  9 10 11 12 13 14
#> 
#> $c
#>  [1] 10 11 12 13 14 15 16 17 18 19
#> 
#> $d
#>  [1] NA  4  5  6  7  8  9 10 11 12
#> 
#> $e
#>  [1] 60 61 62 63 64 65 66 67 68 69
#> 
#> $a
#>  [1]  1  2  3  4  5  6  7  8  9 10
#> 
#> $b
#>  [1]  5  6  7  8  9 10 11 12 13 14
#> 
#> $c
#>  [1] 10 11 12 13 14 15 16 17 18 19
#> 
#> $e
#>  [1] 60 61 62 63 64 65 66 67 68 69
#> 
#> $f
#>  [1]  7  8  9 10 11 12 13 14 15 16

If you use list() instead, you can use lapply() on it:

d_list <- list(d1, d2)

d_list <- lapply(d_list, function(x) {
  x %>% 
    select(c(1, 3:5)) %>% 
    na.omit()
})
d_list
#> [[1]]
#> # A tibble: 9 × 4
#>       a     c     d     e
#>   <int> <int> <int> <int>
#> 1     2    11     4    61
#> 2     3    12     5    62
#> 3     4    13     6    63
#> 4     5    14     7    64
#> 5     6    15     8    65
#> 6     7    16     9    66
#> 7     8    17    10    67
#> 8     9    18    11    68
#> 9    10    19    12    69
#> 
#> [[2]]
#> # A tibble: 10 × 4
#>        a     c     e     f
#>    <int> <int> <int> <int>
#>  1     1    10    60     7
#>  2     2    11    61     8
#>  3     3    12    62     9
#>  4     4    13    63    10
#>  5     5    14    64    11
#>  6     6    15    65    12
#>  7     7    16    66    13
#>  8     8    17    67    14
#>  9     9    18    68    15
#> 10    10    19    69    16