Removing the white space at the start of each variable IN A LIST

Question

I'm trying to remove the space that at the start of each variable but not the spaces after that.

I have a list like this:

input= structure(list(X = 2:4, V1 = c(NA, NA, NA), V2 = c(" Tescho123C", 
" Tescho123A", " Tescho123B"), V3 = c(" Instrument", " Instrument", 
" Instrument"), V4 = c(" :Fanta", " :Fanta", " :Fanta"), V5 = c(" :Tool Time", 
" :Tool Time", " :Tool Time")), class = "data.frame", row.names = c(NA, 
-3L))

And I'm trying to get something like this

output = structure(list(X = 2:4, V1 = c(NA, NA, NA), V2 = c("Tescho123C", 
"Tescho123A", "Tescho123B"), V3 = c("Instrument", "Instrument", 
"Instrument"), V4 = c(":Fanta", ":Fanta", ":Fanta"), V5 = c(":Tool Time", 
":Tool Time", ":Tool Time")), class = "data.frame", row.names = c(NA, 
-3L))

Everything I've tried seems to be more complex than it should be and takes a long time to run.

NB: trimws does not work on list - only vectors - and I'd prefer for to have to change my input.

Can anyone suggest an elegant solution?

@Humpelstielzchen that is exactly what I mean. i must be tired, my brain isn't working. if you want to "answer" the question, i'm mark it correct. thanks. — nicshah, Nov 24 '20 at 12:10

score 2 · Accepted Answer · answered Nov 24 '20 at 12:15

2

You can do:

sapply(input, trimws)

Mind however that the result is a matrix, and trimws tunrs everything to character.

answered Nov 24 '20 at 12:15

Humpelstielzchen

6,126
3
14
34

score 1 · Answer 2 · answered Nov 24 '20 at 12:08

Does this work:

library(dplyr)
library(stringr)
input %>% mutate(across(starts_with('V'), ~ str_remove(., '^\\s')))
  X   V1         V2         V3     V4         V5
1 2 <NA> Tescho123C Instrument :Fanta :Tool Time
2 3 <NA> Tescho123A Instrument :Fanta :Tool Time
3 4 <NA> Tescho123B Instrument :Fanta :Tool Time

jayb · Answer 3 · 2020-11-24T12:27:54.490

1

You can use purrr::map and stringr::str_trim, like this:

map(input, ~str_trim(., side = "left"))

EDIT If you want to ignore non-character elements, and so preserve their type, use map_if:

map_if(input, is.character, ~ str_trim(.x, side = "left"))

edited Nov 24 '20 at 12:27

answered Nov 24 '20 at 12:13

jayb

555
3
15

Removing the white space at the start of each variable IN A LIST

3 Answers3