How to remove all the variable that named as .x, .y? - r

Question

I have a list of data.frame (lst1). In each data.frame in lst1, we have some variables that looks like test.x, test.y, try.x, try.y. etc.
I want to filter out those variables that were created by merging dataset without filter out those variable first (try, test, etc.). How should I filter them out now?
Thanks.

Answer 1

You can also try this:
#Data
List <- list(A=data.frame(a=1,b=5,test.x=NA,test.y=5),
B=data.frame(a=5,b=6,test.x=NA,try.x=7))
#Remove
myfun <- function(x)
{
i <- which(grepl('.x|.y',names(x)))
x <- x[,-i]
return(x)
}
#Apply
List2 <- lapply(List,myfun)
Output:
List2
$A
a b
1 1 5
$B
a b
1 5 6

Answer 2

Here's a tidyverse approach:
We can use the dplyr::select function to select only the columns we want. matches() allows us to select columns using regular expressions. \\.[xy]$ matches columns that contain a period followed by x or y and $ anchors the match to the end of the string.
The purrr::map function allows us to apply the selection to each list element. ~ defines a formula which is automatically converted to a function.
library(tidyverse)
lst2 <- lst1 %>%
map(~dplyr::select(.,-matches("\\.[xy]$")))
map(lst2, head, 2)
#[[1]]
# ID name
#1 1 A
#2 2 B
#[[2]]
# ID name
#1 1 A
#2 2 B
#[[3]]
# ID name
#1 1 A
#2 2 B
#[[4]]
# ID name
#1 1 A
#2 2 B
#[[5]]
# ID name
#1 1 A
#2 2 B
Sample Data:
lst1 <- replicate(5,data.frame(ID = 1:15, name = LETTERS[1:15], test.x = runif(15), test.y = runif(15)),simplify = FALSE)
map(lst1, head, 2)
#[[1]]
# ID name test.x test.y
#1 1 A 0.03772391 0.2630905
#2 2 B 0.11844048 0.2929392
#[[2]]
# ID name test.x test.y
#1 1 A 0.398029 0.5151159
#2 2 B 0.348489 0.9534869
#[[3]]
# ID name test.x test.y
#1 1 A 0.7447383 0.6862136
#2 2 B 0.3623562 0.7542699
#
#[[4]]
# ID name test.x test.y
#1 1 A 0.9341495 0.8660333
#2 2 B 0.8383039 0.6299427
#[[5]]
# ID name test.x test.y
#1 1 A 0.02662444 0.04502225
#2 2 B 0.29855214 0.46189116

Answer 3

In base R, we can use endsWith
lapply(List, function(x) x[!(endsWith(names(x),
'.x')|endsWith(names(x), '.y'))])
-output
#$A
# a b
#1 1 5
#$B
# a b
#1 5 6
data
List <- list(A = structure(list(a = 1, b = 5, test.x = NA, test.y = 5), class = "data.frame", row.names = c(NA,
-1L)), B = structure(list(a = 5, b = 6, test.x = NA, try.x = 7), class = "data.frame", row.names = c(NA,
-1L)))