subsetting or filtering out columns that contain letters in a string

[sarah_lee123]

Hello,

I'm looking to create a data frame that excludes columns that contain a certain set of letters in the text.

I do not want to remove the text from the column, but remove the entire column from my new data frame.

P_only_lab_data_HI <- HI_Wide2022 %>% select(contains("MGG"))

This code selects all of the columns that do contain "MGG", but I want the opposite of that for a table that excludes column names containing "MGG"

How do I say something like "Does not contain"?

Thank-you in advance

Sarah

[JackDavison]

Hi Sarah,

You're very very close! Negate your logical expression with ! and you're good to go:

dplyr::select(iris, dplyr::contains("Sepal")) |> names()
#> [1] "Sepal.Length" "Sepal.Width"

dplyr::select(iris, !dplyr::contains("Sepal")) |> names()
#> [1] "Petal.Length" "Petal.Width"  "Species"

^{Created on 2023-02-25 with reprex v2.0.2}

[sarah_lee123]

@JackDavison

dplyr::select(iris, !dplyr::contains("Sepal")) |> names()

Thanks so much for your reply. I'm so new to this that the way you wrote your code and the way I wrote mine are different and the language is still foreign. When I use your way, I end up with one column that contains all of my column names in a vertical fashion. But I want it to return the same Wide version but only return columns with out "MGG"

It tried the following and received error message.
P_only_lab_data_HI <- HI_Wide2022 %>% !select(contains("MGG"))
P_only_lab_data_HI <- HI_Wide2022 %>% select(!contains("MGG"))

It seems like there are so many different ways to get to the same idea it gets confusing to separate everything in my brain.

Thanks again!

~Sarah

[FJCC]

Your second version should screen out columns whose name contains MGG. What error message did you get? Here is a simple example.

library(dplyr)
DF <- data.frame(A = 1:4, MGG = 2:5, A_MGG = 3:6, BFG = 4:7)
DF
#>   A MGG A_MGG BFG
#> 1 1   2     3   4
#> 2 2   3     4   5
#> 3 3   4     5   6
#> 4 4   5     6   7
DFnew <- DF |> select(!contains("MGG"))
DFnew
#>   A BFG
#> 1 1   4
#> 2 2   5
#> 3 3   6
#> 4 4   7

^{Created on 2023-03-02 with reprex v2.0.2}