CODEWITHSUNDEEP
rregex
Lathan Liou
Lathan Liou

Reputation: 63

How to remove a cell containing an underscore or a period in R?

I have character strings such as "76.1" and "76.1_0". I'd like to remove all elements of my dataframe that contain either a "." or a "_".

I've tried

df <- df[!grepl("_", "."),]

which didn't work. I know it's my regex that's the issue but I'm not sure how to proceed.

Any help would be appreciated, thank you!

Upvotes: 2

Views: 284

Answers (1)

Julius Vainora
Julius Vainora

Reputation: 48241

Given an example vector

(x <- c("76.1", "76.1_0", "1", "a"))
# [1] "76.1"   "76.1_0" "1"      "a"

one gets the desired result with, e.g.,

(x <- x[!grepl("\\.|_", x)])
# [1] "1" "a"

where I used grepl differently in a couple of aspects

1) The first argument, pattern, has to be a character string ("\\.|_") rather than multiple arguments, as you tried ("_", "."). See ?grepl.

2) As to "combine" two symbols, one needs to use |, which stands for OR.

3) . is a special character and needs to be escaped with \\.

4) You didn't provide the second argument, x; i.e., where the changes should be done.

Upvotes: 2

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