remove columns based on a pattern in their names

Question

I have a data frame like this:

colnames(df) <- c("A",  "B",  "C",  "MO_A",   "MO_B",   "D",   "F",  "MO_D")

Now I wanna remove all the columns that start with "MO_"

What is the best way to do that?

Possible duplicate of [How to drop columns by name pattern in R?](https://stackoverflow.com/questions/15666226/how-to-drop-columns-by-name-pattern-in-r) and [Subset data to contain only columns whose names match a condition](https://stackoverflow.com/questions/18587334/subset-data-to-contain-only-columns-whose-names-match-a-condition) — A. Suliman, Aug 22 '18 at 20:27

score 0 · Answer 1 · answered Aug 22 '18 at 20:28

0

You could do:

for(n in colnames(df)) {
if(grepl("MO_", n)) df[[n]] <- NULL
}

answered Aug 22 '18 at 20:28

SmitM

score 0 · Answer 2 · edited Aug 22 '18 at 20:50

0

Use a regex to get the columns of interest then index the data frame with a negative index to remove them.

With a logical index:

df <- df[, !grepl('MO_', colnames(df))]

With a numeric index:

df <- df[, -grep('MO_', colnames(df))]

edited Aug 22 '18 at 20:50

Rui Barradas

answered Aug 22 '18 at 20:29

jadki

2 Answers2