How can I remove columns from a dataframe without being as follows?
> df
x y z
1 1 6 A
2 1 5 B
3 2 4 C
4 2 3 D
5 3 2 E
6 3 1 F
> df <- data.frame(df[,1:2])
> df
x y
1 1 6
2 1 5
3 2 4
4 2 3
5 3 2
6 3 1
R: Remove columns from a dataframe [duplicate]
1
asked by anonymous 22.12.2015 / 17:50
3 answers
2
The most practical form is as follows: df$z <- NULL .
22.12.2015 / 17:52
5
You can do this too:
df[, -3]
Negative indices exclude columns in R .
If you want to delete more than one column, do so:
df[,-c(1,3)]
The problem in this way is that if only one column remains, it is automatically transformed into a vector. If you do not want this behavior use the drop = F argument.
df[,-c(1,3), drop = F]
Another way is to use the dplyr package and the select function:
df %>% select(-z)
Or
df %>% select(-3)
You often want to delete a column without knowing its name beforehand. For example, its name is saved in a variable.
In this case you can do this:
nome_col <- "z"
df[[nome_col]] <- NULL
If you want to delete multiple columns in this way, you can do this:
nomes_col <- c("z", "x")
df[ , -which(names(df) %in% nomes_col), drop = F]
In this case, I use the argument drop = F so that data.frame does not turn vector.
22.12.2015 / 18:28
1
There is yet another, slightly more obscure form:
df[setdiff(names(df), "z")]
22.12.2015 / 18:38