Select only numeric variables of a data frame in R [duplicate]

Question

I know that the question is very easy, but I have a more specific one:

I have a data frame, with 50 variables (numeric and non-numeric) and 5000 observations.

Now what I want to do is create another data frame containing only the numerica variables of the original one.

On this website I found the solution of my problem, that is:

numeric_variables<-unlist(lapply(original_data,is.numeric))
X<-original_data[numeric_variables]

But I was wondering: why if I try like this, it does not work instead? what's wrong?

numeric_variables2<-apply(original_data,2,is.numeric)
x<-original_data[numeric_variables2]

apply converts to matrix and matrix can have a single type so, it is essentially converting to character type if there are character columns. Check cbind(1:5, LETTERS[1:5]) with tidyverse, it is original_data %>% select_if(is.numeric) or iris %>% select(where(is.numeric)) — akrun
– akrun, Commented Jun 16, 2020 at 19:15
even better would be iris[mapply(is.numeric, iris)] for example — Daniel O
– Daniel O, Commented Jun 16, 2020 at 19:17
Okay, re-closed, keeping Markus's dupe about how to select numeric column, but also adding a dupe that explains that apply converts things to a matrix, which loses class information. With akrun's comment, hopefully that's enough to steer anyone finding this question in the right direction. — Gregor Thomas
– Gregor Thomas, Commented Jun 16, 2020 at 19:42

Hamza Chennaq · Accepted Answer · 2020-06-16 19:17:44Z

3

names_num <- names(which(sapply(df, is.numeric)))
df_num <- df[, names_num]

answered Jun 16, 2020 at 19:17

Hamza Chennaq

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