rdataframer-faq

Remove an entire column from a data.frame in R

Does anyone know how to remove an entire column from a data.frame in R? For example if I am given this data.frame:

> head(data)
   chr       genome region
1 chr1 hg19_refGene    CDS
2 chr1 hg19_refGene   exon
3 chr1 hg19_refGene    CDS
4 chr1 hg19_refGene   exon
5 chr1 hg19_refGene    CDS
6 chr1 hg19_refGene   exon

and I want to remove the 2nd column.

Solution

  • You can set it to NULL.

    > Data$genome <- NULL
> head(Data)
   chr region
1 chr1    CDS
2 chr1   exon
3 chr1    CDS
4 chr1   exon
5 chr1    CDS
6 chr1   exon

    As pointed out in the comments, here are some other possibilities:

    Data[2] <- NULL    # Wojciech Sobala
Data[[2]] <- NULL  # same as above
Data <- Data[,-2]  # Ian Fellows
Data <- Data[-2]   # same as above

    You can remove multiple columns via:

    Data[1:2] <- list(NULL)  # Marek
Data[1:2] <- NULL        # does not work!

    Be careful with matrix-subsetting though, as you can end up with a vector:

    Data <- Data[,-(2:3)]             # vector
Data <- Data[,-(2:3),drop=FALSE]  # still a data.frame