在R中-如何删除data.frame中的特定列？

Question

In this data.frame:

I want to remove some columns that "Total" == 0

I reviewed some questions about my problems in here and I found it

R: how to remove certain rows in data.frame

but I can't apply perfectly in my case.

Answer 1

Assuming that the "Total" in the "x' column denotes the last row (I have no reason to think otherwise), we subset the last row ( nrow(df1) ) and remove the first column (as it is non-numeric), check whether that is not equal to 0. We get a logical vector from that. Concatenate ( c ) with TRUE so that we can also get the first column ie "x" in the subset dataset.

df1[c(TRUE,df1[nrow(df1),-1]!=0)]
#      x v2 v3
#1     a  1  0
#2     b  3  1
#3 Total  4  1

data

df1 <- data.frame(x= c('a', 'b', 'Total'),
     v1= c(0,0,0), v2= c(1,3,4), v3=c(0, 1,1))