How to remove row if it has a NA value in one certain column

Question

My data called \"dat\":

A   B   C
NA  2   NA
1   2   3
1   NA  3
1   2   3

I want to be all rows to be removed if it has an NA in column B:

Answer 1

try this:

df<-data.frame(A=c(NA,1,1,1),B=c(2,2,NA,2),C=c(NA,3,3,3))
df<-df[-which(is.na(df$B)),]
df
   A B  C
1 NA 2 NA
2  1 2  3
4  1 2  3