Change values in row based on a column value r

Question

I am new to R with a fairly simple question, I just can't figure out the answer. For my example I will use a data frame with 3 columns, but my actual data set is 139 columns with 10000 rows.

I want to replace all of the values in a given row with NA if the value in the same row in column C contains a value < 10.

Assume that all of my columns are either number or integer values.

so I want to take the data frame:

x=data.frame(c(5,9,2),c(3,4,6),c(12,9,11))
names(x)=c("A","B","C")

and replace row 2 with NA to create

y=data.frame(c(5,"NA",2),c(3,"NA",6),c(12,"NA",11))
names(y)=c("A","B","C")

Thanks!

Solution

how about:

x[x$C <10 ,] <- NA