Question

I have a data frame “accdata”.

 dim(accdata)
[1] 6496  188

One of the variables – “VAL” is of interest to me. I must calculate the number of instances where VAL is equal to 24.

I tried a few functions that returned error messages. After some research it seems I need to remove the NA values from VAL first.

I would try something like nonaaccdaa <- na.omit(accdata) except this removes instances of NA in any variable, not just VAL.

I tried nonaval <- na.omit(accdata[accdata$VAL]) but when I then checked the number of rows using nrow the result was null. I had expected a value between 1 and 6,496.

Whats up here?

Answer 1

This should do the trick:

sum(accdata$VAL == 24, na.rm=TRUE)