Re: [R] About Assigning Missing Values

Your assignment of NAs is fine. When you extract, you have to remember to specify whether you want to include or exclude those NA values. Try this: data1.long[data1.long$time==9 & !is.na(data1.long$time), "time"] Jean On Tue, Jan 14, 2014 at 7:22 AM, Chia-Chieh Lin wrote: > Hi all, > >

[R] About Assigning Missing Values

Hi all,   I have a data set, named ‘data1.long’, which has 180 subjects with two variables, ‘time’ and ‘patient’. The ‘time’ variable takes 9 values, i.e., 1, 2, 3,…,9, and the ‘patient’ variable takes two values, 0 and 1. There are 10 subjects for each combination of ‘ti