I am working on a project where I need to enter a number of "T score" tables into R. These are tables used to convert raw test scores into standardized values. They generally follow a specific pattern, but not one that is simple. For instance, one pattern is:
34,36,39,42,44,47,50,52,55,58,60,63,66,68,
71,74,76,79,82,84,87,90,92,95,98,100,103,106
I'd prefer to use a simple function to fill these in, rather than typing them by hand. I know that the seq() function can create a simple seqeuence, like:
R> seq(1,10,2)
[1] 1 3 5 7 9
Is there any way to create more complex sequences based on specific patterns? For instance, the above data could be done as:
c(34,seq(36:106,c(3,3,2)) # The pattern goes 36,39,42,44,47,50,52 (+3,+3,+2)
...however, this results in an error. I thought there would be a function that should do this, but all my Google-fu has just brought me back to the original seq().
This could be done using the cumsum (cumulative sum) function and rep:
> 31 + cumsum(rep(c(3, 2, 3), 9))
[1] 34 36 39 42 44 47 50 52 55 58 60 63 66 68 71 74 76 79 82
[20] 84 87 90 92 95 98 100 103
To make sure sure the sequence stops at the right place:
> (31 + cumsum(rep(c(3, 2, 3), 10)))[1:28]
[1] 34 36 39 42 44 47 50 52 55 58 60 63 66 68 71 74 76 79 82
[20] 84 87 90 92 95 98 100 103 106