[R] How to create these variables in R?

[Duncan Murdoch]

On 28/06/2016 7:34 AM, Faradj Koliev wrote:
> Dear all,
>
> Let’s say that I have a dataset that looks something like this:
>
>
> Subject Year    A
>     A   1990    1
>     A   1991    1
>     A   1992    1
>     A   1993    1
>     A   1994    0
>     A   1995    0
>     B   1990    1
>     B   1991    0
>     B   1992    1
>     B   1993    1
>     C   1991    1
>     C   1992    1
>     C   1993    0
>     C   1994    1
>     D   1991    0
>     D   1992    1
>     D   1993    1
>     D   1994    0
>     D   1995    0
>     D   1996    1
>     D   1997    1
>
>
> What I would like to do is to create the following three new variables: A1, A2, and A3
> The variable A1 should capture/count all 1’s in the variable A that are in a row (counting), for each subject-year – but it  should restart counting if there
> are two 0’s in a row (displayed
> below).
>
> The variable A2 should capture 1-2’s (range) in the A1. Displayed in the example below.(subject-year)
>
> The variable A3 should capture all values in the variable A1 that are more than 2, also displayed in the example data below.(subject-year)

A1 has a pretty complicated definition.  There's likely a vectorized way 
to write it, but it won't be easy to read.  I'd just use a loop.  Your 
rules are a little ambiguous (are 0 and 1 the only possible values?) so 
I won't try, but it should be straightforward for you to write the loop.

A2 and A3 are easy:

A2 <- as.numeric(A1 %in% 1:2)
A3 <- as.numeric(A1 > 2)

Duncan Murdoch

>
>
> See the example below for illustration of these variables
>
>
> Subject Year    A   A1  A2  A3
>     A   1990    1   1   1   0
>     A   1991    1   2   1   0
>     A   1992    1   3   0   1
>     A   1993    1   4   0   1
>     A   1994    0   0   0   0
>     A   1995    0   0   0   0
>     B   1990    1   1   1   0
>     B   1991    0   1   1   0
>     B   1992    1   2   1   0
>     B   1993    1   3   0   1
>     C   1991    1   1   1   0
>     C   1992    1   2   1   0
>     C   1993    0   2   1   0
>     C   1994    1   3   0   1
>     D   1991    0   0   0   0
>     D   1992    1   1   1   0
>     D   1993    1   2   1   0
>     D   1994    0   0   0   0
>     D   1995    0   0   0   0
>     D   1996    1   1   1   0
>     D   1997    1   2   1   0
>
>
> I’ve no clue where to start at this stage –I’d appreciate any suggestions and help.
>
>
>
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>
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