You might want to consider another representation, but it would depend on how you want to use it. Here is a 'list' that records for each row the position of the boys; does this start to give you the type of data that you want? These are the numeric values of where the boys occur.
> x.m b1 b2 b3 b4 b5 b6 [1,] 1 2 1 2 NA NA [2,] 2 2 NA NA NA NA [3,] 1 2 1 1 1 NA [4,] 2 1 NA NA NA NA [5,] 1 NA NA NA NA NA [6,] 2 1 2 1 NA NA > apply(x.m, 1, function(a)which(a == 1)) [[1]] b1 b3 1 3 [[2]] named integer(0) [[3]] b1 b3 b4 b5 1 3 4 5 [[4]] b2 2 [[5]] b1 1 [[6]] b2 b4 2 4 > On 10/25/07, Deepankar Basu <[EMAIL PROTECTED]> wrote: > Hi All, > > I have data on the sequence of births for families with completed > fertility cycle (in a data frame); the relevant variables are called b1, > b2, b3, b4, b5, b6 and record the birth of the first, second, ..., sixth > child. So, > b1=1 if the first birth is male, > b1=2 if the first birth is female, > and b1=NA if the family did not record any first birth. > > Similarly for b2, b3, b4, b5 and b6. > > I want to record the positions of the male children within their > family's birth history. So, I was thinking of creating six variables > boy_1, boy_2, ..., boy_6. boy_1 would record the position of the first > boy, boy_2 would record the position of the second boy and so on till > boy_6. I want to assign a value of zero to boy_i if the family in > question did not have the i_th boy. > > I am not sure how best to do this (i.e., whether to create variables as > I have suggested or do something else) and would appreciate any > suggestions. Later, I want to use the information on the position of the > male births to compute a likelihood function and do an MLE. > > Here is how my data frame would look: > > b1 b2 b3 b4 b5 b6 > 1 2 1 2 NA NA > 2 2 NA NA NA NA > 1 2 1 1 1 NA > 2 1 NA NA NA NA > 1 NA NA NA NA NA > 2 1 2 1 NA NA > > Thanks in advance. > > Deepankar > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.