beginner programming question

Another way to approach this is to first massage the data into a more
regular format.  This may or may not be simpler or faster than other
solutions suggested.

 > x <- read.table("clipboard", header=T)
 > x

   rel1 rel2 rel3 age0 age1 age2 age3 sex0 sex1 sex2 sex3
1    1    3   NA   25   23    2   NA    1    2    1   NA
2    4    1    3   35   67   34   10    2    2    1    2
3    1    4    4   39   40   59   60    1    2    2    1
4    4   NA   NA   45   70   NA   NA    2    2   NA   NA

 > nn <- c("rel","age0","age","sex0","sex")
 > xx <- rbind("colnames<-"(x[,c("rel1","age0","age1","sex0","sex1")], nn),

+  "colnames<-"(x[,c("rel2","age0","age2","sex0","sex2")], nn),
+  "colnames<-"(x[,c("rel3","age0","age3","sex0","sex3")], nn))

 > xx

    rel age0 age sex0 sex
1    1   25  23    1   2
2    4   35  67    2   2
3    1   39  40    1   2
4    4   45  70    2   2
11   3   25   2    1   1
21   1   35  34    2   1
31   4   39  59    1   2
41  NA   45  NA    2  NA
12  NA   25  NA    1  NA
22   3   35  10    2   2
32   4   39  60    1   1
42  NA   45  NA    2  NA

 >
 > rbind(subset(xx, xx$rel==1 & (xx$sex0==1 |

xx$sex0==xx$sex))[,c("age0","age")], subset(xx, xx$rel==1 & xx$sex==1 &
xx$sex0!=xx$sex)[,c("age","age0")])
    age0 age
1    25  23
3    39  40
21   35  34

 >

hope this helps,

Tony Plate

PS.  To advanced R users: Is the above usage of the "colnames<-" function
within an expression regarded as acceptable or as undesirable programming
style? -- I've rarely seen it used, but it can be quite useful.

At Wednesday 09:28 PM 12/17/2003 +0200, Adrian Dusa wrote:

Hi all,



The last e-mails about beginners gave me the courage to post a question;
from a beginner's perspective, there are a lot of questions that I'm
tempted to ask. But I'm trying to find the answers either in the
documentation, either in the about 15 free books I have, either in the
help archives (I often found many similar questions posted in the past).

Being an (still actual) user of SPSS, I'd like to be able to do
everything in R. I've learned that the best way of doing it is to
struggle and find a solution no matter what, refraining from doing it
with SPSS. I've became more and more aware of the almost unlimited
possibilities that R offers and I'd like to completely switch to R
whenever I think I'm ready.



I have a (rather theoretical) programming problem for which I have found
a solution, but I feel it is a rather poor one. I wonder if there's some
other (more clever) solution, using (maybe?) vectorization or
subscripting.



A toy example would be:



rel1       rel2       rel3       age0     age1     age2     age3
sex0     sex1     sex2     sex3

1          3          NA        25         23         2          NA
1          2          1          NA

4          1          3          35         67         34         10
2          2          1          2

1          4          4          39         40         59         60
1          2          2          1

4          NA        NA        45         70         NA        NA
2          2          NA        NA



where rel1...3 states the kinship with the respondent (person 0)

code 1 meaning husband/wife, code 4 meaning parent and code 3 for
children.



I would like to get the age for husbands (code 1) in a first column and
wife's age in the second:



ageh     agew

25         23

34         35

39         40



My solution uses *for* loops and *if*s checking for code 1 in each
element in the first 3 columns, then checking in the last three columns
for husband's code, then taking the corresponding age in a new matrix.
I've learned that *for* loops are very slow (and indeed with my dataset
of some 2000 rows and 13 columns for kinship it takes quite a lot).

I found the "Looping" chapter in "S poetry" very useful (it did saved me
from *for* loops a couple of times, thanks!).



Any hints would be appreciated,

Adrian



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Adrian Dusa (adi at roda.ro)
Romanian Social Data Archive (www.roda.ro <http://www.roda.ro/> )
1, Schitu Magureanu Bd.
76625 Bucharest sector 5
Romania


Tel./Fax:

+40 (21) 312.66.18\

+40 (21) 312.02.10/ int.101




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