[R] "For" loop and "if" question
Steven Ranney
steven.ranney at gmail.com
Wed Dec 19 21:42:18 CET 2012
All -
I have a large data frame that looks like
ID p1 p2 p3...p20 Lat1 Lat2 Lat3...Lat20
Long1 Long2 Long3...Long20
1 0 0 1 0 NA NA 29.xx NA
NA NA -89.xx NA
2 1 0 0 1 27.xx NA NA 29.00
-88.00 NA NA -89.xx
3 0 0 0 0 NA NA NA NA
NA NA NA NA
...
[truncated]
where length(ID) = 1300 and the zeroes and ones in the p1-p20 column
correspond to values in the Lat1-Lat20 and Long1-Long20 columns; a 0
indicates no corresponding value and 1 indicates there is a
corresponding value.
I'd like to create a dataframe that is
ID p Lat Long
1 3 29.xx -89.xx
2 1 27.xx -88.xx
2 20 29.xx -89.xx
...
and so on, such that for every ID I have, there is a corresponding row
with each Latn and Longn that may exist.
My problem is that I don't know how to do that in R. I can set up
simple "for" loops, but I don't know how to set up something that has
a "for" and an "if/else" statement. And frankly, with the number of
pX, LatX, and LongX, I think that my if/else statement would be huge
and unwieldly.
Could anyone offer any assistance?
Thanks for your help -
SR
Steven H. Ranney
More information about the R-help
mailing list