Hello,
I have a data.frame with the following format:
head(clin2)
Study Subject Type Obs Cycle Day Date Time
1 A001101 10108 ALB 44.098 1 2004-03-11 14:26
2 A001101 10108 ALP 95.098 1 2004-03-11 14:26
3 A001101 10108 ALT 61.098 1
Hi:
I did the following test using function ddply() in the plyr package on a toy
data frame with 5 observations using five studies, 20 subjects per
study, 25 cycles per subject, five days per cycle and four observations by
type per day. No date-time variable was included.
# Test data frame
-project.org
Onderwerp: Re: [R] reshape to wide format takes extremely long
Hi:
I did the following test using function ddply() in the plyr
package on a toy data frame with 5 observations using
five studies, 20 subjects per study, 25 cycles per subject,
five days per cycle and four
picking up on Thierry's example, I don't think you need any function because
you are just reshaping
(not aggregating). Therefore:
bigtab2 - cast(data = big, study + subject + cycle + day ~type, value =
obs)
head(bigtab2)
study subject cycle day ALB ALP ALT AST
1 1 1 1 1 66
Hi:
Thanks, David and Thierry. I knew what I did was inefficient, but I'm not
very adept with cast() yet. Thanks for the lesson!
The time is less than half without the fun = mean statement, too. On my
system, the timing of David's call was 2.06 s elapsed; with Thierry's, it
was 4.88 s. Both big
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