From: David Winsemius <dwinsem...@comcast.net>
On Jul 16, 2011, at 12:15 PM, Rory Campbell-Lange wrote:
On 16/07/11, David Winsemius (dwinsem...@comcast.net) wrote:
On Jul 16, 2011, at 11:19 AM, Rory Campbell-Lange wrote:
I'm an R beginner, and I would like to construct a set of boxplots
showing database function runtimes.
I can easily reformat the base data to provide it to R in a format
such as:
function1,12.5
function1,13.11
function1,35.2
...
That is definitely to be preferred. Read that into R and show us the
results of str on your R data object.
Thanks for your suggestion.
str(data2)
'data.frame': 1940170 obs. of 2 variables:
$ function.: Factor w/ 127 levels "fn_activities01_list",..: 102
102 102 102 102 102 102 102 102 102 ...
$ runtime : num 38.1 32.4 41.2 92.9 130.5 ..
head(data2)
function. runtime
1 fn_slot03_byperson 38.083
2 fn_slot03_byperson 32.396
3 fn_slot03_byperson 41.246
4 fn_slot03_byperson 92.904
5 fn_slot03_byperson 130.512
6 fn_slot03_byperson 113.853
tmp <- data2[data2$dbfunc=='fn_slot03_byperson',]
length(tmp$runtime)
[1] 24004
ave(tmp$runtime)[1]
[1] 41.8108
I would have guessed you would get an error, but maybe if ave() is
given no grouping factor it just returns a grand mean.
Try instead one of these:
aggregate(data2, data2$function. , FUN=mean)
tapply(data2$runtime, data2$function. , FUN=mean)
data2$grpmean <- ave( data2$runtime, data2$function. , FUN=mean)
The last one adds a column in the dataframe and could be useful for
identifying items that are some particular diastance away from thier
group mean.
--
David Winsemius, MD
West Hartford, CT
David Winsemius, MD
West Hartford, CT
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