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loop function within a loop
4 messages · Sally Zhen, Weidong Gu, David Winsemius +1 more
It's better to avoid loop in this situation. If you want to reorder
subsets of the data based on event, the follow works
df<-read.table('clipboard',header=TRUE)
sp.or<-lapply(split(df,df$group),function(ldf) ldf[order(ldf$event),])
new.df<-do.call('rbind',sp.or)
Weidong Gu
On Wed, Oct 12, 2011 at 10:55 AM, Sally Zhen <saliluna at gmail.com> wrote:
Hi all,
I'm working on a loop function for a large dataset which contains 1000
different groups. I would like to reconstruct the order of events within
each group by using a loop function in R. (Currently the order of events are
based on the ascending order of prev_event within the group)
A demo data frame:
event ? ? ? prev_event ? group
845 ? ? ? ? ?0 ? ? ? ? ? ? ? 5360
926 ? ? ? ? ?153 ? ? ? ? ? ?5360
993 ? ? ? ? ?234 ? ? ? ? ? ?5360
234 ? ? ? ? ?845 ? ? ? ? ? ?5360
848 ? ? ? ? ?926 ? ? ? ? ? ?5360
153 ? ? ? ? ?993 ? ? ? ? ? ?5360
234 ? ? ? ? ?0 ? ? ? ? ? ? ? 8765
968 ? ? ? ? ?234 ? ? ? ? ? ?8765
545 ? ? ? ? ?968 ? ? ? ? ? ?8765
625 ? ? ? ? ?111 ? ? ? ? ? ?3334
744 ? ? ? ? ?181 ? ? ? ? ? ?3334
181 ? ? ? ? ?227 ? ? ? ? ? ?3334
713 ? ? ? ? ?625 ? ? ? ? ? ?3334
227 ? ? ? ? ?713 ? ? ? ? ? ?3334
913 ? ? ? ? ?0 ? ? ? ? ? ? ? 2329
372 ? ? ? ? ?119 ? ? ? ? ? ?2329
719 ? ? ? ? ?189 ? ? ? ? ? ?2329
119 ? ? ? ? ?324 ? ? ? ? ? ?2329
761 ? ? ? ? ?355 ? ? ? ? ? ?2329
890 ? ? ? ? ?372 ? ? ? ? ? ?2329
266 ? ? ? ? ?719 ? ? ? ? ? ?2329
324 ? ? ? ? ?761 ? ? ? ? ? ?2329
189 ? ? ? ? ?890 ? ? ? ? ? ?2329
355 ? ? ? ? ?913 ? ? ? ? ? ?2329
Below is what I have written:
ordering <- vector("list", length(unique(mydata$group)))
for (j in 1:length(unique(mydata$group))){
group.j <- mydata[mydata$group == unique(mydata$group)[j], ]
ordering.j <- c()
ordering.j[1] <- ifelse(group.j[1, ]$prev_event == 0, group.j[1, ]$event,
group.j[1, ]$prev_event)
for (i in 2:nrow(group.j)){
ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$event}
ordering[j] <- ordering.j}
ordering
What I got is:
Error in ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i - ?:
?replacement has length zero
ordering
[[1]] NULL [[2]] NULL [[3]] NULL However, when I accidentally put a typo in the loop function, instead of ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$event}, I put ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$prev_event}, The output is a list of 1000 entries, each with the first event within the group, and I received the following warning messages: [[1]] [1] 1.000680e+17 [[2]] [1] 1.001390e+17 [[3]] [1] 1.001450e+17 49: In ordering[j] <- ordering.j : ?number of items to replace is not a multiple of replacement length 50: In ordering.j[i] <- group.j[group.j$prev_event == ?... : ?number of items to replace is not a multiple of replacement length Why is this happening, and how can I fix it? Any pointer will be greatly appreciated! ? ? ? ?[[alternative HTML version deleted]]
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
On Oct 12, 2011, at 10:55 AM, Sally Zhen wrote:
Hi all, I'm working on a loop function for a large dataset which contains 1000 different groups. I would like to reconstruct the order of events within each group by using a loop function in R.
Not generally a good first strategy in R.
(Currently the order of events are based on the ascending order of prev_event within the group)
Wouldn't this just be: dfrm[order(dfrm$group, dfrm$event), ] (Ascending is the default ordering.)
David.
>
>
> A demo data frame:
>
> event prev_event group
> 845 0 5360
> 926 153 5360
> 993 234 5360
> 234 845 5360
> 848 926 5360
> 153 993 5360
> 234 0 8765
> 968 234 8765
> 545 968 8765
> 625 111 3334
> 744 181 3334
> 181 227 3334
> 713 625 3334
> 227 713 3334
> 913 0 2329
> 372 119 2329
> 719 189 2329
> 119 324 2329
> 761 355 2329
> 890 372 2329
> 266 719 2329
> 324 761 2329
> 189 890 2329
> 355 913 2329
>
>
> Below is what I have written:
>
> ordering <- vector("list", length(unique(mydata$group)))
> for (j in 1:length(unique(mydata$group))){
> group.j <- mydata[mydata$group == unique(mydata$group)[j], ]
> ordering.j <- c()
> ordering.j[1] <- ifelse(group.j[1, ]$prev_event == 0, group.j[1, ]
> $event,
> group.j[1, ]$prev_event)
> for (i in 2:nrow(group.j)){
> ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]
> $event}
> ordering[j] <- ordering.j}
> ordering
>
> What I got is:
> Error in ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i
> - :
> replacement has length zero
>> ordering
> [[1]]
> NULL
>
> [[2]]
> NULL
>
> [[3]]
> NULL
>
>
> However, when I accidentally put a typo in the loop function,
> instead of
> ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]
> $event},
> I put
> ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1],
> ]$prev_event},
> The output is a list of 1000 entries, each with the first event
> within the
> group, and I received the following warning messages:
> [[1]]
> [1] 1.000680e+17
>
> [[2]]
> [1] 1.001390e+17
>
> [[3]]
> [1] 1.001450e+17
>
> 49: In ordering[j] <- ordering.j :
> number of items to replace is not a multiple of replacement length
> 50: In ordering.j[i] <- group.j[group.j$prev_event == ... :
> number of items to replace is not a multiple of replacement length
>
>
> Why is this happening, and how can I fix it? Any pointer will be
> greatly
> appreciated!
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.
David Winsemius, MD
West Hartford, CT
Is this the result you are after, where the event number (within a group) are sorted according to the event/prev_event pairs (prev_event in a row matches event of the previous row)?
ave(d, d$group, FUN=function(z) z[ match(tsort(z$prev_event, z$event)[-1], z$event), ])
event prev_event group
1 845 0 5360
2 234 845 5360
3 993 234 5360
4 153 993 5360
5 926 153 5360
6 848 926 5360
7 234 0 8765
8 968 234 8765
9 545 968 8765
10 625 111 3334
11 713 625 3334
12 227 713 3334
13 181 227 3334
14 744 181 3334
15 913 0 2329
16 355 913 2329
17 761 355 2329
18 324 761 2329
19 119 324 2329
20 372 119 2329
21 890 372 2329
22 189 890 2329
23 719 189 2329
24 266 719 2329
'tsort' is a topological sorting function, like
the Unix tsort. It is overkill for this application
(and probably could be faster and do some more
error checking) but I had it hanging around:
tsort <- function (before, after)
{
# topological sort: Kahn's 1962 algorithm, from Wikipedia
# before and after should be equal-length vectors of the
# same type.
L <- before[0]
S <- setdiff(before, after)
while (length(S) > 0) {
n <- S[1]
S <- S[-1]
L[length(L) + 1] <- n
m <- after[e <- before == n]
after <- after[!e]
before <- before[!e]
S <- c(S, m[!is.element(m, after)])
}
if (length(after) > 0) {
stop("Graph contains a cycle")
}
else {
L
}
}
Your data was
d <- data.frame(
event = c(845, 926, 993, 234, 848, 153, 234, 968, 545, 625, 744, 181,
713, 227, 913, 372, 719, 119, 761, 890, 266, 324, 189, 355),
prev_event = c(0, 153, 234, 845, 926, 993, 0, 234, 968, 111, 181, 227, 625,
713, 0, 119, 189, 324, 355, 372, 719, 761, 890, 913),
group = c(5360, 5360, 5360, 5360, 5360, 5360, 8765, 8765, 8765, 3334,
3334, 3334, 3334, 3334, 2329, 2329, 2329, 2329, 2329, 2329, 2329,
2329, 2329, 2329))
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Sally Zhen
Sent: Wednesday, October 12, 2011 7:56 AM
To: r-help at r-project.org
Subject: [R] loop function within a loop
Hi all,
I'm working on a loop function for a large dataset which contains 1000
different groups. I would like to reconstruct the order of events within
each group by using a loop function in R. (Currently the order of events are
based on the ascending order of prev_event within the group)
A demo data frame:
event prev_event group
845 0 5360
926 153 5360
993 234 5360
234 845 5360
848 926 5360
153 993 5360
234 0 8765
968 234 8765
545 968 8765
625 111 3334
744 181 3334
181 227 3334
713 625 3334
227 713 3334
913 0 2329
372 119 2329
719 189 2329
119 324 2329
761 355 2329
890 372 2329
266 719 2329
324 761 2329
189 890 2329
355 913 2329
Below is what I have written:
ordering <- vector("list", length(unique(mydata$group)))
for (j in 1:length(unique(mydata$group))){
group.j <- mydata[mydata$group == unique(mydata$group)[j], ]
ordering.j <- c()
ordering.j[1] <- ifelse(group.j[1, ]$prev_event == 0, group.j[1, ]$event,
group.j[1, ]$prev_event)
for (i in 2:nrow(group.j)){
ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$event}
ordering[j] <- ordering.j}
ordering
What I got is:
Error in ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i - :
replacement has length zero
ordering
[[1]] NULL [[2]] NULL [[3]] NULL However, when I accidentally put a typo in the loop function, instead of ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$event}, I put ordering.j[i] <- group.j[group.j$prev_event == ordering.j[i-1], ]$prev_event}, The output is a list of 1000 entries, each with the first event within the group, and I received the following warning messages: [[1]] [1] 1.000680e+17 [[2]] [1] 1.001390e+17 [[3]] [1] 1.001450e+17 49: In ordering[j] <- ordering.j : number of items to replace is not a multiple of replacement length 50: In ordering.j[i] <- group.j[group.j$prev_event == ... : number of items to replace is not a multiple of replacement length Why is this happening, and how can I fix it? Any pointer will be greatly appreciated! [[alternative HTML version deleted]]
______________________________________________ R-help at 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.