Jessica Streicher
2012-Dec-20 12:46 UTC
[R] Filling Lists or Arrays of variable dimensions
Following problem:
Say you have a bunch of parameters and want to produce results for all
combinations of those:
height<-c("high","low")
width<-c("slim","wide")
then what i used to do was something like this:
l<-list()
for(h in height){
l[[h]]<-list()
for(w in width){
l[[h]][[w]] <- doSomething()
}
}
Now those parameters aren't always the same. Their number can change and the
number of entries can change, and i'd like to have one code that can handle
all configurations.
Now i thought i could use expand.grid() to get all configurations ,and than
iterate over the rows, but the problem then is that i cannot set the values in
the list like above.
grid<-expand.grid(height,width)
l[[as.character(grid[1,])]] <-1
Error in `[[<-`(`*tmp*`, as.character(grid[1, ]), value = 1) :
no such index at level 1
This will only work if the "path" for that is already existent, and
i'm not sure how to build that in this scenario.
I then went on and built an array instead lists of lists, but that doesn't
help either because i can't access the array with what i have in the grids
row - or at least i don't know how.
Any ideas?
I'd prefer to keep the named lists since all other code is built towards
this.
Dear Jessica
Aggregate is a function that allows you to perform loops across multiple
variables.
tempData <- data.frame(height = rnorm(20, 100, 10),
width = rnorm(20, 50, 5),
par1 = rnorm(20))
tempData$htfac <- cut(tempData$height, c(0, 100, 200))
tempData$wdfac <- cut(tempData$width, c(0, 50, 100))
doSomething <- function(x) { mean(x) }
out <- aggregate(tempData["par1"], tempData[c("htfac",
"wdfac")], doSomething)
# out is a data frame; this is a named list.
# use as.list to remove the data.frame class
> as.list(out)
$htfac
[1] (0,100] (100,200] (0,100] (100,200]
Levels: (0,100] (100,200]
$wdfac
[1] (0,50] (0,50] (50,100] (50,100]
Levels: (0,50] (50,100]
$par1
[1] -1.0449563 -0.3782483 -0.9319105 0.8837459
I believe you are seeing an error similar to this one:
> out[[1:3]] <- 1
Error in `[[<-`(`*tmp*`, i, value = value) :
recursive indexing failed at level 2
This is because double square brackets for lists can only set a single list
element at once; grid[1, ] is longer.
Happy Christmas
Chris
Chris Campbell
Tel. +44 (0) 1249 705 450?| Mobile. +44 (0) 7929 628 349
mailto:ccampbell at mango-solutions.com?| http://www.mango-solutions.com
Mango Solutions
2 Methuen Park
Chippenham
Wiltshire
SN14 OGB
UK
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Jessica Streicher
Sent: 20 December 2012 12:46
To: R help
Subject: [R] Filling Lists or Arrays of variable dimensions
Following problem:
Say you have a bunch of parameters and want to produce results for all
combinations of those:
height<-c("high","low")
width<-c("slim","wide")
then what i used to do was something like this:
l<-list()
for(h in height){
l[[h]]<-list()
for(w in width){
l[[h]][[w]] <- doSomething()
}
}
Now those parameters aren't always the same. Their number can change and the
number of entries can change, and i'd like to have one code that can handle
all configurations.
Now i thought i could use expand.grid() to get all configurations ,and than
iterate over the rows, but the problem then is that i cannot set the values in
the list like above.
grid<-expand.grid(height,width)
l[[as.character(grid[1,])]] <-1
Error in `[[<-`(`*tmp*`, as.character(grid[1, ]), value = 1) :
no such index at level 1
This will only work if the "path" for that is already existent, and
i'm not sure how to build that in this scenario.
I then went on and built an array instead lists of lists, but that doesn't
help either because i can't access the array with what i have in the grids
row - or at least i don't know how.
Any ideas?
I'd prefer to keep the named lists since all other code is built towards
this.
______________________________________________
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.
--
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Jessica,
In terms of initializing your list for populating it in a later step, I think
this partially gets at your question -- it removes the upper loop assignment,
but then does require a loop to get the second level. Perhaps there's
something here you can work with ...
height<-c("high","low")
width<-c("slim","wide")
l <- vector("list",length(height))
names(l) <- height
for(i in 1:length(l)){
l[[i]] <- vector("list",length(width))
names(l[[i]]) <- width
}
Best
Tim
Date: Fri, 21 Dec 2012 11:34:06 +0100
From: Jessica Streicher <j.streicher at micromata.de>
To: David Winsemius <dwinsemius at comcast.net>
Cc: R help <r-help at r-project.org>
Subject: Re: [R] Filling Lists or Arrays of variable dimensions
Message-ID: <BE0EF9BE-A571-45F3-92E6-72E093BB50CA at micromata.de>
Content-Type: text/plain; charset=us-ascii
@David : In my mind it was quite complete enough.
@William: Thanks, didn't know you could do that with data frames, if i ever
have to do something similar again i might try this.
On 20.12.2012, at 22:39, David Winsemius wrote:
>
> On Dec 20, 2012, at 10:01 AM, Jessica Streicher wrote:
>
>> Really must have been unclear at some point, sorry.
>
> Hasn't it become abundantly clear that this would have progress farther
had you post a complete example?
>
> --
> David.
>>
>> William, thats interesting, but not really helping the main problem,
which is: how to do
>>
>>> l[[ as.character(grid[1, ]) ]] <- 1
>>
>> without having initialized the list in the loop before.
>>
>> Well, or how to initialize it without having to do the loop thing,
because the loop stuff can only be done for a specific set of parameter vectors.
But those change, and i don't want to have to write another loop construct
every time for the new version.
>>
>> I want to say: hey, i have these vectors here with these values (my
parameters), could you build me that nested list structure (tree - whatever)
from it? And the function will give me that structure whatever i give it without
me needing to intervene in form of changing the code.
>>
>> -------------- Clarification -----------------
>>
>> First: i am not computing statistics over the parameters. I'm
computing stuff from other data, and the computation is affected by the
parameters.
>>
>> I am computing classifiers for different sets of parameters for those
classifiers. So the result of doSomething() isn't a simple value. Its
usually a list of 6 lists (doing cross validation), which in turn have the
classifier object, some statistics of the classifier (e.g what was
missclassified), and the subsets of data used in them.
>> That doesn't really fit in a data.frame, hence the use of lists. I
want the nested lists because it helps me find stuff in the object browser
faster, and because all my other code is already geared towards it. If i had the
time i might still go for a flat structure that everyone keeps telling me to use
(got a few mails off the list),
>> but i really haven't the time.
>>
>> If theres no good way i'll just keep things as they are now.
>>
>>
>> On 20.12.2012, at 18:37, William Dunlap wrote:
>>
>>> Arranging data as a list of lists of lists of lists [...] of scalar
values generally
>>> will lead to slow and hard-to-read R code, mainly because R is
designed to
>>> work on long vectors of simple data. If you were to start over,
consider constructing
>>> a data.frame with one column for each attribute. Then tools like
aggregate and
>>> the plyr functions would be useful.
>>>
>>> However, your immediate problem may be solved by creating your
'grid' object
>>> as a data.frame of character, not factor, columns because
as.character works differently
>>> on lists of scalar factors and lists of scalar characters. Usually
as.<mode>(x), when
>>> x is a list of length-1 items, gives the same result as
as.<mode>(unlist(x)), but not when
>>> x is a list of length-1 factors:
>>>
>>>> height<-c("high", "low")
>>>> width<-c("slim", "wide")
>>>> gridF <- expand.grid(height, width, stringsAsFactors=FALSE)
>>>> gridT <- expand.grid(height, width, stringsAsFactors=TRUE)
>>>> as.character(gridF[1,])
>>> [1] "high" "slim"
>>>> as.character(gridT[1,])
>>> [1] "1" "1"
>>>> as.character(unlist(gridT[1,])) # another workaround
>>> [1] "high" "slim"
>>>
>>> Your example was not self-contained so I changed the call to
doSomething() to paste(h,w,sep="/"):
>>>
>>> height<-c("high", "low")
>>> width<-c("slim", "wide")
>>>
>>> l <- list()
>>> for(h in height){
>>> l[[h]] <- list()
>>> for(w in width){
>>> l[[h]][[w]] <- paste(h, w, sep="/") #
doSomething()
>>> }
>>> }
>>>
>>> grid <- expand.grid(height, width, stringsAsFactors=FALSE)
>>> as.character(grid[1,])
>>> # [1] "high" "slim", not the [1] "1"
"1" you get with stringsAsFactors=TRUE
>>> l[[ as.character(grid[1, ]) ]]
>>> # [1] "high/slim"
>>> l[[ as.character(grid[1, ]) ]] <- 1
>>> l[[ as.character(grid[1, ]) ]]
>>> # [1] 1
>>>
>>> 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 Jessica Streicher
>>>> Sent: Thursday, December 20, 2012 8:43 AM
>>>> To: Chris Campbell
>>>> Cc: R help
>>>> Subject: Re: [R] Filling Lists or Arrays of variable dimensions
>>>>
>>>> Aggregate is highly confusing (and i would have appreciated if
you used my example
>>>> instead, i don't get it to do anything sensible on my
stuff).
>>>>
>>>> And this seems not what i asked for anyway. This may be a named
list but not named and
>>>> structured as i want it at all.
>>>>
>>>> happy Christmas too
>>>>
>>>> On 20.12.2012, at 15:48, Chris Campbell wrote:
>>>>
>>>>> Dear Jessica
>>>>>
>>>>> Aggregate is a function that allows you to perform loops
across multiple variables.
>>>>>
>>>>> tempData <- data.frame(height = rnorm(20, 100, 10),
>>>>> width = rnorm(20, 50, 5),
>>>>> par1 = rnorm(20))
>>>>>
>>>>> tempData$htfac <- cut(tempData$height, c(0, 100, 200))
>>>>> tempData$wdfac <- cut(tempData$width, c(0, 50, 100))
>>>>>
>>>>> doSomething <- function(x) { mean(x) }
>>>>>
>>>>> out <- aggregate(tempData["par1"],
tempData[c("htfac", "wdfac")], doSomething)
>>>>>
>>>>> # out is a data frame; this is a named list.
>>>>> # use as.list to remove the data.frame class
>>>>>
>>>>>> as.list(out)
>>>>>
>>>>> $htfac
>>>>> [1] (0,100] (100,200] (0,100] (100,200]
>>>>> Levels: (0,100] (100,200]
>>>>>
>>>>> $wdfac
>>>>> [1] (0,50] (0,50] (50,100] (50,100]
>>>>> Levels: (0,50] (50,100]
>>>>>
>>>>> $par1
>>>>> [1] -1.0449563 -0.3782483 -0.9319105 0.8837459
>>>>>
>>>>>
>>>>
>>>>>
>>>>> I believe you are seeing an error similar to this one:
>>>>>
>>>>>> out[[1:3]] <- 1
>>>>> Error in `[[<-`(`*tmp*`, i, value = value) :
>>>>> recursive indexing failed at level 2
>>>>>
>>>>> This is because double square brackets for lists can only
set a single list element at
>>>> once; grid[1, ] is longer.
>>>>
>>>>>
>>>>> Happy Christmas
>>>>>
>>>>> Chris
>>>>>
>>>>>
>>>>> Chris Campbell
>>>>> Tel. +44 (0) 1249 705 450 | Mobile. +44 (0) 7929 628 349
>>>>> mailto:ccampbell at mango-solutions.com |
http://www.mango-solutions.com
>>>>> Mango Solutions
>>>>> 2 Methuen Park
>>>>> Chippenham
>>>>> Wiltshire
>>>>> SN14 OGB
>>>>> UK
>>>>>
>>>>> -----Original Message-----
>>>>> From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf
>>>> Of Jessica Streicher
>>>>> Sent: 20 December 2012 12:46
>>>>> To: R help
>>>>> Subject: [R] Filling Lists or Arrays of variable dimensions
>>>>>
>>>>> Following problem:
>>>>>
>>>>> Say you have a bunch of parameters and want to produce
results for all combinations
>>>> of those:
>>>>>
>>>>> height<-c("high","low")
>>>>> width<-c("slim","wide")
>>>>>
>>>>> then what i used to do was something like this:
>>>>>
>>>>> l<-list()
>>>>> for(h in height){
>>>>> l[[h]]<-list()
>>>>> for(w in width){
>>>>> l[[h]][[w]] <- doSomething()
>>>>> }
>>>>> }
>>>>>
>>>>> Now those parameters aren't always the same. Their
number can change and the
>>>> number of entries can change, and i'd like to have one code
that can handle all
>>>> configurations.
>>>>>
>>>>> Now i thought i could use expand.grid() to get all
configurations ,and than iterate over
>>>> the rows, but the problem then is that i cannot set the values
in the list like above.
>>>>>
>>>>> grid<-expand.grid(height,width)
>>>>> l[[as.character(grid[1,])]] <-1
>>>>> Error in `[[<-`(`*tmp*`, as.character(grid[1, ]), value
= 1) :
>>>>> no such index at level 1
>>>>>
>>>>> This will only work if the "path" for that is
already existent, and i'm not sure how to
>>>> build that in this scenario.
>>>>>
>>>>> I then went on and built an array instead lists of lists,
but that doesn't help either
>>>> because i can't access the array with what i have in the
grids row - or at least i don't
>>>> know how.
>>>>>
>>>>> Any ideas?
>>>>>
>>>>> I'd prefer to keep the named lists since all other code
is built towards this.
>>>>> ______________________________________________
>>>>> 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.
>>>>>
>>>>> --
>>>>>
>>>>> LEGAL NOTICE
>>>>>
>>>>> This message is intended for the use of the named
recipient(s) only and may contain
>>>>> confidential and / or privileged information. If you are
not the intended recipient,
>>>> please
>>>>> contact the sender and delete this message. Any
unauthorised use of the information
>>>>> contained in this message is prohibited.
>>>>>
>>>>> Mango Business Solutions Limited is registered in England
under No. 4560258 with its
>>>>> registered office at Suite 3, Middlesex House, Rutherford
Close, Stevenage, Herts, SG1
>>>> 2EF,
>>>>> UK.
>>>>>
>>>>> PLEASE CONSIDER THE ENVIRONMENT BEFORE PRINTING THIS EMAIL
>>>>>
>>>>
>>>> ______________________________________________
>>>> 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.
>>
>> ______________________________________________
>> 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
> Alameda, CA, USA
>
------------------------------
Message: 58
Date: Fri, 21 Dec 2012 19:46:17 +0900
From: Pascal Oettli <kridox at ymail.com>
To: saumya Joshi <saumyaj2008 at yahoo.com>
Cc: r-help at r-project.org
Subject: Re: [R] How to run chaid in R
Message-ID: <50D43DF9.6090102 at ymail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
https://stat.ethz.ch/pipermail/r-help/2009-August/209752.html
Le 21/12/2012 18:07, saumya Joshi a ?crit :> Could you please let me know how to run chaid in R.
>
>
> Thanks,
> Saumyha
> [[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.
>
------------------------------
_______________________________________________
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.
End of R-help Digest, Vol 118, Issue 21
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