[R] [newbie] aggregating table() results and simplifying code with loop
Rui Barradas
ruipbarradas at sapo.pt
Wed Sep 19 01:33:11 CEST 2012
Hello,
Inline
Em 18-09-2012 23:42, Davide Rizzo escreveu:
> Hi dear R-helpers,
>
> I really appreciate your "coding the answers" to (my) questions.
> I am now in the situation to get results in a very shorter time and
> with a proper code.
>
> +++++ the study (summary) +++++++++++++++++++++
>
> In (short) response to the question by John, the global target of the
> analysis is to identify the dynamics of crop sequences in a given
> region. The spatial grain is the elementary watershed (as defined by
> the local water agency). The temporal grain is a 5 year period (it
> allows, according to previous analyses, to grasp the major crop
> sequences for the study area). The input data is a grid of points
> where the land cover has been monitored since the 80's up to now (with
> a couple of interruptions). The first part of the analysis was aimed
> at characterizing crop sequences and their occurrences in the
> different watersheds.
> The step of the analysis for what I'm asking your help is aimed at
> calculating the return time of the most relevant crops (from an
> agronomic point of view), on which operate then a clustering. Raw
> attempts I've tried so far with other methods appeared to give
> promising results, so I've decided to improve the approach using R.
> Here is where you come in.
> +++++++++++++++++++++++++++++++++++++++++++
>
> ++++++ (unsolved) questions +++++++++++++++++++
>
> The proposal by John is clear to me, probably because his way of
> coding is closer to my capability to understand. The solution by Rui
> looks interesting, complete and effective (few elementary functions
> and reduced time to have the results to be used in the other steps of
> the analysis).
>
> Nevertheless I'm still in trouble because I'm not used with function
> (that's one of the reasons I'm here).
> The following questions will sound naive to you, but I'm not able to
> decrypt Rui's code without asking again your help. Basic manuals (like
> "R Language Definition" ch. 4, or "The R Inferno" ch. 5) were not
> sufficient for me to understand how "w", "DF", "Mat", "WS" and
> "currcols" are defined.
A function's arguments are defined, surprise!, in the function's
definition. See R-intro chap. 10 and R-Inferno chap. 6.
Example:
f <- function(x){
y <- 2*x + 1
y
}
x <- 1
f(2) # returns 5
This is because the 'x' outside the function is not the same as the 'x'
inside the function. In the function definition I can choose any name I
want, and then use that name in the function's body.
(Actually it's a bit more complicated because if a function uses a
variable not passed to nor defined in the function, R will look for it
in the caller's environment, and goes up until the global environment.
It throws an error only if it's nowhere to be found.)
Chap. 6 of the R-inferno is about global assignments, also saying that
in R if a function changes its arguments the modified version has
nothing to do with the argument's value outside the function. Uunless
it's returned, on exit this new value is lost. This is the case of
example 1, variable 'x'.
This behavior is very usefull because it means that side effects are
unlikely to occur. That's what P. Burns is talking about when he says
that "Surprise in movies and novels is good. Surprise in computer code
is bad." To understand a function look at the way it is called, and to
what happens in it. Forget almost all of the rest, the exception being
what is passed to it.
Finally, like with everything, it takes some time to be comfortable with
R. And practice.
Have fun.
Rui Barradas
> In other words, I see that the five embedded functions Rui has
> proposed call for the above mentioned arguments, but I'm not able to
> understand at which moment these arguments are defined.
> +++++++++++++++++++++++++++++++++++++++++++
>
> Everything flows without warnings, so I have the bad feeling to find
> myself less smart than R...
> That not a big problem, but having not understood the arguments, I do
> not understand the functions (so, the results).
> Thanks in advance for meeting this call for some extra-help...
>
> Take care,
> Dd
>
> ***********************************************************
> Davide Rizzo
> website :: http://sites.google.com/site/ridavide/
>
>
> On Tue, Sep 18, 2012 at 5:08 PM, Rui Barradas <ruipbarradas at sapo.pt> wrote:
>> Hello,
>> Em 18-09-2012 15:29, John Kane escreveu:
>>
>>> Looks very interesting and as I said you're a much better progamer than I am. I get headaches using lapply()!
>>
>> Thanks!
>> As for lapply, if you understand apply you'll understand lapply. With some differences, the principle is the same.
>>
>>> I am going to have to spend some time stepping through the functions to really see what you are doing.
>>
>> I've tried to keep each function simple, but it can become complicated to follow the call tree down to f1.
>>
>>
>>> However if I understand the output, for example one can simply aggreate the information by Crop and Period in each element of the list to get the corresponding sums for each of the desired patterns?
>>>
>>> Thus for example in result[[1]] we get all the results for condition 19 (crops) from wanted?
>>
>> Yes, or at least it's supposed to. And I've kept in separate list elements precisely to have simplified access to each combination of Crop and Period.
>> (Condition 19, the last one, comes first because split sorts its output by list element name, and 'crop' is the first.)
>>
>> Rui Barradas
>>
>>
>>>
>>> John Kane
>>> Kingston ON Canada
>>>
>>>
>>>> -----Original Message-----
>>>> From: ruipbarradas at sapo.pt
>>>> Sent: Mon, 17 Sep 2012 16:04:15 +0100
>>>> To: jrkrideau at inbox.com, ridavide at gmail.com, jrkrideau at inbox.com
>>>> Subject: Re: [R] [newbie] aggregating table() results and simplifying
>>>> code with loop
>>>>
>>>> Hello,
>>>>
>>>> Now I believe I've got it. (So-so believe.)
>>>> ddply is a good idea, in my first post I was using xtabs to the same
>>>> effect, but ddply makes it a lot easier.
>>>> I had made a big mistake, though. I thought that only sequences of FALSE
>>>> were valid, hence rle(). In a follow-up post, Davide listed all
>>>> combinations of T/F that matter. The code below uses them to create a df
>>>> of cases to count with ddply. The creation is done by merge, on the T/F
>>>> columns (function f1) and the rest is just to apply to 6 periods of 5
>>>> years each, after applying to covers, after applying to years of crop
>>>> type.
>>>> Sounds confusing, and it probably is but I've separated all of it in
>>>> small functions.
>>>> Each of the functions is in fact very simple, and all one needs is to
>>>> remember that the inner most function is reached after a series of
>>>> *apply statements, doing one thing at a time.
>>>>
>>>>
>>>> #------------------------------------------------------------------------------
>>>> # data.frame of target sequences of T/F per crop type and years
>>>> # (from an earlier post)
>>>>
>>>> wanted <-
>>>> structure(list(V2 = c(TRUE, FALSE, TRUE, FALSE, FALSE, TRUE,
>>>> FALSE, FALSE, FALSE, TRUE, TRUE, FALSE, TRUE, TRUE, TRUE, FALSE,
>>>> TRUE, FALSE, TRUE), V3 = c(FALSE, FALSE, FALSE, TRUE, FALSE,
>>>> FALSE, TRUE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE, FALSE, TRUE,
>>>> FALSE, TRUE, TRUE, TRUE), V4 = c(FALSE, FALSE, FALSE, FALSE,
>>>> FALSE, FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE, TRUE, TRUE,
>>>> TRUE, TRUE, TRUE, TRUE, FALSE), V5 = c(FALSE, FALSE, FALSE, FALSE,
>>>> TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE, TRUE,
>>>> FALSE, TRUE, FALSE, TRUE, TRUE), V6 = c(FALSE, TRUE, TRUE, FALSE,
>>>> FALSE, FALSE, TRUE, FALSE, FALSE, TRUE, TRUE, TRUE, FALSE, TRUE,
>>>> TRUE, TRUE, FALSE, FALSE, TRUE), V7 = c(" return", " return",
>>>> " return", " return", " return", " return", " return", " return",
>>>> " return", " return", " mono-succession", " mono-succession",
>>>> " mono-succession", " mono-succession", " mono-succession","
>>>> mono-succession",
>>>> " mono-succession", " mono-succession", " crops"), V8 = c(5L,
>>>> 5L, 4L, 4L, 4L, 3L, 3L, 3L, 2L, 2L, 5L, 4L, 4L, 3L, 3L, 3L, 3L,
>>>> 3L, 2L)), .Names = c("V2", "V3", "V4", "V5", "V6", "V7", "V8"
>>>> ), row.names = c(NA, -19L), class = "data.frame")
>>>>
>>>> want <- split(wanted, wanted$V7)
>>>>
>>>> #--------------------------------------------------------------------
>>>> # The functions go from f5 down to f1 (f5 calls f4, f4 calls f3, etc.)
>>>> #
>>>> f1 <- function(DF, Mat, currcols, WS){
>>>> mcols <- names(T80[, ycols])[currcols] # names for 'merge'
>>>> names(DF)[1:5] <- mcols
>>>> m <- merge(DF, data.frame(Mat[, mcols], WS = WS))
>>>> ddply(m, .(WS), summarize, length(V8))
>>>> }
>>>> f2 <- function(w, tf, WS){
>>>> l1 <- lapply(yrs, function(yy) t(f1(w, tf, yy, WS)))
>>>> l2 <- lapply(l1, function(x){
>>>> nms <- as.character(x["WS",])
>>>> resline[ nms ] <- x[2, ]
>>>> resline})
>>>> res <- do.call(rbind, l2)
>>>> data.frame(res)
>>>> }
>>>> f3 <- function(Cover, w){
>>>> tf <- T80[, ycols] == Cover
>>>> inx <- as.vector(apply(tf, 1, function(.x) any(.x)))
>>>> tf <- tf[inx, ]
>>>> WS <- T80$WS[inx]
>>>> # Special care with empty sets
>>>> if(sum(tf) > 0){
>>>> res <- f2(w, tf, WS)
>>>> na <- as.vector(apply(res, 1, function(.x) all(is.na(.x))))
>>>> res <- res[!na, ]
>>>> if(!is.null(res) && nrow(res) > 0){
>>>> res$Cover <- Cover
>>>> res$Period <- (1:6)[!na]
>>>> }else res <- NULL
>>>> }else res <- NULL
>>>> res
>>>> }
>>>> f4 <- function(w){
>>>> res <- do.call(rbind, lapply(covers, f3, w))
>>>> # Special care with empty sets
>>>> if(!is.null(nrow(res)) && nrow(res) > 0){
>>>> res <- data.frame(res)
>>>> res$Years <- w$V8[1]
>>>> }else res <- NULL
>>>> res
>>>> }
>>>> f5 <- function(w){
>>>> sp <- split(w, w$V8)
>>>> res <- do.call( rbind, lapply(sp, f4) )
>>>> res <- data.frame(res)
>>>> res
>>>> }
>>>>
>>>> T80 <- read.table("sample.txt", header = TRUE, sep = ";")
>>>>
>>>> ycols <- grep("y", names(T80))
>>>> ws <- unique(T80$WS)
>>>> covers <- as.character(unique(unlist(T80[ycols])))
>>>> yrs <- lapply(0:5, `+`, 1:5)
>>>> resline <- rep(NA, length(ws))
>>>> names(resline) <- ws
>>>>
>>>> result <- lapply(want, f5)
>>>>
>>>>
>>>> (Ok, maybe two or three things at a time.)
>>>>
>>>> I hope this is it!
>>>> Have fun.
>>>>
>>>> Rui Barradas
>>>>
>>>> Em 17-09-2012 14:19, John Kane escreveu:
>>>>> Comments in-line below.
>>>>>
>>>>> Sorry to be so long getting back to you but sleep intervened.
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: ridavide at gmail.com
>>>>>> Sent: Sun, 16 Sep 2012 21:24:15 +0200
>>>>>> To: jrkrideau at inbox.com
>>>>>> Subject: Re: [R] [newbie] aggregating table() results and simplifying
>>>>>> code with loop
>>>>>>
>>>>>> Thank you John,
>>>>>>
>>>>>> you are giving me two precious tips (in addition, well explained!):
>>>>>> 1. to use the package plyr (I didn't know it before, but it seems to
>>>>>> make the deal!)
>>>>>> 2. a smart and promising way to use it
>>>>>>
>>>>>> I can finally plot the partial results, to have a first glance and
>>>>>> compare to them
>>>>>>
>>>>>> ==========================================================
>>>>>>
>>>>>> # once the sequences for a given crop have been assembled in a
>>>>>> dataframe (e.g., maizedata)
>>>>>> library(latticeExtra) # load the package for "improved" graphics
>>>>>> dotplot(mzcount$crop_pattern) # to plot the occurrence of all the
>>>>>> retrieved sequences
>>>>>>
>>>>>> #once the target pattern have been subset (e.g., m51)
>>>>>> dotplot(m51$WS ~ m51$count) # to plot the occurrence of the target
>>>>>> pattern(s) per watershed
>>>>> Ah, so that's what WS stands for! Do you have an abstract or short
>>>>> summary of what you are doing in English or French? My Itallian is
>>>>> limited to about 3 words or what I can guess from French/Latin.
>>>>>
>>>>> I think that you are misunderstanding what is happening in m51. It is
>>>>> just summarizing the total counts across those two conditions. I think
>>>>> either I made a logic error or was not understanding what was needed. In
>>>>> any case the dotplot is not plotting the actual occurances but the
>>>>> number of times the crop_pattern was found. The count is the actual
>>>>> number of occurances per WS per crop_pattern
>>>>>
>>>>>
>>>>> Have a look at my new effort. it is still ugly but I think it more
>>>>> accurately supplies some of what you want.
>>>>>
>>>>> Two caveats : 1. This is still very rough and an better programer may
>>>>> have a better approach.
>>>>> 2. I used the package ggplot2 to do the graphs. One more thing to learn
>>>>> but I am not used to lattice and I am used to ggplot2. Rather than spend
>>>>> a lot of time with lattice or
>>>>> 2. The last faceted plots are not intended to be of real use, just my
>>>>> quick look to see if anything looked like I expected. A bit of thinking
>>>>> probably would give somethimg much better
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> ==========================================================
>>>>>>
>>>>>> This help me retrieving all the possible patterns for the different
>>>>>> land covers. Hence, you made me able to improve the subset of
>>>>>> patterns.
>>>>>>
>>>>>> Tomorrow morning I'm going to test the tips for all the land covers
>>>>>> for all the 5years time-periods. Even if still labour-intensive, the
>>>>>> solution you propose it's surely a steady improvement.
>>>>>> Now only the second question remains: is there a way "to clean" this
>>>>>> approach?... or probably not ?...
>>>>> Yes I suspect that there are lots of ways to 'clean' the process and
>>>>> automate it so that it would apply to all three data sets quite easily.
>>>>> Some I think I can help with and some you may need other people's help.
>>>>>
>>>>> For example, once we have a working model to handle one or two
>>>>> conditions It should be relatively easy to use an apply() or a loop to
>>>>> handle all of them and so on..
>>>>>
>>>>> Well, I'm off to work now so I probably won't be able to get back to
>>>>> much before late evening my time ( probably after you are asleep) I
>>>>> think I'm 6 hours ahead of you.
>>>>>
>>>>> ##===================Revised approach====================
>>>>> # load the various packages (plyr, latticeExtra, ggplot2, reshape2)
>>>>> library(plyr)
>>>>> library(latticeExtra)
>>>>> library(ggplot2)
>>>>> library(reshape2)
>>>>>
>>>>> # sample data
>>>>> T80<- read.csv("/home/john/rdata/sample.csv", header = TRUE, sep = ";")
>>>>> # Davide's actual read statement
>>>>> # T80<-read.table(file="C:/sample.txt", header=T, sep=";")
>>>>>
>>>>> # Looking for Maize
>>>>> pattern <- c("2Ma", "2Ma","2Ma", "2Ma","2Ma")
>>>>>
>>>>> # one row examples to see that is happening
>>>>> T80[1,3:7]
>>>>> T80[1, 3:7] == pattern
>>>>>
>>>>> T80[405, 3:7]
>>>>> T80[405, 3:7] == pattern
>>>>>
>>>>> T80[55, 3:7] == pattern
>>>>>
>>>>> # now we apply the patterns to the entire data set.
>>>>> pp1 <- T80[, 3:7] == pattern
>>>>>
>>>>> # paste the TRUEs and FALSEs together to form a single variable
>>>>> concatdat <- paste(pp1[, 1], pp1[, 2], pp1[, 3], pp1[, 4],pp1[,5] ,
>>>>> sep = "+")
>>>>>
>>>>> # Assmble new data frame.
>>>>> maizedata <- data.frame(T80$WS, concatdat)
>>>>> names(maizedata) <- c("WS", "crop_pattern")
>>>>> str(maizedata)
>>>>>
>>>>> maizedata$crop_pattern <- as.character(maizedata$crop_pattern)
>>>>>
>>>>> pattern_count <- ddply(maizedata, .(crop_pattern), summarize, npattern
>>>>> = length(crop_pattern))
>>>>> str(pattern_count)
>>>>> head(pattern_count); dim(pattern_count) # quick look at data.frame and
>>>>> its size.
>>>>>
>>>>> # FALSE+FALSE+FALSE+FALSE+FALSE accounts for 21,493 values.
>>>>>
>>>>> which(pattern_count$npattern == max(pattern_count$npattern)) # this
>>>>> does the same as looking at the data
>>>>>
>>>>> # not needed here but useful for larger datasets.
>>>>>
>>>>> # If we graph pattern_count as it stands we lose any useful detail
>>>>> because of that outlier.
>>>>> p <- ggplot(pattern_count , aes(crop_pattern, npattern )) +
>>>>> geom_point() +
>>>>> coord_flip()
>>>>> p
>>>>>
>>>>> (pattern1 <- pattern_count[-1,]) # Drop the offending
>>>>> FALSE+FALSE+FALSE+FALSE+FALSE
>>>>> dim(pattern1) # Okay now we have the maize patterns, without the WS who
>>>>> had no maize at all.
>>>>>
>>>>> p <- ggplot(pattern1 , aes(crop_pattern, npattern )) + geom_point()
>>>>> +
>>>>> coord_flip()
>>>>> p
>>>>>
>>>>>
>>>>> newmaize <- subset(maizedata, maizedata$crop_pattern !=
>>>>> "FALSE+FALSE+FALSE+FALSE+FALSE")
>>>>> dim(newmaize) ; head(newmaize)
>>>>> str(newmaize)
>>>>>
>>>>> summaize_by_WS <- ddply(newmaize, .(WS), summarize, crop_pattern_ws =
>>>>> length(crop_pattern))
>>>>>
>>>>> p <- ggplot( summaize_by_WS , aes(summaize_by_WS )) + geom_point +
>>>>> coord_flip()
>>>>> p
>>>>>
>>>>> summaize_by_WS_and_crop <- ddply(newmaize, .(WS, crop_pattern),
>>>>> summarize, crop_pattern_ws = length(crop_pattern))
>>>>>
>>>>> # crappy graph but just try to see what we might get. probablly need to
>>>>> subset or use better grid layout.
>>>>> p <- ggplot( summaize_by_WS_and_crop , aes(crop_pattern,
>>>>> crop_pattern_ws )) + geom_point() +
>>>>> coord_flip() + facet_grid(WS ~ . )
>>>>> p
>>>>>
>>>>> # save the last graph to look at it in a graphics package== still
>>>>> terrible
>>>>> ggsave( "/home/john/Rjunk/crop.png")
>>>>>
>>>>> ##
>>>>>> Thanks again for the help.
>>>>>> Cheers,
>>>>>> Dd
>>>>>>
>>>>>> ***********************************************************
>>>>>> Davide Rizzo
>>>>>> website :: http://sites.google.com/site/ridavide/
>>>>>>
>>>>>>
>>>>>> On Sun, Sep 16, 2012 at 8:24 PM, John Kane <jrkrideau at inbox.com> wrote:
>>>>>>> Hi Davide,
>>>>>>>
>>>>>>> I had some time this afternoon and I wonder if this approach is llkely
>>>>>>> to get the results you want? As before it is not complete but I think
>>>>>>> it holds promise.
>>>>>>>
>>>>>>> On the other hand Rui is a much better programer than I am so he may
>>>>>>> have a much cleaner solution. My way still looks labour-intensive at
>>>>>>> the moment.
>>>>>>>
>>>>>>> I am using the plyr package which you will probably have to install.
>>>>>>> load.packages("plyr") should do it.
>>>>>>> ==========================================================
>>>>>>> # load the plyr package -
>>>>>>> library(plyr)
>>>>>>>
>>>>>>> # sample data
>>>>>>> T80<- read.csv("/home/john/rdata/sample.csv", header = TRUE, sep =
>>>>>>> ";")
>>>>>>> # Davide's actual read statement
>>>>>>> # T80<-read.table(file="C:/sample.txt", header=T, sep=";")
>>>>>>>
>>>>>>> # Looking for Maize
>>>>>>> pattern <- c("2Ma", "2Ma","2Ma", "2Ma","2Ma")
>>>>>>>
>>>>>>> # one row examples to see that is happening
>>>>>>> T80[1,3:7]
>>>>>>> T80[1, 3:7] == pattern
>>>>>>>
>>>>>>> T80[405, 3:7]
>>>>>>> T80[405, 3:7] == pattern
>>>>>>>
>>>>>>> T80[55, 3:7] == pattern
>>>>>>>
>>>>>>> # now we apply the patterns to the entire data set.
>>>>>>> pp1 <- T80[, 3:7] == pattern
>>>>>>>
>>>>>>> # paste the TRUEs and FALSEs together to form a single variable
>>>>>>> concatdat <- paste(pp1[, 1], pp1[, 2], pp1[, 3], pp1[, 4],pp1[,5] ,
>>>>>>> sep = "+")
>>>>>>>
>>>>>>> # Assmble new data frame.
>>>>>>> maizedata <- data.frame(T80$WS, concatdat)
>>>>>>> names(maizedata) <- c("WS", "crop_pattern")
>>>>>>>
>>>>>>> mzcount <- ddply(maizedata, .(WS, crop_pattern), summarize, count =
>>>>>>> length(crop_pattern))
>>>>>>> mzcount # This is all the data not just the relevant maise patterns
>>>>>>>
>>>>>>> # This seems to be getting us somewhere though we are not not there
>>>>>>> yet
>>>>>>> # Does this subset look like we are going in the right direction?
>>>>>>> m51 <- subset(mzcount,
>>>>>>> mzcount$crop_pattern == "FALSE+FALSE+FALSE+FALSE+TRUE"
>>>>>>> | mzcount$crop_pattern == "TRUE+FALSE+FALSE+FALSE+FALSE")
>>>>>>>
>>>>>>> m51 <- ddply(m51, .(WS), summarize, count = sum(count))
>>>>>>> m51
>>>>>>> =================================================================
>>>>>>>
>>>>>>> John Kane
>>>>>>> Kingston ON Canada
>>>>>>>
>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: ridavide at gmail.com
>>>>>>>> Sent: Sat, 15 Sep 2012 19:00:29 +0200
>>>>>>>> To: jrkrideau at inbox.com, ruipbarradas at sapo.pt
>>>>>>>> Subject: Re: [R] [newbie] aggregating table() results and simplifying
>>>>>>>> code with loop
>>>>>>>>
>>>>>>>> Thanks Rui, thanks John for your very different solutions.
>>>>>>>>
>>>>>>>> I'll try to break my questions into smaller steps following your
>>>>>>>> tips.
>>>>>>>> However, not everything is clear for me... so before giving you a
>>>>>>>> feed-back I need to study further your answers. For the moment I
>>>>>>>> could
>>>>>>>> specify that I'm looking for the following 19 patterns:
>>>>>>>>
>>>>>>>> 1. True, False, False, False, False # return period of 5 years (1/2)
>>>>>>>> 2. False, False, False, False, True # return period of 5 years (2/2)
>>>>>>>> 3. True, False, False, False, True # return period of 4 years (1/3)
>>>>>>>> 4. False, True, False, False, False # return period of 4 years (2/3)
>>>>>>>> 5. False, False, False, True, False # return period of 4 years (3/3)
>>>>>>>> 6. True, False, False, True, False # return period of 3 years (1/3)
>>>>>>>> 7. False, True, False, False, True # return period of 3 years (2/3)
>>>>>>>> 8. False, False, True, False, False # return period of 3 years (3/3)
>>>>>>>> 9. False, True, False, True, False # return period of 2 years (1/2)
>>>>>>>> 10. True, False, True, False, True # return period of 2 years (1/2)
>>>>>>>> 11. True, True, True, True, True # mono-succession of 5 years
>>>>>>>> 12. False, True, True, True, True # mono-succession of 4 years (1/2)
>>>>>>>> 13. True, True, True, True, False # mono-succession of 4 years (2/2)
>>>>>>>> 14. True, False, True, True, True # mono-succession of 3 years (1/5)
>>>>>>>> 15. True. True. True. False, True # mono-succession of 3 years (2/5)
>>>>>>>> 16. False, False, True, True, True # mono-succession of 3 years (3/5)
>>>>>>>> 17. True, True, True, False, False # mono-succession of 3 years (4/5)
>>>>>>>> 18. False, True, True, True, False # mono-succession of 3 years (5/5)
>>>>>>>> 19. True, True, False, True, True # crops repeated two years
>>>>>>>>
>>>>>>>> In particular, I want to apply all these 19 patterns to 7 (out of 11)
>>>>>>>> land covers: 2BC, 2Co, 2Ma, 2We, 2MG, 2ML, 2PG. The pattern are so
>>>>>>>> structured: True means presence of a given land cover (iteratively,
>>>>>>>> one of the seven listed above), False means any other land-cover
>>>>>>>> (amidst the remainder 10).
>>>>>>>>
>>>>>>>> Thanks again for any further help.
>>>>>>>> Greetings,
>>>>>>>> Dd
>>>>>>>>
>>>>>>>> ***********************************************************
>>>>>>>> Davide Rizzo
>>>>>>>> website :: http://sites.google.com/site/ridavide/
>>>>>>>>
>>>>>>>>
>>>>>>>> On Sat, Sep 15, 2012 at 5:51 PM, John Kane <jrkrideau at inbox.com>
>>>>>>>> wrote:
>>>>>>>>> I have not seen any replies to your questions so I will suggest an
>>>>>>>>> approach that may work if I can get a function to work.
>>>>>>>>>
>>>>>>>>> If I understand what you want, you have a pattern something like
>>>>>>>>> this:
>>>>>>>>> pattern1 <- c("2Ma", "no2Ma","no2Ma", "no2Ma","no2Ma")
>>>>>>>>> pattern2 <- c("no2Ma", 'no2Ma', "no2Ma", "no2Ma", "2Ma")
>>>>>>>>>
>>>>>>>>> for each five year period where 2Ma stands to Maize, one of 11
>>>>>>>>> different
>>>>>>>>> grains
>>>>>>>>> 1AU 2BC 2Co 2Ma 2MG 2ML 2oc 2PG 2SA 2We 3sN
>>>>>>>>>
>>>>>>>>> and what you want to know is if each year gives a pattern like
>>>>>>>>>
>>>>>>>>> check1 <- c(TRUE, FALSE, FALSE, FALSE, FALSE)
>>>>>>>>> check2 <- c(FALSE, FALSE, FALSE, FALSE, TRUE)
>>>>>>>>>
>>>>>>>>> If I understand the patterns you only care for the two above, is
>>>>>>>>> that
>>>>>>>>> correct?
>>>>>>>>>
>>>>>>>>> I am running out of time today but I think that this approach will
>>>>>>>>> get
>>>>>>>>> you started
>>>>>>>>> ===========================================================
>>>>>>>>>
>>>>>>>>> T80<-read.table(file="C:/sample.txt", header=T, sep=";")
>>>>>>>>>
>>>>>>>>> # Reminder of just what we want to get as a final result.
>>>>>>>>> check1 <- c(TRUE, FALSE, FALSE, FALSE, FALSE)
>>>>>>>>> check2 <- c(FALSE, FALSE, FALSE, FALSE, TRUE)
>>>>>>>>>
>>>>>>>>> pattern1 <- c("2Ma", "2Ma","2Ma", "2Ma","2Ma")
>>>>>>>>>
>>>>>>>>> # one row examples to see that is happening
>>>>>>>>> T80[1,3:7]
>>>>>>>>> T80[1, 3:7] == pattern1
>>>>>>>>>
>>>>>>>>> T80[405, 3:7]
>>>>>>>>> T80[405, 3:7] == pattern1
>>>>>>>>>
>>>>>>>>> # now we apply the patterns to the entire data set.
>>>>>>>>> pp1 <- T80[, 3:7] == pattern1
>>>>>>>>> pp2 <- T80[, 3:7] == pattern2
>>>>>>>>>
>>>>>>>>> # reassign the WS values so we know where the data is from
>>>>>>>>> WSnames <- rep(T80$WS, 2)
>>>>>>>>>
>>>>>>>>> # Assmble new data frame.
>>>>>>>>> maizedata <- data.frame(WSnames, rbind(pp1,pp2))
>>>>>>>>> ========================================================
>>>>>>>>>
>>>>>>>>> Now, assuming this runs for you and I have not made a serious
>>>>>>>>> mistake
>>>>>>>>> in
>>>>>>>>> logic, kyou should be able to do some subsetting (?subset) to
>>>>>>>>> extract
>>>>>>>>> only the
>>>>>>>>> check1 and check2 patterns above.
>>>>>>>>>
>>>>>>>>> This is where I ran into trouble as I don't have the time this
>>>>>>>>> morning
>>>>>>>>> to work out the subsetting conditions. It looks tricking and you
>>>>>>>>> probably need a couple of subsetting moves.
>>>>>>>>>
>>>>>>>>> It's not a pretty solutlion and, particularly, I expect someone
>>>>>>>>> could
>>>>>>>>> clean it up to make the subsetting easier or even unnecessary but I
>>>>>>>>> hope
>>>>>>>>> it helps.
>>>>>>>>>
>>>>>>>>> Once you have extracted what you want use apply() or perhaps the
>>>>>>>>> plyr
>>>>>>>>> package to aggregate the results.
>>>>>>>>>
>>>>>>>>> Repeat for all grains. Actually look into setting the whole thing
>>>>>>>>> up
>>>>>>>>> as
>>>>>>>>> a function. You should be able to write the program once as a
>>>>>>>>> function
>>>>>>>>> and do a loop or an apply() to do all 11 grains in one go.
>>>>>>>>>
>>>>>>>>> Best of luck.
>>>>>>>>>
>>>>>>>>> John Kane
>>>>>>>>> Kingston ON Canada
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> -----Original Message-----
>>>>>>>>>> From: ridavide at gmail.com
>>>>>>>>>> Sent: Thu, 13 Sep 2012 15:36:28 +0200
>>>>>>>>>> To: r-help at r-project.org
>>>>>>>>>> Subject: [R] [newbie] aggregating table() results and simplifying
>>>>>>>>>> code
>>>>>>>>>> with loop
>>>>>>>>>>
>>>>>>>>>> Dear all,
>>>>>>>>>> I'm looking for primary help at aggregating table() results and at
>>>>>>>>>> writing a loop (if useful)
>>>>>>>>>>
>>>>>>>>>> My dataset ( http://goo.gl/gEPKW ) is composed of 23k rows, each
>>>>>>>>>> one
>>>>>>>>>> representing a point in the space of which we know the land cover
>>>>>>>>>> over
>>>>>>>>>> 10 years (column y01 to y10).
>>>>>>>>>>
>>>>>>>>>> I need to analyse it with a temporal sliding window of 5 years (y01
>>>>>>>>>> to
>>>>>>>>>> y05, y02 to y06 and so forth)
>>>>>>>>>> For each period I'm looking for specific sequences (e.g., Maize,
>>>>>>>>>> -noMaize, -noMaize, -noMaize, -noMaize) to calculate the "return
>>>>>>>>>> time"
>>>>>>>>>> of principal land covers: barley (2BC), colza (2Co), maize (2Ma),
>>>>>>>>>> etc.
>>>>>>>>>> I define the "return time" as the presence of a given land cover
>>>>>>>>>> according to a given sequence. Hence, each return time could
>>>>>>>>>> require
>>>>>>>>>> the sum of different sequences (e.g., a return time of 5 years
>>>>>>>>>> derives
>>>>>>>>>> from the sum of [2Ma,no2Ma,no2Ma,no2Ma,no2Ma] +
>>>>>>>>>> [no2Ma,no2Ma,no2Ma,no2Ma,2Ma]).
>>>>>>>>>> I need to repeat the calculation for each land cover for each time
>>>>>>>>>> window. In addition, I need to repeat the process over three
>>>>>>>>>> datasets
>>>>>>>>>> (the one I give is the first one, the second one is from year 12 to
>>>>>>>>>> year 24, the third one from year 27 to year 31. So I have breaks in
>>>>>>>>>> the monitoring of land cover that avoid me to create a continuous
>>>>>>>>>> dataset). At the end I expect to aggregate the sum for each spatial
>>>>>>>>>> entity (column WS)
>>>>>>>>>>
>>>>>>>>>> I've started writing the code for the first crop in the first 5yrs
>>>>>>>>>> period (http://goo.gl/FhZNx) then copying and pasting it for each
>>>>>>>>>> crop
>>>>>>>>>> then for each time window...
>>>>>>>>>> Moreover I do not know how to aggregate the results of table(). (NB
>>>>>>>>>> sometimes I have a different number of WS per table because a given
>>>>>>>>>> sequence could be absent in a given spatial entity... so I have the
>>>>>>>>>> following warning msg: number of columns of result is not a
>>>>>>>>>> multiple
>>>>>>>>>> of vector length (arg 1)). Therefore, I'm "obliged" to copy&paste
>>>>>>>>>> the
>>>>>>>>>> table corresponding to each sequence....
>>>>>>>>>>
>>>>>>>>>> FIRST QUEST. How to aggregate the results of table() when the
>>>>>>>>>> number
>>>>>>>>>> of columns is different?
>>>>>>>>>> Or the other way around: Is there a way to have a table where each
>>>>>>>>>> row
>>>>>>>>>> reports the number of points per time return per WS? something like
>>>>>>>>>>
>>>>>>>>>> WS1 WS2 WS3 WS4 ... WS16 crop period
>>>>>>>>>> 23 15 18 43 ... 52 Ma5 01
>>>>>>>>>> 18 11 25 84 ... 105 Ma2 01
>>>>>>>>>> ... ... ... ... ... ... ... ...
>>>>>>>>>> ... ... ... ... ... ... Co5 01
>>>>>>>>>> ... ... ... ... ... ... ... ...
>>>>>>>>>> ... ... ... ... ... ... Ma5 02
>>>>>>>>>> ... ... ... ... ... ... ... ...
>>>>>>>>>> In this table each row should represent a return time for a given
>>>>>>>>>> land
>>>>>>>>>> cover a given period (one of the 6 time window of 5 years)?
>>>>>>>>>>
>>>>>>>>>> SECOND QUEST. Could a loop (instead of a modular copy/paste code)
>>>>>>>>>> improve the time/reliability of the calculation? If yes, could you
>>>>>>>>>> please indicate me some entry-level references to write it?
>>>>>>>>>>
>>>>>>>>>> I am aware this are newbie's questions, but I have not be able to
>>>>>>>>>> solve them using manuals and available sources.
>>>>>>>>>> Thank you in advance for your help.
>>>>>>>>>>
>>>>>>>>>> Greetings,
>>>>>>>>>> Dd
>>>>>>>>>>
>>>>>>>>>> PS
>>>>>>>>>> R: version 2.14.2 (2012-02-29)
>>>>>>>>>> OS: MS Windows XP Home 32-bit SP3
>>>>>>>>>>
>>>>>>>>>> *****************************
>>>>>>>>>> Davide Rizzo
>>>>>>>>>> post-doc researcher
>>>>>>>>>> INRA UR055 SAD-ASTER
>>>>>>>>>> website :: http://sites.google.com/site/ridavide/
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