Hi Janet: here is a start to give you the idea, now you need loop either use a "for" or one of the apply functions.
1. Preallocate new data (i am lazy so it is array, for example of size three. 2. order the data and set values. junk <- array(0, dim = c(2,3)) values <- c(10, 30, 50) junk[1, order(c(32, 11, 17))] <- values junk[1, ] [1] 50 10 30 This works because order() returns the index of the ordering, not the values. HTH, -Roy > On May 29, 2022, at 1:31 PM, Janet Choate <jsc....@gmail.com> wrote: > > I'm sorry if this has come across as a homework assignment!I was trying to > provide a simple example. > There are actually 38323 rows of data, each row is an observation of the > percent that each of those veg types occupies in a spatial unit - where > each line adds to 90 - and values are different every line. > I need a way to categorize the data, so I can reduce the number of unique > observations. > > So instead of 38323 unique observations - I can reduce this to > X number of High/Med/Low > X number of Med/Low/High > X number of Low/High/Med > etc... for all combinations > > I hope this makes it more clear...... > thank you all for your responses, > JC > > On Sun, May 29, 2022 at 1:16 PM Avi Gross via R-help <r-help@r-project.org> > wrote: > >> Tom, >> You may have a very different impression of what was asked! LOL! >> Unless Janet clarifies what seems a bit like a homework assignment, it >> seems to be a fairly simple and straightforward assignment with exactly >> three rows/columns and asking how to replace the variables, in a sense, by >> finding the high and low and perhaps thus identifying the medium, but to do >> this for each row without changing the order of the resulting data.frame. >> I note most techniques people have used focus on columns, not rows, but an >> all-numeric data.frame can be transposed, or converted to a matrix and >> later converted back. >> If this is HW, the question becomes what has been taught so far and is >> supposed to be used in solving it. Can they make their own functions >> perhaps to be called three times, once per row or column, to replace that >> row/column, or can they use some form of loop to iterate over the columns? >> Does it need to sort of be done in place or can they create gradually a >> second data.frame and then move the pointer to it and lots of other similar >> ideas. >> I am not sure, other than as a HW assignment, why this transformation >> would need to be done but of course, there may well be a reason. >> I note that the particular example shown just happens to create almost a >> magic square as the sum of rows and columns and the major diagonal happen >> to be 0, albeit the reverse diagonal is all 50's. >> Again, there are many solutions imaginable but the goal may be more >> specific and I shudder to supply one given that too often questions here >> are not detailed enough and are misunderstood. In this case, I thought I >> understood until I saw what Tom wrote! LOL! >> I will add this. Is it guaranteed that no two items in the same row are >> never equal or is there some requirement for how to handle a tie? And note >> there are base R functions called min() and max() and you can ask for >> things like: >> >> if ( current == min(mydata[1,])) ... >> >> >> -----Original Message----- >> From: Tom Woolman <twool...@ontargettek.com> >> To: Janet Choate <jsc....@gmail.com> >> Cc: r-help@r-project.org >> Sent: Sun, May 29, 2022 3:42 pm >> Subject: Re: [R] categorizing data >> >> >> Some ideas: >> >> You could create a cluster model with k=3 for each of the 3 variables, >> to determine what constitutes high/medium/low centroid values for each >> of the 3 types of plant types. Centroid values could then be used as the >> upper/lower boundary ranges for high/med/low. >> >> Or utilize a histogram for each variable, and use quantiles or >> densities, etc. to determine the natural breaks for the high/med/low >> ranges for each of the IVs. >> >> >> >> >> On 2022-05-29 15:28, Janet Choate wrote: >>> Hi R community, >>> I have a data frame with three variables, where each row adds up to 90. >>> I want to assign a category of low, medium, or high to the values in >>> each >>> row - where the lowest value per row will be set to 10, the medium >>> value >>> set to 30, and the high value set to 50 - so each row still adds up to >>> 90. >>> >>> For example: >>> Data: Orig >>> tree shrub grass >>> 32 11 47 >>> 23 41 26 >>> 49 23 18 >>> >>> Data: New >>> tree shrub grass >>> 30 10 50 >>> 10 50 30 >>> 50 30 10 >>> >>> I am not attaching any code here as I have not been able to write >>> anything >>> effective! appreciate help with this! >>> thank you, >>> JC >>> >>> -- >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>> 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@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. >> > > > -- > Tague Team Lab Manager > 1005 Bren Hall > UCSB, Santa Barbara, CA. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ********************** "The contents of this message do not reflect any position of the U.S. Government or NOAA." ********************** Roy Mendelssohn Supervisory Operations Research Analyst NOAA/NMFS Environmental Research Division Southwest Fisheries Science Center ***Note new street address*** 110 McAllister Way Santa Cruz, CA 95060 Phone: (831)-420-3666 Fax: (831) 420-3980 e-mail: roy.mendelss...@noaa.gov www: https://www.pfeg.noaa.gov/ "Old age and treachery will overcome youth and skill." 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