[R] Interquartile Range

Bert Gunter bgunter.4567 at gmail.com
Wed Apr 20 02:07:47 CEST 2016


Well, instead of your functions try:

Mode <- function(x) {
     tabx <- table(x)
     tabx[which.max(tabx)]
}

and use R's IQR function instead of yours.

... so I still don't get why you want to return a character string
instead of a value for the IQR;
and the mode of a sample defined as above is generally a bad estimator
of the mode of the distribution. To say more than that would take me
too far afield. Post on stats.stackexchange.com if you want to know
why (if it's even relevant).

Cheers,
Bert
Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Tue, Apr 19, 2016 at 4:25 PM, Michael Artz <michaeleartz at gmail.com> wrote:
> Hi,
>   Here is what I am doing
>
> notGroupedAll <- ddply(data
>                  ,~groupColumn
>                  ,summarise
>                  ,col1_mean=mean(col1)
>                  ,col2_mode=Mode(col2) #Function I wrote for getting the
> mode shown below
>                  ,col3_Range=myIqr(col3)
>                  )
>
> groupedAll <- ddply(data
>                  ,~groupColumn
>                  ,summarise
>                  ,col1_mean=mean(col1)
>                  ,col2_mode=Mode(col2) #Function I wrote for getting the
> mode shown below
>                  ,col3_Range=Mode(col3)
>                  )
>
> #custom Mode function
> Mode <- function(x) {
>   ux <- unique(x)
>   ux[which.max(tabulate(match(x, ux)))]
>
> #the range function
> myIqr <- function(x) {
>   paste(round(quantile(x,0.375),0),round(quantile(x,0.625),0),sep="-")
> }
>
>
> }
>
>
> Here is what I am doing!! :)
>
>
>
> On Tue, Apr 19, 2016 at 2:57 PM, William Dunlap <wdunlap at tibco.com> wrote:
>>
>> If you show us, not just tell us about, a self-contained example
>> someone might show you a non-hacky way of getting the job done.
>> (I don't see an argument to plyr::ddply called 'transform'.)
>>
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>> On Tue, Apr 19, 2016 at 12:18 PM, Michael Artz <michaeleartz at gmail.com>
>> wrote:
>>>
>>> Oh thanks for that clarification Bert!  Hope you enjoyed your coffee!  I
>>> ended up just using the transform argument in the ddply function.  It worked
>>> and it repeated, then I called a mode function in another call to ddply that
>>> summarised.  Kinda hacky but oh well!
>>>
>>> On Tue, Apr 19, 2016 at 12:31 PM, Bert Gunter <bgunter.4567 at gmail.com>
>>> wrote:
>>>>
>>>> ... and I'm getting another cup of coffee...
>>>>
>>>> -- Bert
>>>> Bert Gunter
>>>>
>>>> "The trouble with having an open mind is that people keep coming along
>>>> and sticking things into it."
>>>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>>>
>>>>
>>>> On Tue, Apr 19, 2016 at 10:30 AM, Bert Gunter <bgunter.4567 at gmail.com>
>>>> wrote:
>>>> > NO NO  -- I am wrong! The paste() expression is of course evaluated.
>>>> > It's just that a character string is returned of the form "something -
>>>> > something".
>>>> >
>>>> > I apologize for the confusion.
>>>> >
>>>> > -- Bert
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > Bert Gunter
>>>> >
>>>> > "The trouble with having an open mind is that people keep coming along
>>>> > and sticking things into it."
>>>> > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>>> >
>>>> >
>>>> > On Tue, Apr 19, 2016 at 10:25 AM, Bert Gunter <bgunter.4567 at gmail.com>
>>>> > wrote:
>>>> >> To be precise:
>>>> >>
>>>> >> paste(round(quantile(x,0.25),0),round(quantile(x,0.75),0),sep="-")
>>>> >>
>>>> >> is an expression that evaluates to a character string:
>>>> >> "round(quantile(x,.25),0) - round(quantile(x,0.75),0)"
>>>> >>
>>>> >> no matter what the argument of your function, x. Hence
>>>> >>
>>>> >> return(paste(...)) will return this exact character string and never
>>>> >> evaluates x.
>>>> >>
>>>> >>
>>>> >> Cheers,
>>>> >> Bert
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >> Bert Gunter
>>>> >>
>>>> >> "The trouble with having an open mind is that people keep coming
>>>> >> along
>>>> >> and sticking things into it."
>>>> >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>>> >>
>>>> >>
>>>> >> On Tue, Apr 19, 2016 at 8:34 AM, William Dunlap via R-help
>>>> >> <r-help at r-project.org> wrote:
>>>> >>>> That didn't work Jim!
>>>> >>>
>>>> >>> It always helps to say how the suggestion did not work.  Jim's
>>>> >>> function had a typo in it - was that the problem?  Or did you not
>>>> >>> change the call to ddply to use that function.  Here is something
>>>> >>> that might "work" for you:
>>>> >>>
>>>> >>>  library(plyr)
>>>> >>>
>>>> >>>  data <- data.frame(groupColumn=rep(1:5,1:5), col1=2^(0:14))
>>>> >>>  myIqr <- function(x) {
>>>> >>>
>>>> >>> paste(round(quantile(x,0.25),0),round(quantile(x,0.75),0),sep="-")
>>>> >>>  }
>>>> >>>  ddply(data, ~groupColumn, summarise, col1_myIqr=myIqr(col1),
>>>> >>> col1_IQR=stats::IQR(col1))
>>>> >>>  #  groupColumn col1_myIqr col1_IQR
>>>> >>>  #1           1        1-1        0
>>>> >>>  #2           2        2-4        1
>>>> >>>  #3           3      12-24       12
>>>> >>>  #4           4    112-320      208
>>>> >>>  #5           5  2048-8192     6144
>>>> >>>
>>>> >>> The important point is that
>>>> >>>
>>>> >>> paste(round(quantile(x,0.25),0),round(quantile(x,0.75),0),sep="-")
>>>> >>> is not a function, it is an expression.   ddplyr wants functions.
>>>> >>>
>>>> >>>
>>>> >>> Bill Dunlap
>>>> >>> TIBCO Software
>>>> >>> wdunlap tibco.com
>>>> >>>
>>>> >>> On Tue, Apr 19, 2016 at 7:56 AM, Michael Artz
>>>> >>> <michaeleartz at gmail.com>
>>>> >>> wrote:
>>>> >>>
>>>> >>>> That didn't work Jim!
>>>> >>>>
>>>> >>>> Thanks anyway
>>>> >>>>
>>>> >>>> On Mon, Apr 18, 2016 at 9:02 PM, Jim Lemon <drjimlemon at gmail.com>
>>>> >>>> wrote:
>>>> >>>>
>>>> >>>> > Hi Michael,
>>>> >>>> > At a guess, try this:
>>>> >>>> >
>>>> >>>> > iqr<-function(x) {
>>>> >>>> >
>>>> >>>>
>>>> >>>> return(paste(round(quantile(x,0.25),0),round(quantile(x,0.75),0),sep="-")
>>>> >>>> > }
>>>> >>>> >
>>>> >>>> > .col3_Range=iqr(datat$tenure)
>>>> >>>> >
>>>> >>>> > Jim
>>>> >>>> >
>>>> >>>> >
>>>> >>>> >
>>>> >>>> > On Tue, Apr 19, 2016 at 11:15 AM, Michael Artz
>>>> >>>> > <michaeleartz at gmail.com>
>>>> >>>> > wrote:
>>>> >>>> > > Hi,
>>>> >>>> > >   I am trying to show an interquartile range while grouping
>>>> >>>> > > values
>>>> >>>> using
>>>> >>>> > > the function ddply().  So my function call now is like
>>>> >>>> > >
>>>> >>>> > > groupedAll <- ddply(data
>>>> >>>> > >                  ,~groupColumn
>>>> >>>> > >                  ,summarise
>>>> >>>> > >                  ,col1_mean=mean(col1)
>>>> >>>> > >                  ,col2_mode=Mode(col2) #Function I wrote for
>>>> >>>> > > getting
>>>> >>>> the
>>>> >>>> > > mode shown below
>>>> >>>> > >
>>>> >>>> > >
>>>> >>>> > > ,col3_Range=paste(as.character(round(quantile(datat$tenure,c(.25)))),
>>>> >>>> > > as.character(round(quantile(data$tenure,c(.75)))), sep = "-")
>>>> >>>> > >                  )
>>>> >>>> > >
>>>> >>>> > > #custom Mode function
>>>> >>>> > > Mode <- function(x) {
>>>> >>>> > >   ux <- unique(x)
>>>> >>>> > >   ux[which.max(tabulate(match(x, ux)))]
>>>> >>>> > > }
>>>> >>>> > >
>>>> >>>> > > I am not sre what is going wrong on my interquartile range
>>>> >>>> > > function, it
>>>> >>>> > > works on its own outside of ddply()
>>>> >>>> > >
>>>> >>>> > >         [[alternative HTML version deleted]]
>>>> >>>> > >
>>>> >>>> > > ______________________________________________
>>>> >>>> > > R-help at 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 at 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 at 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.
>>>
>>>
>>
>



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