[R] Count unchanged class attribute

[Jim Lemon]

Hi Xiyan,
I have to admit that your puzzle very nearly stumped me. At first I
thought the question was:

"What are the numbers of rows with changed and unchanged class values?"

That doesn't work as there are at most four rows and your answer sums
to five. I then tried:

"How many times does at least one value of class change between
successive data frames?"

Nope, four have at least one change. Could it have been:

"Using unique combinations of the values of Netto and Bruto, how many
changes have occurred?"

Wrong again, there are 12 combinations, not five. Surely you don't mean:

"In how many data frames does ta least one value of class equal 'no'?"

df1<-data.frame(Netto=c(10,100),Bruto=c(1000,20),class=c("yes","yes"))
df2<-data.frame(Netto=c(101,100),Bruto=c(1000,210),class=c("yes","no"))
df3<-data.frame(Netto=c(10,12,100),Bruto=c(10,28,20),class=c("yes","yes","yes"))
df4<-data.frame(Netto=c(120,400),Bruto=c(200,20),class=c("no","yes"))
df5<-data.frame(Netto=c(110,1100,120,1140),Bruto=c(12000,120,100,125),
 class=c("yes","yes","yes","yes"))
sxdat<-list(df1,df2,df3,df4,df5)
table(ifelse(unlist(lapply(sxdat,function(x)
return(any(x$class=="no")))),"changed","unchanged"))

Jim

On Wed, May 20, 2015 at 1:04 PM, Bert Gunter <gunter.berton at gene.com> wrote:
> Probably "or what."
>
> This demonstrates a fundamental conundrum: many users or prospective users
> of R have had little exposure to data structures in their formal education
> and therefore can be flummoxed by R's fussiness -- as any programming
> language must necessarily be. Consider: data frames, matrices, lists,
> "classes", objects with attributes (e.g. factors),...
>
> Excel, which is basically structureless, of course, exacerbates the
> problem. Those accustomed to its tolerance (and the confusion that results)
> expect R to behave the same way. Education is the only recourse, either in
> formal courses or through R tutorials that strongly emphasize this aspect
> of interacting with R and especially writing effective code. But that
> demands effort and, to some extent, aptitude... both of which seem to be in
> increasingly short supply amidst the worldwide explosion in R's usage.
>
> Of course, feel free to disagree... Just my $.02
>
> Cheers,
> Bert
>
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
> (650) 467-7374
>
> "Data is not information. Information is not knowledge. And knowledge is
> certainly not wisdom."
> Clifford Stoll
>
>
>
> On Tue, May 19, 2015 at 7:02 PM, John Kane <jrkrideau at inbox.com> wrote:
>
>> Is this a list of data.frames or what?
>>
>> Please have a look at one or both of these for some ideas of how to ask a
>> question and provide information on the problem.  The better you can
>> describe what you have and what you need the better people can help.
>>
>> http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
>> and http://adv-r.had.co.nz/Reproducibility.html
>>
>>
>> John Kane
>> Kingston ON Canada
>>
>>
>> > -----Original Message-----
>> > From: soe.xiyan at gmail.com
>> > Sent: Tue, 19 May 2015 23:37:13 +0700
>> > To: r-help at r-project.org
>> > Subject: [R] Count unchanged class attribute
>> >
>> > Maybe someone can help me.
>> > Suppose I have data-set like this:
>> >
>> >   Netto   Bruto  class
>> > 1 10      1000    yes
>> > 2 100     20      yes
>> >
>> >
>> >   Netto   Bruto  class
>> > 1 101     1000    yes
>> > 2 100     210     no
>> >
>> >
>> >   Netto   Bruto  class
>> > 1 10      10      yes
>> > 2 12      28      yes
>> > 3 100     20      yes
>> >
>> >   Netto   Bruto  class
>> > 1 120     200     no
>> > 2 400     20      yes
>> >
>> >
>> >   Netto   Bruto  class
>> > 1 110     12000   yes
>> > 2 1100    120     yes
>> > 3 120     100     yes
>> > 4 1140    125     yes
>> >
>> > How to calculate the number of classes has changed.
>> > The expected result is
>> > - class changed    2
>> > - class unchanged  3
>> >
>> >
>> > Thank you so much.
>> > Soe Xiyan
>> >
>> >       [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
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>> > 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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>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>> 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.