Count unchanged class attribute

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

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