[R] Subscripting problem with is.na()
PIKAL Petr
petr.pikal at precheza.cz
Fri Jun 24 11:19:38 CEST 2016
Hi
I do not consider changing NA to 0 as a reasonable approach ( maybe only in some special case, which is not yours).
rowSums(is.na(ds_temp1[,2:3]))
[1] 1 1 2 2 0 0 2 2 1 2 1 2 1 2 1 2 2 2 2 2
gives you vector of numbers which is equal 2 only if they are both NA. So
ds_temp1$open <- rowSums(is.na(ds_temp1[,2:3]))==2
gives you column which is TRUE if the account is open and FALSE in other situation.
You can use similar approach for testing the state of account closing.
Cheers
Petr
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of
> G.Maubach at gmx.de
> Sent: Friday, June 24, 2016 9:15 AM
> To: Bert Gunter <bgunter.4567 at gmail.com>
> Cc: R Help <r-help at r-project.org>
> Subject: Re: [R] Subscripting problem with is.na()
>
> Hi Bert,
>
> many thanks for all your help and your comments. I learn at lot this way.
>
> My question was about is.na() at the first sight but the actual task looks like
> this:
>
> I have two variables in my customer data that signal if the customer accout
> was closed by master data management or by sales. Say these variables are
> closed_mdm and closed_sls. They contain NA if the customer account is still
> open or a closing code from "01" to "08" if the customer account was closed
> and why.
>
> For my analysis I need a variable that combines the two variables
> closed_mdm and closed_sls to set a filter easily on those who are closed not
> matter what the reason was nor who closed the account.
>
> As I always encounter problems when dealing with ifelse statements and NA
> I decided to merge these two variables to one variable containing 0 = not
> closed and 1 = closed. In my context this seems to be - at least to me - a
> reasonable approach.
>
> Replacement of missing values and merging the variables is the easiest way
> for me.
>
> -- cut --
>
> cust_id <- c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
> closed_mdm <- c("01", NA, NA, NA, "08", "07", NA, NA, "05", NA, NA, NA,
> "04", NA, NA, NA, NA, NA, NA, NA)
> closed_sls <- c(NA, "08", NA, NA, "08", "07", NA, NA, NA, NA, "03", NA, NA,
> NA, "05", NA, NA, NA, NA, NA)
>
> # 1st try
> ds_temp1 <- data.frame(cust_id, closed_mdm, closed_sls)
> ds_temp1
>
> ds_temp1$closed <- closed_mdm | closed_sls # WRONG
>
> # 2nd try
> closed_mdm_fac1 <- as.factor(closed_mdm)
> closed_sls_fac1 <- as.factor(closed_sls)
>
> ds_temp2 <- data.frame(cust_id, closed_mdm_fac1, closed_sls_fac1)
> ds_temp2
>
> ds_temp2$closed <- ds_temp$closed_mdm_fac1 |
> ds_temp$closed_sls_fac1 # WRONG
>
> # 3rd try
> closed_mdm_num1 <- as.numeric(closed_mdm) # OK
> closed_sls_num1 <- as.numeric(closed_sls) # OK
>
> ds_temp3 <- data.frame(cust_id, closed_mdm_num1, closed_sls_num1)
> ds_temp3
>
> ds_temp3$closed <- ds_temp$closed_mdm_num1 |
> ds_temp$closed_sls_num1 # WRONG
>
> # 4th try
> ds_temp4 <- ds_temp3
> ds_temp4
>
> # Does not run due to not allowed NA in subscripts
> ds_temp4[is.na(ds_temp4$closed_mdm_num1),
> ds_temp4$closed_mdm_num1] <- 0
> ds_temp4[is.na(ds_temp4$closed_sls_num1), ds_temp4$closed_sls_num1]
> <- 0
>
> # 5th try
> ds_temp4$closed_mdm_num1 <-
> ifelse(is.na(ds_temp4$closed_mdm_num1), 1, 0)
> ds_temp4$closed_sls_num1 <- ifelse(is.na(ds_temp4$closed_sls_num1), 1,
> 0)
> ds_temp4
>
> ds_temp4$closed <- ifelse(ds_temp4$closed_mdm_num1 == 1 |
> ds_temp4$closed_sls_num1 == 1, 1, 0)
> ds_temp4
>
> -- cut --
>
> Is there a better way to do it?
>
> Kind regards
>
> Georg
>
>
> > Gesendet: Donnerstag, 23. Juni 2016 um 23:55 Uhr
> > Von: "Bert Gunter" <bgunter.4567 at gmail.com>
> > An: "David L Carlson" <dcarlson at tamu.edu>
> > Cc: "R Help" <r-help at r-project.org>
> > Betreff: Re: [R] Subscripting problem with is.na()
> >
> > ... actually, FWIW, I would say that this little discussion mostly
> > demonstrates why the OP's request is probably not a good idea in the
> > first place. Usually, NA's should be left as NA's to be dealt with
> > properly by R and packages. In biological measurements, for example,
> > NA's often mean "below the ability to reliably measure." Biologists
> > with whom I've worked over many years often want to convert these to 0
> > or omit the cases, both of which lead to biased estimates and/or
> > underestimates of variability and excess claims of "statistical
> > significance" (for those who belong to this religious persuasion). One
> > should never say never, but I suspect that there are relatively few
> > circumstances where the conversion the OP requested is actually wise.
> >
> > Feel free to ignore/reject such extraneous comments of course.
> >
> > 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 Thu, Jun 23, 2016 at 12:14 PM, David L Carlson <dcarlson at tamu.edu>
> wrote:
> > > Good point. I did not think about factors. Also your example raises
> another issue since column c is logical, but gets silently converted to numeric.
> This would seem to get the job done assuming the conversion is intended for
> numeric columns only:
> > >
> > >> test <- data.frame(a=c(1,NA,2), b = c("A","b",NA), c= rep(NA,3))
> > >> sapply(test, class)
> > > a b c
> > > "numeric" "factor" "logical"
> > >> num <- sapply(test, is.numeric)
> > >> test[, num][is.na(test[, num])] <- 0
> > >> test
> > > a b c
> > > 1 1 A NA
> > > 2 0 b NA
> > > 3 2 <NA> NA
> > >
> > > David C
> > >
> > > -----Original Message-----
> > > From: Bert Gunter [mailto:bgunter.4567 at gmail.com]
> > > Sent: Thursday, June 23, 2016 1:48 PM
> > > To: David L Carlson
> > > Cc: Ivan Calandra; R Help
> > > Subject: Re: [R] Subscripting problem with is.na()
> > >
> > > Not in general, David:
> > >
> > > e.g.
> > >
> > >> test <- data.frame(a=c(1,NA,2), b = c("A","b",NA), c= rep(NA,3))
> > >
> > >> is.na(test)
> > > a b c
> > > [1,] FALSE FALSE TRUE
> > > [2,] TRUE FALSE TRUE
> > > [3,] FALSE TRUE TRUE
> > >
> > >> test[is.na(test)]
> > > [1] NA NA NA NA NA
> > >
> > >> test[is.na(test)] <- 0
> > > Warning message:
> > > In `[<-.factor`(`*tmp*`, thisvar, value = 0) :
> > > invalid factor level, NA generated
> > >
> > >> test
> > > a b c
> > > 1 1 A 0
> > > 2 0 b 0
> > > 3 2 <NA> 0
> > >
> > >
> > > The problem is the default conversion to factors and the replacement
> > > operation for factors. So:
> > >
> > >> test <- data.frame(a=c(1,NA,2), b = I(c("A","b",NA_character_)), c=
> rep(NA,3))
> > >> class(test$b)
> > > [1] "AsIs" ## so NOT a factor
> > >
> > >> test[is.na(test)] <- 0 # now works as you describe
> > >> test
> > > a b c
> > > 1 1 A 0
> > > 2 0 b 0
> > > 3 2 0 0
> > >
> > > Of course the OP (and you) probably had a data frame of all numerics
> > > in mind, so the problem doesn't arise. But I think one needs to make
> > > the distinction and issue clear.
> > >
> > > 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 Thu, Jun 23, 2016 at 8:46 AM, David L Carlson <dcarlson at tamu.edu>
> wrote:
> > >> The function is.na() returns a matrix when applied to a data.frame so
> you can easily convert all the NAs to 0's:
> > >>
> > >>> ds_test
> > >> var1 var2
> > >> 1 1 1
> > >> 2 2 2
> > >> 3 3 3
> > >> 4 NA NA
> > >> 5 5 5
> > >> 6 6 6
> > >> 7 7 7
> > >> 8 NA NA
> > >> 9 9 9
> > >> 10 10 10
> > >>> is.na(ds_test)
> > >> var1 var2
> > >> [1,] FALSE FALSE
> > >> [2,] FALSE FALSE
> > >> [3,] FALSE FALSE
> > >> [4,] TRUE TRUE
> > >> [5,] FALSE FALSE
> > >> [6,] FALSE FALSE
> > >> [7,] FALSE FALSE
> > >> [8,] TRUE TRUE
> > >> [9,] FALSE FALSE
> > >> [10,] FALSE FALSE
> > >>> ds_test[is.na(ds_test)] <- 0
> > >>> ds_test
> > >> var1 var2
> > >> 1 1 1
> > >> 2 2 2
> > >> 3 3 3
> > >> 4 0 0
> > >> 5 5 5
> > >> 6 6 6
> > >> 7 7 7
> > >> 8 0 0
> > >> 9 9 9
> > >> 10 10 10
> > >>
> > >> -------------------------------------
> > >> David L Carlson
> > >> Department of Anthropology
> > >> Texas A&M University
> > >> College Station, TX 77840-4352
> > >>
> > >> -----Original Message-----
> > >> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ivan
> Calandra
> > >> Sent: Thursday, June 23, 2016 10:14 AM
> > >> To: R Help
> > >> Subject: Re: [R] Subscripting problem with is.na()
> > >>
> > >> Thank you Bert for this clarification. It is indeed an important point.
> > >>
> > >> Ivan
> > >>
> > >> --
> > >> Ivan Calandra, PhD
> > >> Scientific Mediator
> > >> University of Reims Champagne-Ardenne
> > >> GEGENAA - EA 3795
> > >> CREA - 2 esplanade Roland Garros
> > >> 51100 Reims, France
> > >> +33(0)3 26 77 36 89
> > >> ivan.calandra at univ-reims.fr
> > >> --
> > >> https://www.researchgate.net/profile/Ivan_Calandra
> > >> https://publons.com/author/705639/
> > >>
> > >> Le 23/06/2016 à 17:06, Bert Gunter a écrit :
> > >>> Sorry, Ivan, your statement is incorrect:
> > >>>
> > >>> "When you use a single bracket on a list with only one argument in
> > >>> between, then R extracts "elements", i.e. columns in the case of a
> > >>> data.frame. This explains your errors. "
> > >>>
> > >>> e.g.
> > >>>
> > >>>> ex <- data.frame(a = 1:3, b = letters[1:3])
> > >>>> a <- 1:3
> > >>>> identical(ex[1], a)
> > >>> [1] FALSE
> > >>>
> > >>>> class(ex[1])
> > >>> [1] "data.frame"
> > >>>> class(a)
> > >>> [1] "integer"
> > >>>
> > >>> Compare:
> > >>>
> > >>>> identical(ex[[1]], a)
> > >>> [1] TRUE
> > >>>
> > >>> Why? Single bracket extraction on a list results in a list; double
> > >>> bracket extraction results in the element of the list ( a "column" in
> > >>> the case of a data frame, which is a specific kind of list). The
> > >>> relevant sections of ?Extract are:
> > >>>
> > >>> "Indexing by [ is similar to atomic vectors and selects a **list** of
> > >>> the specified element(s).
> > >>>
> > >>> Both [[ and $ select a **single element of the list**. "
> > >>>
> > >>>
> > >>> Hope this clarifies this often-confused issue.
> > >>>
> > >>>
> > >>> 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 Thu, Jun 23, 2016 at 7:34 AM, Ivan Calandra
> > >>> <ivan.calandra at univ-reims.fr> wrote:
> > >>>> My statement "Using a single bracket '[' on a data.frame does the
> same as
> > >>>> for matrices: you need to specify rows and columns" was not correct.
> > >>>>
> > >>>>
> > >>>> When you use a single bracket on a list with only one argument in
> between,
> > >>>> then R extracts "elements", i.e. columns in the case of a data.frame.
> This
> > >>>> explains your errors.
> > >>>>
> > >>>> But it is possible to use a single bracket on a data.frame with 2
> arguments
> > >>>> (rows, columns) separated by a comma, as with matrices. This is the
> solution
> > >>>> you received.
> > >>>>
> > >>>> Ivan
> > >>>>
> > >>>>
> > >>>> --
> > >>>> Ivan Calandra, PhD
> > >>>> Scientific Mediator
> > >>>> University of Reims Champagne-Ardenne
> > >>>> GEGENAA - EA 3795
> > >>>> CREA - 2 esplanade Roland Garros
> > >>>> 51100 Reims, France
> > >>>> +33(0)3 26 77 36 89
> > >>>> ivan.calandra at univ-reims.fr
> > >>>> --
> > >>>> https://www.researchgate.net/profile/Ivan_Calandra
> > >>>> https://publons.com/author/705639/
> > >>>>
> > >>>> Le 23/06/2016 à 16:27, Ivan Calandra a écrit :
> > >>>>> Dear Georg,
> > >>>>>
> > >>>>> You need to learn a bit more about the subsetting methods,
> depending on
> > >>>>> the object structure you're trying to subset.
> > >>>>>
> > >>>>> More specifically, when you run this: ds_test[is.na(ds_test$var1)]
> > >>>>> you get this error: "Error in `[.data.frame`(ds_test,
> is.na(ds_test$var1))
> > >>>>> : undefined columns selected"
> > >>>>>
> > >>>>> This means that R does not understand which column you're trying
> to
> > >>>>> select. But you're actually trying to select rows.
> > >>>>>
> > >>>>> Using a single bracket '[' on a data.frame does the same as for
> matrices:
> > >>>>> you need to specify rows and columns, like this:
> > >>>>> ds_test[is.na(ds_test$var1), ] ## notice the last comma
> > >>>>> ds_test[is.na(ds_test$var1), ] <- 0 ## works on all columns because
> you
> > >>>>> didn't specify any after the comma
> > >>>>>
> > >>>>> If you want it only for "var1", then you need to specify the column:
> > >>>>> ds_test[is.na(ds_test$var1), "var1"] <- 0
> > >>>>>
> > >>>>> It's the same problem with your 2nd and 4th tries (4th one has other
> > >>>>> problems). Your 3rd try does not change ds_test at all.
> > >>>>>
> > >>>>> HTH,
> > >>>>> Ivan
> > >>>>>
> > >>>>> --
> > >>>>> Ivan Calandra, PhD
> > >>>>> Scientific Mediator
> > >>>>> University of Reims Champagne-Ardenne
> > >>>>> GEGENAA - EA 3795
> > >>>>> CREA - 2 esplanade Roland Garros
> > >>>>> 51100 Reims, France
> > >>>>> +33(0)3 26 77 36 89
> > >>>>> ivan.calandra at univ-reims.fr
> > >>>>> --
> > >>>>> https://www.researchgate.net/profile/Ivan_Calandra
> > >>>>> https://publons.com/author/705639/
> > >>>>>
> > >>>>> Le 23/06/2016 à 15:57, G.Maubach at weinwolf.de a écrit :
> > >>>>>> Hi All,
> > >>>>>>
> > >>>>>> I would like to recode my NAs to 0. Using a single vector everything
> is
> > >>>>>> fine.
> > >>>>>>
> > >>>>>> But if I use a data.frame things go wrong:
> > >>>>>>
> > >>>>>> -- cut --
> > >>>>>>
> > >>>>>> var1 <- c(1:3, NA, 5:7, NA, 9:10)
> > >>>>>> var2 <- c(1:3, NA, 5:7, NA, 9:10)
> > >>>>>> ds_test <-
> > >>>>>> data.frame(var1, var2)
> > >>>>>>
> > >>>>>> test <- var1
> > >>>>>> test[is.na(test)] <- 0
> > >>>>>> test # NA recoded OK
> > >>>>>>
> > >>>>>> # First try
> > >>>>>> ds_test[is.na(ds_test$var1)] <- 0 # duplicate subscripts WRONG
> > >>>>>>
> > >>>>>> # Second try
> > >>>>>> ds_test[is.na("var1")] <- 0
> > >>>>>> ds_test$var1 # not recoded WRONG
> > >>>>>>
> > >>>>>> # Third try: to me the most intuitive approach
> > >>>>>> is.na(ds_test["var1"]) <- 0 # attempt to select less than one
> element in
> > >>>>>> integerOneIndex WRONG
> > >>>>>>
> > >>>>>> # Fourth try
> > >>>>>> ds_test[is.na(var1)] <- 0 # duplicate subscripts for columns
> WRONG
> > >>>>>>
> > >>>>>> -- cut --
> > >>>>>> How can I do it correctly?
> > >>>>>>
> > >>>>>> Where could I have found something about it?
> > >>>>>>
> > >>>>>> Kind regards
> > >>>>>>
> > >>>>>> Georg
> > >>>>>>
> > >>>>>> ______________________________________________
> > >>>>>> 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.
> > >>>>>>
> > >>>>> ______________________________________________
> > >>>>> 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.
> > >>>>>
> > >>>> ______________________________________________
> > >>>> 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.
> > >>
> > >> ______________________________________________
> > >> 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.
> > >> ______________________________________________
> > >> 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.
> >
> > ______________________________________________
> > 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.
>
> ______________________________________________
> 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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