Chris Evans
2016-Nov-27 15:12 UTC
[R] In praise of "options(warnPartialMatchDollar = TRUE)"
I am just posting this to the list because someone else may one day waste an
hour or so because s/he has unknowingly hit a partial match failure using
"$". It's my folly that I did but I am surprised that
options(warnPartialMatchDollar = TRUE) isn't the default setting.
Here's a bit of reproducible code that shows the challenge.
#rm(list=ls()) ### BEWARE: me making sure environment was clean
set.seed(12345) # get fully reproducible example
nRows <- 100
Sample <- sample(0:1,nRows,replace=TRUE)
data2 <- data.frame(cbind(1:nRows,Sample)) # create data frame
table(data2$Samp) # call which silently achieves partial match
data2$innoccuousname <-
factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1)
str(data2$Samp) # all fine, no apparent destruction of the non-existent vector
data2$Samp
data2$SampFac <-
factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1)
str(data2$Samp) # returns NULL because there is no longer a single partial match
to "Samp" but no warning!
str(data2$Sample) # but of course, data2$Sample is still there
Because I had used "data2$Samp" all the way through a large file of R
(markup) code and hadn't noticed that the variable names in the SPSS file I
was reading in had changed from "Samp" to "Sample" I
appeared to be destroying data2$Samp.
I have now set options(warnPartialMatchDollar = TRUE) in my Rprofile.site file
and am just posting this here in case it helps someone some day.
Very best all,
Chris
[[alternative HTML version deleted]]
David Winsemius
2016-Nov-27 18:25 UTC
[R] In praise of "options(warnPartialMatchDollar = TRUE)"
> On Nov 27, 2016, at 7:12 AM, Chris Evans <chrishold at psyctc.org> wrote: > > I am just posting this to the list because someone else may one day waste an hour or so because s/he has unknowingly hit a partial match failure using "$". It's my folly that I did but I am surprised that options(warnPartialMatchDollar = TRUE) isn't the default setting. > > Here's a bit of reproducible code that shows the challenge. > > #rm(list=ls()) ### BEWARE: me making sure environment was clean > set.seed(12345) # get fully reproducible example > nRows <- 100 > Sample <- sample(0:1,nRows,replace=TRUE) > data2 <- data.frame(cbind(1:nRows,Sample)) # create data frameUsing dataframe( cbind( ...) ) is a predictable method for creating later headaches. and there is no options-warning available. cbind coerces an argument list of vectors to matrix class, thus dropping all attributes (dates, times and factors are all destroyed.)> table(data2$Samp) # call which silently achieves partial match > data2$innoccuousname <- factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1) > str(data2$Samp) # all fine, no apparent destruction of the non-existent vector data2$Samp > data2$SampFac <- factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1) > str(data2$Samp) # returns NULL because there is no longer a single partial match to "Samp" but no warning! > str(data2$Sample) # but of course, data2$Sample is still there > > Because I had used "data2$Samp" all the way through a large file of R (markup) code and hadn't noticed that the variable names in the SPSS file I was reading in had changed from "Samp" to "Sample" I appeared to be destroying data2$Samp. > > I have now set options(warnPartialMatchDollar = TRUE) in my Rprofile.site file and am just posting this here in case it helps someone some day.This is one of the reasons many experienced R programmers eschew the use of the "$" function in programming. The preferred use would be : data2[['Samp']] (No partial match.)> > [[alternative HTML version deleted]]Plain text is generally preferred on Rhelp but there does not appear to have been a problem in this posting instance.> > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.David Winsemius Alameda, CA, USA
Chris Evans
2016-Nov-27 19:21 UTC
[R] In praise of "options(warnPartialMatchDollar = TRUE)"
Was about to reply just to sender but thought there were good byproducts of this so, to all ... Many thanks Dr. Winsemius, and apologies for the HTML: tired sloppiness. My bad. Aha. For the first time I can really see a logic for dataFrame[['variable']] -- thanks for that. I will have to break myself of the "$" habit. Pity as it's a lot more keystrokes! W I understand about the nasty asset stripped side effects of cbind but thought in this situation it would cause no problems. Is the preferred route to create turn a first vector to data frame and then add the others using dataframe[['newVariable']] <- nextVector ? Very best wishes and thanks again: this is an amazing list, Chris ----- Original Message -----> From: "David Winsemius" <dwinsemius at comcast.net> > To: "Chris Evans" <chrishold at psyctc.org> > Cc: r-help at r-project.org > Sent: Sunday, 27 November, 2016 18:25:18 > Subject: Re: [R] In praise of "options(warnPartialMatchDollar = TRUE)">> On Nov 27, 2016, at 7:12 AM, Chris Evans <chrishold at psyctc.org> wrote: >> >> I am just posting this to the list because someone else may one day waste an >> hour or so because s/he has unknowingly hit a partial match failure using "$". >> It's my folly that I did but I am surprised that options(warnPartialMatchDollar >> = TRUE) isn't the default setting. >> >> Here's a bit of reproducible code that shows the challenge. >> >> #rm(list=ls()) ### BEWARE: me making sure environment was clean >> set.seed(12345) # get fully reproducible example >> nRows <- 100 >> Sample <- sample(0:1,nRows,replace=TRUE) >> data2 <- data.frame(cbind(1:nRows,Sample)) # create data frame > > Using dataframe( cbind( ...) ) is a predictable method for creating later > headaches. and there is no options-warning available. cbind coerces an argument > list of vectors to matrix class, thus dropping all attributes (dates, times and > factors are all destroyed.) > >> table(data2$Samp) # call which silently achieves partial match >> data2$innoccuousname <- >> factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1) >> str(data2$Samp) # all fine, no apparent destruction of the non-existent vector >> data2$Samp >> data2$SampFac <- >> factor(data2$Samp,labels=c("Non-clinical","Clinical"),levels=0:1) >> str(data2$Samp) # returns NULL because there is no longer a single partial match >> to "Samp" but no warning! >> str(data2$Sample) # but of course, data2$Sample is still there >> >> Because I had used "data2$Samp" all the way through a large file of R (markup) >> code and hadn't noticed that the variable names in the SPSS file I was reading >> in had changed from "Samp" to "Sample" I appeared to be destroying data2$Samp. >> >> I have now set options(warnPartialMatchDollar = TRUE) in my Rprofile.site file >> and am just posting this here in case it helps someone some day. > > This is one of the reasons many experienced R programmers eschew the use of the > "$" function in programming. > > The preferred use would be : > > data2[['Samp']] > > (No partial match.) > >> >> [[alternative HTML version deleted]] > > Plain text is generally preferred on Rhelp but there does not appear to have > been a problem in this posting instance. > >> >> ______________________________________________ >> 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. > > David Winsemius > Alameda, CA, USA