[R] NA rows appeared in data.frame

[PIKAL Petr]

Hi

If you want to remove rows with NA values from your data you could use

?complete.cases

or

t2 <- t1[!is.na(t1$Petal.Width),]

Cheers
Petr

> -----Original Message-----
> From: R-help <r-help-bounces using r-project.org> On Behalf Of Rui Barradas
> Sent: Saturday, January 12, 2019 12:55 PM
> To: Ernest Han <ernest.hec using gmail.com>; r-help using r-project.org
> Subject: Re: [R] NA rows appeared in data.frame
>
> Hello,
>
> You have to test for NA. Some (12) of the values of t1$Petal.Width are NA
> therefore t1$Petal.Width == 2.0 alone returns 12 NA values.
>
> t1[t1$Petal.Width == 2.0 & !is.na(t1$Petal.Width == 2.0), ]
>
> Or use which(t1$Petal.Width == 2.0).
>
> t1[which(t1$Petal.Width == 2.0), ]
>
>
> Hope this helps,
>
> Rui Barradas
>
> Às 08:23 de 12/01/2019, Ernest Han escreveu:
> > Dear All,
> >
> > After replacing some values in a data.frame, NAs rows have appeared
> > and cannot be removed. I have googled these issues and found that
> > several people have encountered it. Solutions in stackoverflow seem to
> > provide work-arounds but does not remove it from the data.frame.
> > Therefore, I am turning to experts in this community for help.
> >
> > The code is as follows,
> >
> >> t1 <- iris
> >> t1[t1$Petal.Width==1.8, "Petal.Width"] <- NA t1[t1$Petal.Width ==
> >> 2.0, ]
> >        Sepal.Length Sepal.Width Petal.Length Petal.Width   Species
> > NA              NA          NA           NA          NA      <NA>
> > NA.1            NA          NA           NA          NA      <NA>
> > NA.2            NA          NA           NA          NA      <NA>
> > NA.3            NA          NA           NA          NA      <NA>
> > 111            6.5         3.2          5.1           2 virginica
> > 114            5.7         2.5          5.0           2 virginica
> > NA.4            NA          NA           NA          NA      <NA>
> > 122            5.6         2.8          4.9           2 virginica
> > 123            7.7         2.8          6.7           2 virginica
> > NA.5            NA          NA           NA          NA      <NA>
> > NA.6            NA          NA           NA          NA      <NA>
> > NA.7            NA          NA           NA          NA      <NA>
> > NA.8            NA          NA           NA          NA      <NA>
> > 132            7.9         3.8          6.4           2 virginica
> > NA.9            NA          NA           NA          NA      <NA>
> > NA.10           NA          NA           NA          NA      <NA>
> > 148            6.5         3.0          5.2           2 virginica
> > NA.11           NA          NA           NA          NA      <NA>
> >
> > ## Twelve values were replaced, twelve NA rows appeared.
> >
> > ### MISC INFO ###
> >> sessionInfo()
> > R version 3.4.0 (2017-04-21)
> > Platform: x86_64-apple-darwin16.5.0 (64-bit) Running under: macOS
> > 10.14.2
> >
> > Matrix products: default
> > BLAS:
> > /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/
> > vecLib.framework/Versions/A/libBLAS.dylib
> > LAPACK:
> > /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/
> > vecLib.framework/Versions/A/libLAPACK.dylib
> >
> > locale:
> > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
> >
> > attached base packages:
> > [1] stats     graphics  grDevices utils     datasets  methods   base
> >
> > loaded via a namespace (and not attached):
> > [1] compiler_3.4.0 tools_3.4.0
> >> Sys.getlocale()
> > [1] "en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8"
> >
> >
> > Thank you,
> > Ernest
> >
> > ______________________________________________
> > R-help using 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 using 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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