[R] Subset

[Boris Steipe]

Always via logical expressions. In this case you can use the logical expression

myDF$b  != "0"

to give you a vector of TRUE/FALSE 



B.


> On Sep 25, 2017, at 8:00 AM, Shane Carey <careyshan at gmail.com> wrote:
> 
> This is super, really helpfull. Sorry, one final question, lets say I wanted to remove 0's rather than NAs , what would it be?
> 
> Thanks
> 
> On Mon, Sep 25, 2017 at 12:41 PM, Boris Steipe <boris.steipe at utoronto.ca> wrote:
> myDF <- data.frame(a = c("<0.1", NA, 0.3, 5, "Nil"),
>                    b = c("<0.1", 1, 0.3, 5, "Nil"),
>                    stringsAsFactors = FALSE)
> 
> # you can subset the b-column in several ways
> 
> myDF[ , 2]
> myDF[ , "b"]
> myDF$b
> 
> # using the column, you make a logical vector
> ! is.na(as.numeric(myDF$b))
> 
> 
> # This can be used to select the rows you want
> 
> myDF[! is.na(as.numeric(myDF$b)), ]
> 
> 
> 
> B.
> 
> 
> > On Sep 25, 2017, at 7:30 AM, Shane Carey <careyshan at gmail.com> wrote:
> >
> > Hi,
> >
> > Lets say this was a dataframe where I had two columns
> >
> > a <- c("<0.1", NA, 0.3, 5, "Nil")
> > b <- c("<0.1", 1, 0.3, 5, "Nil")
> >
> > And I just want to remove the rows from the dataframe where there were NAs in the b column, what is the syntax for doing that?
> >
> > Thanks in advance
> >
> > On Fri, Sep 22, 2017 at 5:04 PM, Shane Carey <careyshan at gmail.com> wrote:
> > Super,
> >
> > Thanks
> >
> > On Fri, Sep 22, 2017 at 4:57 PM, Boris Steipe <boris.steipe at utoronto.ca> wrote:
> > > a <- c("<0.1", NA, 0.3, 5, "Nil")
> > > a
> > [1] "<0.1" NA     "0.3"  "5"    "Nil"
> >
> > > b <- as.numeric(a)
> > Warning message:
> > NAs introduced by coercion
> > > b
> > [1]  NA  NA 0.3 5.0  NA
> >
> > > b[! is.na(b)]
> > [1] 0.3 5.0
> >
> >
> > B.
> >
> >
> > > On Sep 22, 2017, at 11:48 AM, Shane Carey <careyshan at gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > How do I extract just numbers from the following list:
> > >
> > > a=c("<0.1",NA,0.3,5,Nil)
> > >
> > > so I want to obtain: 0.3 and 5 from the above list
> > >
> > > Thanks
> > >
> > >
> > > --
> > > Le gach dea ghui,
> > > *Shane Carey*
> > > *GIS and Data Solutions Consultant*
> > >
> > >       [[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.
> >
> >
> >
> >
> > --
> > Le gach dea ghui,
> > Shane Carey
> > GIS and Data Solutions Consultant
> >
> >
> >
> > --
> > Le gach dea ghui,
> > Shane Carey
> > GIS and Data Solutions Consultant
> 
> 
> 
> 
> -- 
> Le gach dea ghui,
> Shane Carey
> GIS and Data Solutions Consultant