Message-ID: <5372B778-5C50-4C04-81B1-9FAB9BF542FC@comcast.net>
Date: 2016-04-08T03:03:39Z
From: David Winsemius
Subject: why data frame's logical index isnt working
In-Reply-To: <CA+pG8eMq8SauinbLbrUdxn4pkm2MHWhNiUfSR_XAvN4hyQpb6w@mail.gmail.com>
> On Apr 7, 2016, at 7:44 PM, Michael Artz <michaeleartz at gmail.com> wrote:
>
> I don't get it, I thought the double index was to indicate and individual element within a column(vector)?
Character values by themselves either quoted or not are not assumed to refer to column names unless you use `with` or `within`.
> I will stop using data.frame, thanks a lot!
You will have a lot of problems using R if you stop using data.frames.
--
David.
>
> On Thu, Apr 7, 2016 at 9:29 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> > On Apr 7, 2016, at 6:46 PM, Michael Artz <michaeleartz at gmail.com> wrote:
> >
> > data.frame.$columnToAdd["CurrentColumnName" == "ConditionMet"] <- 1
> >
> > Can someone please explain to me why the above command gives all NAs to
> > columnToAdd? I thought this was possible in R to do logical expression in
> > the index of a data frame
>
> It is possible, but please execute this at a console line and then read ?"[" to see what is happening:
>
> "CurrentColumnName" == "ConditionMet" # almost surely FALSE
>
> Let's assume your dataframe were named 'dat'.
>
> Perhaps you meant to write:
>
> dat$colToAdd[ dat[["CurrentColumnName"]] == dat[["ConditionMet"]] ] <- 1
>
> And do please stop naming your dataframes "data.frame".
>
>
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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>
> David Winsemius
> Alameda, CA, USA
>
>
David Winsemius
Alameda, CA, USA