[R] why data frame's logical index isnt working

[David Winsemius]

> 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".
> 
> 
> >
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> >
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> 
> David Winsemius
> Alameda, CA, USA
> 
> 

David Winsemius
Alameda, CA, USA