[R] Hash Table - Select and Change Data iniside Matrix

[Bert Gunter]

Well... (inline)

On Fri, May 25, 2012 at 11:19 AM, arun <smartpink111 at yahoo.com> wrote:
> Hi Antony,
>
> Try this,
> da<-read.table(text="NAME    AGE        PLACE
> ABC        20      INDIA
> XYZ        30      FRANCE
> PQR        40      USA
> MNO        30       KENYA
> DEF        25        AUSTRALIA", header=TRUE,stringsAsFactors=FALSE)
>
>> da2<-function(x){
>  if(x==30)

NO! if is **not** vectorized; this should throw a warning.
>  TRUE
>  else
>  FALSE
>  }
> da3<-sapply(da$AGE,da2)
> TRUE_FALSE<-da3
> da1<-data.frame(da,TRUE_FALSE)

This is poor R programming practice on several different levels. By
adhering to the R paradigm of vectorization, it can be made way
simpler and more transparent. Also note that "TRUE/FALSE" is
potentially problematic as a column name; try to adhere to standard R
names to avoid "infelicities."

Anyway, simply:

da$newColumn <- da$AGE ==30

or, alternatively,

da$newColumn <- with(da, AGE == 30)

Cheers,
Bert


>  da1
>   NAME AGE     PLACE TRUE_FALSE
> 1  ABC  20     INDIA      FALSE
> 2  XYZ  30    FRANCE       TRUE
> 3  PQR  40       USA      FALSE
> 4  MNO  30     KENYA       TRUE
> 5  DEF  25 AUSTRALIA      FALSE
>
>
> A.K.
>
>
>
>
>
>
> ----- Original Message -----
> From: Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
> To: Rantony <antony.akkara at ge.com>; r-help at r-project.org
> Cc:
> Sent: Friday, May 25, 2012 10:25 AM
> Subject: Re: [R] Hash Table - Select and Change Data iniside Matrix
>
> Read help for the ifelse function. Type ?ifelse at the command line.
> ---------------------------------------------------------------------------
> Jeff Newmiller                        The     .....       .....  Go Live...
> DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
>                                       Live:   OO#.. Dead: OO#..  Playing
> Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
> /Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
> ---------------------------------------------------------------------------
> Sent from my phone. Please excuse my brevity.
>
> Rantony <antony.akkara at ge.com> wrote:
>
>>Hi,
>>
>>Here i have been a matrix like this,
>>
>>*NAME    AGE   PALCE                TRUE/FALSE*
>>ABC         20      INDIA
>>XYZ         30       FRANCE
>>PQR        40       USA
>>MNO     30        KENIYA
>>DEF        25        AUSTRALIA
>>
>>Here,* TRUE/FALSE*  Column containing empty values.
>>
>>So my requirement what is , need to change all the *TRUE/FALSE *column
>>value
>>into "*TRUE*" where *AGE = 30*.
>>Note :- i *dont want* to use* any loop *and do. Main intension is avoid
>>loop,bcz there is a bulk of data.
>>
>>Final Matrix should be like this
>>*NAME    AGE   PALCE                TRUE/FALSE*
>>ABC         20      INDIA
>>
>>XYZ         30       FRANCE                     TRUE
>>PQR        40       USA
>>
>>MNO     30        KENIYA                      TRUE
>>DEF        25        AUSTRALIA
>>
>>
>>Immediate Help Requied.
>>
>>Your,
>>Antony.
>>
>>
>>--
>>View this message in context:
>>http://r.789695.n4.nabble.com/Hash-Table-Select-and-Change-Data-iniside-Matrix-tp4631312.html
>>Sent from the R help mailing list archive at Nabble.com.
>>
>>______________________________________________
>>R-help at r-project.org mailing list
>>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 at r-project.org mailing list
> 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 at r-project.org mailing list
> 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.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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