[R] how to test the existence of a name in a dataframe

Dimitris Rizopoulos dimitris.rizopoulos at med.kuleuven.ac.be
Tue Dec 7 10:06:45 CET 2004

Hi Wolfram,

this behaviour is due to partial matching. Observe that


I think the best way to do it is with `%in%' or `match()', i.e.,

c("Ed", "Edu", "Educ", "Education") %in% names(swiss)

I hope it helps.


Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat

----- Original Message ----- 
From: "Wolfram Fischer" <wolfram at fischer-zim.ch>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, December 07, 2004 9:47 AM
Subject: [R] how to test the existence of a name in a dataframe

>I wanted to test if there exists already a name (which is
> incidentally a substring of another name) in a dataframe.
> I did e.g.:
>> data(swiss)
>> names(swiss)
> [1] "Fertility"        "Agriculture"      "Examination" 
> "Education"
> [5] "Catholic"         "Infant.Mortality"
>> ! is.null(swiss$EduX)
> [1] FALSE
>> ! is.null(swiss$Edu)
> [1] TRUE
> I did not expect to get TRUE here because ``Edu'' does not exist
> as name of ``swiss''.
> I did finally:
>> 'Edu' %in% names(swiss)
> for which I got the expected FALSE.
> My question: What is the recommended way to do such a test?
> Thanks - Wolfram Fischer
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