Combining logical operators to extract columns from a dataframe

An embedded and charset-unspecified text was scrubbed...
Name: not available
Url: https://stat.ethz.ch/pipermail/r-help/attachments/20080325/f9065453/attachment.pl
Hi R-helpers,

I have a dataframe (called data) with 100 columns, the columns of which are
named with integers ranging from 1900 to 1999.

I wish to extract those columns which names are >=1950 and <=1970.

I tried:

data2<-subset(data,select=(names(data)>=1950 & names(data)<=1970))

but that doesn't work.

Any ideas?
## untested

data[as.character(1950:1970)]
Thanks! Mark

	[[alternative HTML version deleted]]

______________________________________________
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.
Hi R-helpers,

I have a dataframe (called data) with 100 columns, the columns of which are
named with integers ranging from 1900 to 1999.

I wish to extract those columns which names are >=1950 and <=1970.

I tried:

data2<-subset(data,select=(names(data)>=1950 & names(data)<=1970))

but that doesn't work.

Any ideas?

The subset() function and in particular its select argument is playing 
tricks with the evaluation rules, mostly to be helpful, but sometimes 
apparently not...

Ordinary indexing should work:

data[, names(data) >= "1950" & names(data) <= "1970"]

(using quoted strings to emphasize that you are really comparing 
alphabetically. That is probably OK here, but beware that

 > "999" > 1999
[1] TRUE

Also, BTW, check that names really are "1950", not "X1950" or so. Data 
frame methods like to rationalize column names to be valid variable names.)
Thanks! Mark

	[[alternative HTML version deleted]]

______________________________________________
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.

O__  ---- Peter Dalgaard             ?ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907