6 messages · Richard Cotton, Gabor Grothendieck, Raubertas, Richard +2 more
In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 NA
b <- factor("a")
c(b, NA)
[1] 1 NA
length(b) <- 2 b
[1] a <NA> Levels: a Hadley
In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 NA
b <- factor("a")
c(b, NA)
[1] 1 NA
length(b) <- 2 b
[1] a <NA> Levels: a
You can save the attributes to a new variable, increase the length, then
reapply the attributes, e.g.
extend <- function(x, n)
{
att <- attributes(x)
length(x) <- n
attributes(x) <- att
x
}
a <- as.Date("2008-01-01")
extend(a, 2)
# [1] "2008-01-01" NA
b <- factor("a")
extend(b, 2)
# [1] a <NA>
# Levels: a
It would, perhaps, be nicer if length had an option to preserve
attributes.
Regards,
Richie.
Mathematical Sciences Unit
HSL
------------------------------------------------------------------------
ATTENTION:
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This may not be everything you would like but perhaps its sufficient:
structure("length<-"(a, 2), class = class(a))
[1] "2008-01-01" NA Your second example looks ok as is. Can't tell what you don't like about it.
In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 ? ?NA
b <- factor("a")
c(b, NA)
[1] ?1 NA
length(b) <- 2 b
[1] a ? ?<NA> Levels: a Hadley -- http://had.co.nz/
______________________________________________ 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.
The following approach works for both of your examples: xx <- rep(x, length.out=n) xx[m:n] <- NA Thus:
n <- 2 aa <- rep(a, length.out=n) aa[(length(a)+1):n] <- NA aa
[1] "2008-01-01" NA
bb <- rep(b, length.out=n) bb[(length(b)+1):n] <- NA bb
[1] a <NA> Levels: a
R. Raubertas Merck & Co
-----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of hadley wickham Sent: Wednesday, April 15, 2009 10:55 AM To: r-help Subject: [R] Extending a vector to length n In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 NA
b <- factor("a")
c(b, NA)
[1] 1 NA
length(b) <- 2 b
[1] a <NA> Levels: a Hadley -- http://had.co.nz/
______________________________________________ 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.
Notice: This e-mail message, together with any attachme...{{dropped:12}}
Great idea - that's a little faster than my previous approach of setting length() and then re-adding the attributes. Thanks! Hadley On Thu, Apr 16, 2009 at 12:16 PM, Raubertas, Richard
The following approach works for both of your examples: xx <- rep(x, length.out=n) xx[m:n] <- NA Thus:
n <- 2 aa <- rep(a, length.out=n) aa[(length(a)+1):n] <- NA aa
[1] "2008-01-01" NA
bb <- rep(b, length.out=n) bb[(length(b)+1):n] <- NA bb
[1] a ? ?<NA> Levels: a
R. Raubertas Merck & Co
-----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of hadley wickham Sent: Wednesday, April 15, 2009 10:55 AM To: r-help Subject: [R] Extending a vector to length n In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 ? ?NA
b <- factor("a")
c(b, NA)
[1] ?1 NA
length(b) <- 2 b
[1] a ? ?<NA> Levels: a Hadley -- http://had.co.nz/
______________________________________________ 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.
Notice: ?This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu - direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system.
Folks: Not to be picky, but depending on exactly what's meant by "attributes," I think it's impossible:
x <- 1:6 attr(x,"length") <- length(x) xx <- rep(x,length=10) xx[7:10] <- NA attr(xx,"length")
NULL
attr(x,"length")
[1] 6 So "attributes" aren't preserved. The whole point of object orientation and method dispatch is to deal with this issue in a coherent way. Cheers, Bert -----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of hadley wickham Sent: Thursday, April 16, 2009 10:50 AM To: Raubertas, Richard Cc: r-help Subject: Re: [R] Extending a vector to length n Great idea - that's a little faster than my previous approach of setting length() and then re-adding the attributes. Thanks! Hadley On Thu, Apr 16, 2009 at 12:16 PM, Raubertas, Richard
The following approach works for both of your examples: xx <- rep(x, length.out=n) xx[m:n] <- NA Thus:
n <- 2 aa <- rep(a, length.out=n) aa[(length(a)+1):n] <- NA aa
[1] "2008-01-01" NA
bb <- rep(b, length.out=n) bb[(length(b)+1):n] <- NA bb
[1] a ? ?<NA> Levels: a
R. Raubertas Merck & Co
-----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of hadley wickham Sent: Wednesday, April 15, 2009 10:55 AM To: r-help Subject: [R] Extending a vector to length n In general, how can I increase a vector of length m (< n) to length n by padding it with m - n missing values, without losing attributes? The two approaches I've tried, using length<- and adding missings with c, do not work in general:
a <- as.Date("2008-01-01")
c(a, NA)
[1] "2008-01-01" NA
length(a) <- 2 a
[1] 13879 ? ?NA
b <- factor("a")
c(b, NA)
[1] ?1 NA
length(b) <- 2 b
[1] a ? ?<NA> Levels: a Hadley -- http://had.co.nz/
______________________________________________ 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.
Notice: ?This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu - direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system.
http://had.co.nz/ ______________________________________________ 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.