3 messages · Bruno Giovannetti, Benilton Carvalho, Nordlund, Dan (DSHS/RDA)
Hello,
Sometimes the looping (using "for") seems to skip some iterations.
An example:
arg <- matrix(NA,length(seq(.30,.5,.01)),1)
for (i in seq(.30,.5,.01)) {
arg[i*100-29] <- i
}
arg
What is the problem with this coding, please?
Thank you so much,
Bruno Cara Giovannetti, PhD Candidate Economics Department Columbia University Personal Webpage: www.columbia.edu/~bcg2108
it doesn't skip... think about why: seq(.30,.5,.01) * 100 - 29 == 1:21 isn't always TRUE. b
Hello,
Sometimes the looping (using "for") seems to skip some iterations.
An example:
arg <- matrix(NA,length(seq(.30,.5,.01)),1)
for (i in seq(.30,.5,.01)) {
arg[i*100-29] <- i
}
arg
What is the problem with this coding, please?
Thank you so much,
--
Bruno Cara Giovannetti, PhD Candidate
Economics Department
Columbia University
Personal Webpage: www.columbia.edu/~bcg2108
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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Bruno Giovannetti
Sent: Tuesday, November 17, 2009 3:18 PM
To: r-help at r-project.org
Subject: [R] :Problem with Looping
Hello,
Sometimes the looping (using "for") seems to skip some iterations.
An example:
arg <- matrix(NA,length(seq(.30,.5,.01)),1)
for (i in seq(.30,.5,.01)) {
arg[i*100-29] <- i
}
arg
What is the problem with this coding, please?
Thank you so much,
--
Bruno Cara Giovannetti, PhD Candidate
Economics Department
Columbia University
Personal Webpage: www.columbia.edu/~bcg2108
Don't use floating point operations in your indexing. You may also want to change how you generate your sequence. This is a floating point representation problem. See FAQ 7.31. Try something like this
arg <- matrix(NA,length(seq(30,50,1)),1)
for (i in seq(30,50,1)) {arg[i-29] <- i/100 }
Hope this is helpful,
Dan
Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204