Here's a simple example that might be instructive:
x = 9.7900000001
y = 9.79
x
[1] 9.79
y
[1] 9.79
x == y
[1] FALSE
abs(x - y) < 1e-8
[1] TRUE
all.equal(x,y)
[1] TRUE
And as others have said, FAQ 7.31 .
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spec...@stat.berkeley.edu
On Wed, Oct 6, 2010 at 12:02 PM, D. Alain <dialva...@yahoo.de> wrote:
Hi experts,
I have encountered a strange phenomenon after loading spreadsheet data via
example<-read.csv("M:\\...\\mydata.csv",header=T)
My data consist of two variables x and y which I have combined to a single
vector using
z<-rowSums(cbind(example$x,example$y))
z
[1] 9.79 9.79 17.54 12.59 2.18 9.79 #vector z with 6 elements
Now I want to identify all elements equal to 9.79, so I enter
which(z==9.79)
And I get the result
[1] 2 6 #R
failes to identify the fist element!
Taking a futher look at the elements I get the following:
mode(z)
[1] "numeric"
mode(z[1])
[1] "numeric"
z[1]+z[2] #I can
add first and second element
[1] 19.58
But if I try to apply logical operators I get:
z[1]==9.79
[1] FALSE
z[2]==9.79
[1] TRUE
z[1]==z[2]
[1] FALSE
When I reenter the first element via
z[1]<-9.79
z[1]==9.79
[1] TRUE
What is wrong with my data? Can anyone help?
version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 11.1
year 2010
month 05
day 31
svn rev 52157
language R
version.string R version 2.11.1 (2010-05-31)
Thanks
D. Alain
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
______________________________________________
R-help@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@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.
