On Sep 16, 2011, at 10:08 AM, B77S wrote:
I'm sure Sarah's solution works (and she knows more about R than
myself), but
I ran into a similar problem and used:
as.character(start.time)==as.character(expected_start.time)
What you did was an implicit rounding of the values to the digits
level specified by some process, possibly a default formatting spec,
guessing to round(num, 7) . I tried to see whether package chron might
specify i,t but this effort only produced this
> cur.opts <- names(options())
> require(chron)
Loading required package: chron
> names(options())[!names(options()) %in% cur.opts]
[1] "chron.year.abb" "chron.year.expand"
What Sarah suggested was essentially rounding to 16 digits to the
right of the decimal.
If the OP had offered dput() on these objects, there would have been
a lot less guessing.
--
David
good luck regardless.
-BS
Sarah Goslee wrote:
Sounds like a case for FAQ 7.31, or, yet another machine precision
issue.
Try all.equal() instead of ==
Sarah
On Fri, Sep 16, 2011 at 7:36 AM, mebstyne <mebst...@me.com>
wrote:
I have two local variables: startTime and expectedStartTime. Both
are
chron
related objects.
When I look at the class for the objects I can see they are of class
"times".
When I print them to the console, they both read: "09:30:00"
When I print them as.numeric(), they both read: 0.3958333
When I try and compare them: (as.numeric(startTime) ==
as.numeric(expectedStartTime)) it returns FALSE.
I'm mystified. I would expect them to be true.
Perhaps a key to the riddle is how the two objects were created.
"startTime" was created by reading a text field from a socket,
converting
it
into a chron object using chron(x, "%m/$d/%Y %H:%M:%S"), then
finally I
created a time out of the chron by doing a quick butchering of the
"integer"
portion of the numeric: (times(as.numeric(x) - as.integer(x))
"expectedStartTime" was created by the command times('09:30:00')
Any suggestions? Tips? Alternative approaches? I've pulled too
many
hairs
triaging this.
All hands welcomed on this little challenge.
Big picture goal of what I'm doing: I have a list of chron objects
with
both
dates and times portion filled out and I'm trying to determine if
the
time
is a specific time (specific to the minute).
Thanks!
-Michael
--
Sarah Goslee
http://www.functionaldiversity.org
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______________________________________________
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David Winsemius, MD
West Hartford, CT
______________________________________________
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