Lubdridate: subset based on hour and minute

The trick is to realize times are stored internally in a special format,
though they can be displayed in several ways based on the internal
representation.  The trick in doing comparison with times is to make
certain what you are comparing with has also been put into the same
internal time format.  This should make clear the basis for the logical
tests:

as.numeric(test)

[1] 34200 36000 37800 39600

as.numeric(hm("10:00"))

[1] 36000

-Roy

On Jan 2, 2017, at 12:39 PM, Joe Ceradini <joeceradini at gmail.com> wrote:

Bingo! Thanks! I somehow couldn't find an example like that via google.

Joe

On Mon, Jan 2, 2017 at 1:35 PM, Roy Mendelssohn - NOAA Federal
<roy.mendelssohn at noaa.gov> wrote:

test > hm("10:00")

[1] FALSE FALSE  TRUE  TRUE

test[test > hm("10:00")]

[1] "10H 30M 0S" "11H 0M 0S"

-Roy

On Jan 2, 2017, at 12:27 PM, Joe Ceradini <joeceradini at gmail.com>

wrote:

Thanks for the reply Roy!

Perhaps you're showing me the way and I'm missing it - how would I
subset to only 1030 and 1100, excluding 1000? It seems I would need to
say, give me all time greater than 10:00, but the hours and minutes
are in separate slots, which is throwing me off.

Thanks again.

On Mon, Jan 2, 2017 at 1:13 PM, Roy Mendelssohn - NOAA Federal
<roy.mendelssohn at noaa.gov> wrote:

Hi Joe:

See below.

On Jan 2, 2017, at 12:01 PM, Joe Ceradini <joeceradini at gmail.com>

wrote:

Hi folks,

I must be missing something obvious/painfully simple here....

How do I subset a time vector based on hours AND minutes? So, in this
example, I want all time greater than 10:00, i.e., 10:30 and 11:00.
I'm working with lubridate which separates the hours and minutes into
separate slots.

require(lubridate)

test <- hm(c("9:30", "10:00", "10:30", "11:00"))
test
[1] "9H 30M 0S"  "10H 0M 0S"  "10H 30M 0S" "11H 0M 0S"

This gets 11 but not 1030
test[test at hour > 10]
[1] "11H 0M 0S"

This gets 1030 but not 11
test[test at hour > 9 & test at minute > 0]
[1] "10H 30M 0S"

test[test at hour > 9]
[1] "10H 0M 0S"  "10H 30M 0S" "11H 0M 0S"


You are using a logical "and" in your test - so the condition

"test at minute > 0" isn't met for 11:00 and therefore it doesn't show up.
as both conditions must be met  You could also do:

test[test at hour >= 10]

[1] "10H 0M 0S"  "10H 30M 0S" "11H 0M 0S"

-HTH,

Roy

Thanks and happy new year!
Joe

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Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
***Note new street address***
110 McAllister Way
Santa Cruz, CA 95060
Phone: (831)-420-3666
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e-mail: Roy.Mendelssohn at noaa.gov www: http://www.pfeg.noaa.gov/

"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"
"the arc of the moral universe is long, but it bends toward justice"

-MLK Jr.

--
Cooperative Fish and Wildlife Research Unit
Zoology and Physiology Dept.
University of Wyoming
JoeCeradini at gmail.com / 914.707.8506
wyocoopunit.org

**********************
"The contents of this message do not reflect any position of the U.S.

Government or NOAA."

**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
***Note new street address***
110 McAllister Way
Santa Cruz, CA 95060
Phone: (831)-420-3666
Fax: (831) 420-3980
e-mail: Roy.Mendelssohn at noaa.gov www: http://www.pfeg.noaa.gov/

"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"
"the arc of the moral universe is long, but it bends toward justice"

-MLK Jr.

--
Cooperative Fish and Wildlife Research Unit
Zoology and Physiology Dept.
University of Wyoming
JoeCeradini at gmail.com / 914.707.8506
wyocoopunit.org

**********************
"The contents of this message do not reflect any position of the U.S.
Government or NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
***Note new street address***
110 McAllister Way
Santa Cruz, CA 95060
Phone: (831)-420-3666
Fax: (831) 420-3980
e-mail: Roy.Mendelssohn at noaa.gov www: http://www.pfeg.noaa.gov/

"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"
"the arc of the moral universe is long, but it bends toward justice" -MLK
Jr.