Question on creating Date variable

On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

On 01 January 2013 01:29:53, David Winsemius wrote:
On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:

On 01 January 2013 00:17:50, David Winsemius wrote:
On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:

Hello all,

Let say I have following (numeric) vector:

x
[1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14
14.50
14.75 14.85 15.51 14.64

Now, I want to create a 'Date' variable (i.e. I should be able
to do
all calculations pertaining to date/time and also time-series
plotting etc.) like

2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31 11:35:00
AM, 2012-12-31 12:01:00 PM, . . . .

Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format,
given the number of items to the right of the decimal point that are
greater than 60. So will proceed on the arguably more likely
assumption that they are in fractional minutes. To recover from that
problem, one might consider:

as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
format="%M %S")
[1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
[3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
[5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
[7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
[9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
[11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
[13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
[15] "2012-12-31 00:14:38 PST"

I understand that some of those elements are not "dates". However
what I want is the ***"PM/AM" suffix*** on those elements which are
considered as Dates.

***Getting those suffix*** and doing calculations on those changed
variables is my primary concern.
That's the first time that AM/PM has bee mentioned and I suppose if
those were fractional hours rather than my guess of fractional minutes
that there might be representatives of both in the numeric data you
offered. Why don't you clarify what these number do in fact represent?
And what problem you are trying to solve?

Basically those are artificial data! Actually I do not have the
right to give out the original data in any public forum. So I
created those artificial data so that I can get the fundamental idea
...........

Each element (assuming they are legitimate time) represents the time
for a particular day when some event is pop-up. like, 11AM, 11.30AM,
12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,
15.00 etc. however I believe adding AM/PM suffice will make my
report more eye-catching.

Please let me know if you need more clarification.
So what's with the values above 59 in the minutes?
Failing an answer to that question, this code shows how to input
date-time vectors from character vectors and then output it from
date-time class to character class:

 x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01
13.14 14.50 14.75 14.85 15.51 14.64")  # This will come in as a
numeric vector

?strptime     # for the available format specifications
format( as.POSIXct(as.character(x), format="%H.%M"),  # That is the
input format
             format="%I.%M %p")     # the output format
 [1] NA         "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
 [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
[13] NA         "03.51 PM" NA

I suspect that the NA when minutes are ".00" comes from the implicit
loss of the trailing digits:

as.character(0.00)
[1] "0"

The claim that this data is proprietary and cannot presented in its
original form sound somewhat ridiculous.  Simmply post:

 dput(head(dfrm$time_data_column_name, 20))

How could that represent any disclosure of proprietary information if
presented with no context?

'How could that represent any disclosure of proprietary information if 
presented with no context? ' I must agree with you. But I just dont 
want to take any risk! (job scenario in my country is not very 
optimistic and I want to give my boss minimal chance/reason to fire!)

And secondly with your approach, I cant do any calculation. Let take 
following example:

y <- format( as.POSIXct(as.character(x), format="%H.%M"),  # That is 
the input format
             format="%I.%M %p")

y[3] - y[2]

This gives me following error:

Error in y[3] - y[2] : non-numeric argument to binary operator

I am having same error with Devid's approach as well:
y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M")
z <- format(y, format="%Y-%m-%d %I:%M %p")
z[2] - z[1]
Error in z[2] - z[1] : non-numeric argument to binary operator.

Thanks and regards,
Hello,

The format AM/PM should be for display purposes only, when you use 
format() you get a variable of class "character", not of classes 
"POSIXct" "POSIXt" . Produce a variable y with as.POSIXct (without 
AM/PM) for arithmetics and another formated for display.

Hope this helps,

Rui Barradas
Em 01-01-2013 05:40, Christofer Bogaso escreveu:
On 01 January 2013 03:00:18, David Winsemius wrote:
On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

On 01 January 2013 01:29:53, David Winsemius wrote:
On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:

On 01 January 2013 00:17:50, David Winsemius wrote:
On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:

Hello all,

Let say I have following (numeric) vector:

x
[1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14
14.50
14.75 14.85 15.51 14.64

Now, I want to create a 'Date' variable (i.e. I should be able
to do
all calculations pertaining to date/time and also time-series
plotting etc.) like

2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31 
11:35:00
AM, 2012-12-31 12:01:00 PM, . . . .

Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format,
given the number of items to the right of the decimal point that 
are
greater than 60. So will proceed on the arguably more likely
assumption that they are in fractional minutes. To recover from 
that
problem, one might consider:

as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
format="%M %S")
[1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
[3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
[5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
[7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
[9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
[11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
[13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
[15] "2012-12-31 00:14:38 PST"

I understand that some of those elements are not "dates". However
what I want is the ***"PM/AM" suffix*** on those elements which are
considered as Dates.

***Getting those suffix*** and doing calculations on those changed
variables is my primary concern.
That's the first time that AM/PM has bee mentioned and I suppose if
those were fractional hours rather than my guess of fractional 
minutes
that there might be representatives of both in the numeric data you
offered. Why don't you clarify what these number do in fact 
represent?
And what problem you are trying to solve?

Basically those are artificial data! Actually I do not have the
right to give out the original data in any public forum. So I
created those artificial data so that I can get the fundamental idea
...........

Each element (assuming they are legitimate time) represents the time
for a particular day when some event is pop-up. like, 11AM, 11.30AM,
12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,
15.00 etc. however I believe adding AM/PM suffice will make my
report more eye-catching.

Please let me know if you need more clarification.
So what's with the values above 59 in the minutes?
Failing an answer to that question, this code shows how to input
date-time vectors from character vectors and then output it from
date-time class to character class:

 x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01
13.14 14.50 14.75 14.85 15.51 14.64")  # This will come in as a
numeric vector

?strptime     # for the available format specifications
format( as.POSIXct(as.character(x), format="%H.%M"),  # That is the
input format
             format="%I.%M %p")     # the output format
 [1] NA         "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
 [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
[13] NA         "03.51 PM" NA

I suspect that the NA when minutes are ".00" comes from the implicit
loss of the trailing digits:

as.character(0.00)
[1] "0"

The claim that this data is proprietary and cannot presented in its
original form sound somewhat ridiculous.  Simmply post:

 dput(head(dfrm$time_data_column_name, 20))

How could that represent any disclosure of proprietary information if
presented with no context?

'How could that represent any disclosure of proprietary information if 
presented with no context? ' I must agree with you. But I just dont 
want to take any risk! (job scenario in my country is not very 
optimistic and I want to give my boss minimal chance/reason to fire!)

And secondly with your approach, I cant do any calculation. Let take 
following example:

y <- format( as.POSIXct(as.character(x), format="%H.%M"),  # That is 
the input format
            format="%I.%M %p")

y[3] - y[2]

This gives me following error:

Error in y[3] - y[2] : non-numeric argument to binary operator

I am having same error with Devid's approach as well:

y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H 
%M")
z <- format(y, format="%Y-%m-%d %I:%M %p")
z[2] - z[1]
Error in z[2] - z[1] : non-numeric argument to binary operator.

Thanks and regards,

______________________________________________
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.
HI,

Just by taking David's solution:
?y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M")
?y1<-data.frame(y,AM_PM=format(y,format="%p"))
?y1[3,1]-y1[4,1]
#Time difference of -40 mins
?y1[5,1]-y1[3,1]
#Time difference of -13 mins
?head(y1,2)
#??????????????????? y AM_PM
#1 2013-01-01 11:00:00??? AM
#2 2013-01-01 11:15:00??? AM
A.K.

----- Original Message -----
From: Christofer Bogaso <bogaso.christofer at gmail.com>
To: David Winsemius <dwinsemius at comcast.net>; David L Carlson <dcarlson at tamu.edu>
Cc: r-help at r-project.org
Sent: Tuesday, January 1, 2013 12:40 AM
Subject: Re: [R] Question on creating Date variable
On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

On 01 January 2013 01:29:53, David Winsemius wrote:
On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:

On 01 January 2013 00:17:50, David Winsemius wrote:
On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:

Hello all,

Let say I have following (numeric) vector:

x
[1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14
14.50
14.75 14.85 15.51 14.64

Now, I want to create a 'Date' variable (i.e. I should be able
to do
all calculations pertaining to date/time and also time-series
plotting etc.) like

2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31 11:35:00
AM, 2012-12-31 12:01:00 PM, . . . .

Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format,
given the number of items to the right of the decimal point that are
greater than 60. So will proceed on the arguably more likely
assumption that they are in fractional minutes. To recover from that
problem, one might consider:

as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
format="%M %S")
[1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
[3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
[5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
[7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
[9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
[11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
[13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
[15] "2012-12-31 00:14:38 PST"

I understand that some of those elements are not "dates". However
what I want is the ***"PM/AM" suffix*** on those elements which are
considered as Dates.

***Getting those suffix*** and doing calculations on those changed
variables is my primary concern.
That's the first time that AM/PM has bee mentioned and I suppose if
those were fractional hours rather than my guess of fractional minutes
that there might be representatives of both in the numeric data you
offered. Why don't you clarify what these number do in fact represent?
And what problem you are trying to solve?

Basically those are artificial data! Actually I do not have the
right to give out the original data in any public forum. So I
created those artificial data so that I can get the fundamental idea
...........

Each element (assuming they are legitimate time) represents the time
for a particular day when some event is pop-up. like, 11AM, 11.30AM,
12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,
15.00 etc. however I believe adding AM/PM suffice will make my
report more eye-catching.

Please let me know if you need more clarification.
So what's with the values above 59 in the minutes?
Failing an answer to that question, this code shows how to input
date-time vectors from character vectors and then output it from
date-time class to character class:

? x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01
13.14 14.50 14.75 14.85 15.51 14.64")? # This will come in as a
numeric vector

?strptime? ?  # for the available format specifications
format( as.POSIXct(as.character(x), format="%H.%M"),? # That is the
input format
? ? ? ? ? ? ? format="%I.%M %p")? ?  # the output format
? [1] NA? ? ? ?  "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
? [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
[13] NA? ? ? ?  "03.51 PM" NA

I suspect that the NA when minutes are ".00" comes from the implicit
loss of the trailing digits:

as.character(0.00)
[1] "0"

The claim that this data is proprietary and cannot presented in its
original form sound somewhat ridiculous.? Simmply post:

? dput(head(dfrm$time_data_column_name, 20))

How could that represent any disclosure of proprietary information if
presented with no context?

'How could that represent any disclosure of proprietary information if 
presented with no context? ' I must agree with you. But I just dont 
want to take any risk! (job scenario in my country is not very 
optimistic and I want to give my boss minimal chance/reason to fire!)

And secondly with your approach, I cant do any calculation. Let take 
following example:

y <- format( as.POSIXct(as.character(x), format="%H.%M"),? # That is 
the input format
? ? ? ? ? ?  format="%I.%M %p")

y[3] - y[2]

This gives me following error:

Error in y[3] - y[2] : non-numeric argument to binary operator

I am having same error with Devid's approach as well:
y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M")
z <- format(y, format="%Y-%m-%d %I:%M %p")
z[2] - z[1]
Error in z[2] - z[1] : non-numeric argument to binary operator.

Thanks and regards,

______________________________________________
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.

On 01 January 2013 03:00:18, David Winsemius wrote:
On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

On 01 January 2013 01:29:53, David Winsemius wrote:
On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:

On 01 January 2013 00:17:50, David Winsemius wrote:
On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:

Hello all,

Let say I have following (numeric) vector:

x
[1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14
14.50
14.75 14.85 15.51 14.64

Now, I want to create a 'Date' variable (i.e. I should be able
to do
all calculations pertaining to date/time and also time-series
plotting etc.) like

2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31  
11:35:00
AM, 2012-12-31 12:01:00 PM, . . . .

Those _times_ ( _not_ Dates) cannot possibly be in %M.%S"  
format,
given the number of items to the right of the decimal point  
that are
greater than 60. So will proceed on the arguably more likely
assumption that they are in fractional minutes. To recover  
from that
problem, one might consider:

as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
format="%M %S")
[1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
[3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
[5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
[7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
[9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
[11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
[13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
[15] "2012-12-31 00:14:38 PST"

I understand that some of those elements are not "dates". However
what I want is the ***"PM/AM" suffix*** on those elements which  
are
considered as Dates.

***Getting those suffix*** and doing calculations on those  
changed
variables is my primary concern.
That's the first time that AM/PM has bee mentioned and I suppose  
if
those were fractional hours rather than my guess of fractional  
minutes
that there might be representatives of both in the numeric data  
you
offered. Why don't you clarify what these number do in fact  
represent?
And what problem you are trying to solve?

Basically those are artificial data! Actually I do not have the
right to give out the original data in any public forum. So I
created those artificial data so that I can get the fundamental  
idea
...........

Each element (assuming they are legitimate time) represents the  
time
for a particular day when some event is pop-up. like, 11AM,  
11.30AM,
12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,
15.00 etc. however I believe adding AM/PM suffice will make my
report more eye-catching.

Please let me know if you need more clarification.
So what's with the values above 59 in the minutes?
Failing an answer to that question, this code shows how to input
date-time vectors from character vectors and then output it from
date-time class to character class:

x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01
13.14 14.50 14.75 14.85 15.51 14.64")  # This will come in as a
numeric vector

?strptime     # for the available format specifications
format( as.POSIXct(as.character(x), format="%H.%M"),  # That is the
input format
            format="%I.%M %p")     # the output format
[1] NA         "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
[7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
[13] NA         "03.51 PM" NA

I suspect that the NA when minutes are ".00" comes from the implicit
loss of the trailing digits:

as.character(0.00)
[1] "0"

The claim that this data is proprietary and cannot presented in its
original form sound somewhat ridiculous.  Simmply post:

dput(head(dfrm$time_data_column_name, 20))

How could that represent any disclosure of proprietary information if
presented with no context?

'How could that represent any disclosure of proprietary information  
if presented with no context? ' I must agree with you. But I just  
dont want to take any risk! (job scenario in my country is not very  
optimistic and I want to give my boss minimal chance/reason to fire!)

And secondly with your approach, I cant do any calculation. Let take  
following example:

y <- format( as.POSIXct(as.character(x), format="%H.%M"),  # That is  
the input format
           format="%I.%M %p")
That was my code. If you will need to apply numeric operators then you  
should be storing the POSIXct value as an intermediate:

dt_time <- as.POSIXct(as.character(x), format="%H.%M")

out_time <- format( dt_time,
            format="%I.%M %p")
dt_time[3] - dt_time[2]
David.

>
> y[3] - y[2]
>
> This gives me following error:
>
> Error in y[3] - y[2] : non-numeric argument to binary operator
>
> I am having same error with Devid's approach as well:
>
>> y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),  
>> format="%H %M")
>> z <- format(y, format="%Y-%m-%d %I:%M %p")
>> z[2] - z[1]
> Error in z[2] - z[1] : non-numeric argument to binary operator.
>
> Thanks and regards,
>
>
>

David Winsemius, MD
Alameda, CA, USA
# can use sprintf to convert to a number with 2 digit fractions
x <- c(10.30, 11, 11.01, 11.09, 11.15, 11.59, 12, 13)
as.POSIXct(sprintf("%.2f", x), format = "%H.%M")
[1] "2013-01-01 10:30:00 EST" "2013-01-01 11:00:00 EST" "2013-01-01
11:01:00 EST"
[4] "2013-01-01 11:09:00 EST" "2013-01-01 11:15:00 EST" "2013-01-01
11:59:00 EST"
[7] "2013-01-01 12:00:00 EST" "2013-01-01 13:00:00 EST"

HI,

Just by taking David's solution:
 y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M")
 y1<-data.frame(y,AM_PM=format(y,format="%p"))
 y1[3,1]-y1[4,1]
#Time difference of -40 mins
 y1[5,1]-y1[3,1]
#Time difference of -13 mins
 head(y1,2)
#                    y AM_PM
#1 2013-01-01 11:00:00    AM
#2 2013-01-01 11:15:00    AM
A.K.

----- Original Message -----
From: Christofer Bogaso <bogaso.christofer at gmail.com>
To: David Winsemius <dwinsemius at comcast.net>; David L Carlson <dcarlson at tamu.edu>
Cc: r-help at r-project.org
Sent: Tuesday, January 1, 2013 12:40 AM
Subject: Re: [R] Question on creating Date variable

On 01 January 2013 03:00:18, David Winsemius wrote:
On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

On 01 January 2013 01:29:53, David Winsemius wrote:
On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:

On 01 January 2013 00:17:50, David Winsemius wrote:
On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:

Hello all,

Let say I have following (numeric) vector:

x
[1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14
14.50
14.75 14.85 15.51 14.64

Now, I want to create a 'Date' variable (i.e. I should be able
to do
all calculations pertaining to date/time and also time-series
plotting etc.) like

2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31 11:35:00
AM, 2012-12-31 12:01:00 PM, . . . .

Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format,
given the number of items to the right of the decimal point that are
greater than 60. So will proceed on the arguably more likely
assumption that they are in fractional minutes. To recover from that
problem, one might consider:

as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
format="%M %S")
[1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
[3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
[5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
[7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
[9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
[11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
[13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
[15] "2012-12-31 00:14:38 PST"

I understand that some of those elements are not "dates". However
what I want is the ***"PM/AM" suffix*** on those elements which are
considered as Dates.

***Getting those suffix*** and doing calculations on those changed
variables is my primary concern.
That's the first time that AM/PM has bee mentioned and I suppose if
those were fractional hours rather than my guess of fractional minutes
that there might be representatives of both in the numeric data you
offered. Why don't you clarify what these number do in fact represent?
And what problem you are trying to solve?

Basically those are artificial data! Actually I do not have the
right to give out the original data in any public forum. So I
created those artificial data so that I can get the fundamental idea
...........

Each element (assuming they are legitimate time) represents the time
for a particular day when some event is pop-up. like, 11AM, 11.30AM,
12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,
15.00 etc. however I believe adding AM/PM suffice will make my
report more eye-catching.

Please let me know if you need more clarification.
So what's with the values above 59 in the minutes?
Failing an answer to that question, this code shows how to input
date-time vectors from character vectors and then output it from
date-time class to character class:

 x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01
13.14 14.50 14.75 14.85 15.51 14.64")  # This will come in as a
numeric vector

?strptime     # for the available format specifications
format( as.POSIXct(as.character(x), format="%H.%M"),  # That is the
input format
             format="%I.%M %p")     # the output format
 [1] NA         "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
 [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
[13] NA         "03.51 PM" NA

I suspect that the NA when minutes are ".00" comes from the implicit
loss of the trailing digits:

as.character(0.00)
[1] "0"

The claim that this data is proprietary and cannot presented in its
original form sound somewhat ridiculous.  Simmply post:

 dput(head(dfrm$time_data_column_name, 20))

How could that represent any disclosure of proprietary information if
presented with no context?

'How could that represent any disclosure of proprietary information if
presented with no context? ' I must agree with you. But I just dont
want to take any risk! (job scenario in my country is not very
optimistic and I want to give my boss minimal chance/reason to fire!)

And secondly with your approach, I cant do any calculation. Let take
following example:

y <- format( as.POSIXct(as.character(x), format="%H.%M"),  # That is
the input format
             format="%I.%M %p")

y[3] - y[2]

This gives me following error:

Error in y[3] - y[2] : non-numeric argument to binary operator

I am having same error with Devid's approach as well:

y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M")
z <- format(y, format="%Y-%m-%d %I:%M %p")
z[2] - z[1]
Error in z[2] - z[1] : non-numeric argument to binary operator.

Thanks and regards,

______________________________________________
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.

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

# can use sprintf to convert to a number with 2 digit fractions
Useful procedure to prevent loss of trailing ".00"'s, ... but just to  
clarify, sprintf never returns a numeric class object, but rather  
returns a character representation of one. (Which is an appropriate  
class for `as.POSIXct`.)
x <- c(10.30, 11, 11.01, 11.09, 11.15, 11.59, 12, 13)
as.POSIXct(sprintf("%.2f", x), format = "%H.%M")
[1] "2013-01-01 10:30:00 EST" "2013-01-01 11:00:00 EST" "2013-01-01
11:01:00 EST"
[4] "2013-01-01 11:09:00 EST" "2013-01-01 11:15:00 EST" "2013-01-01
11:59:00 EST"
[7] "2013-01-01 12:00:00 EST" "2013-01-01 13:00:00 EST"
Just as those values are printed character representations of what is  
internally a numeric vector even though it will not admit to being  
such until coerced:

 > Sys.Date()
[1] "2013-01-01"
 > is.numeric(Sys.Date())
[1] FALSE
 > as.numeric(Sys.Date())
[1] 15706
 > as.numeric(as.POSIXct(Sys.Date()))
[1] 1356998400
 >
David.
>>
>
>
> On Tue, Jan 1, 2013 at 11:09 AM, arun <smartpink111 at yahoo.com> wrote:
>> HI,
>>
>> Just by taking David's solution:
>> y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),  
>> format="%H %M")
>> y1<-data.frame(y,AM_PM=format(y,format="%p"))
>> y1[3,1]-y1[4,1]
>> #Time difference of -40 mins
>> y1[5,1]-y1[3,1]
>> #Time difference of -13 mins
>> head(y1,2)
>> #                    y AM_PM
>> #1 2013-01-01 11:00:00    AM
>> #2 2013-01-01 11:15:00    AM
>> A.K.
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: Christofer Bogaso <bogaso.christofer at gmail.com>
>> To: David Winsemius <dwinsemius at comcast.net>; David L Carlson <dcarlson at tamu.edu 
>> >
>> Cc: r-help at r-project.org
>> Sent: Tuesday, January 1, 2013 12:40 AM
>> Subject: Re: [R] Question on creating Date variable
>>
>> On 01 January 2013 03:00:18, David Winsemius wrote:
>>>
>>> On Dec 31, 2012, at 11:57 AM, David Winsemius wrote:
>>>
>>>>
>>>> On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:
>>>>
>>>>> On 01 January 2013 01:29:53, David Winsemius wrote:
>>>>>>
>>>>>> On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:
>>>>>>
>>>>>>> On 01 January 2013 00:17:50, David Winsemius wrote:
>>>>>>>>
>>>>>>>> On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:
>>>>>>>>
>>>>>>>>> Hello all,
>>>>>>>>>
>>>>>>>>> Let say I have following (numeric) vector:
>>>>>>>>>
>>>>>>>>>> x
>>>>>>>>> [1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01  
>>>>>>>>> 13.14
>>>>>>>>> 14.50
>>>>>>>>> 14.75 14.85 15.51 14.64
>>>>>>>>>
>>>>>>>>> Now, I want to create a 'Date' variable (i.e. I should be able
>>>>>>>>> to do
>>>>>>>>> all calculations pertaining to date/time and also time-series
>>>>>>>>> plotting etc.) like
>>>>>>>>>
>>>>>>>>> 2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31  
>>>>>>>>> 11:35:00
>>>>>>>>> AM, 2012-12-31 12:01:00 PM, . . . .
>>>>>>>>>
>>>>>>>>
>>>>>>>> Those _times_ ( _not_ Dates) cannot possibly be in %M.%S"  
>>>>>>>> format,
>>>>>>>> given the number of items to the right of the decimal point  
>>>>>>>> that are
>>>>>>>> greater than 60. So will proceed on the arguably more likely
>>>>>>>> assumption that they are in fractional minutes. To recover  
>>>>>>>> from that
>>>>>>>> problem, one might consider:
>>>>>>>>
>>>>>>>>> as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),
>>>>>>>> format="%M %S")
>>>>>>>> [1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
>>>>>>>> [3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
>>>>>>>> [5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
>>>>>>>> [7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
>>>>>>>> [9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
>>>>>>>> [11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
>>>>>>>> [13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
>>>>>>>> [15] "2012-12-31 00:14:38 PST"
>>>>>>>>
>>>>>>>
>>>>>>> I understand that some of those elements are not "dates".  
>>>>>>> However
>>>>>>> what I want is the ***"PM/AM" suffix*** on those elements  
>>>>>>> which are
>>>>>>> considered as Dates.
>>>>>>>
>>>>>>> ***Getting those suffix*** and doing calculations on those  
>>>>>>> changed
>>>>>>> variables is my primary concern.
>>>>>>
>>>>>> That's the first time that AM/PM has bee mentioned and I  
>>>>>> suppose if
>>>>>> those were fractional hours rather than my guess of fractional  
>>>>>> minutes
>>>>>> that there might be representatives of both in the numeric data  
>>>>>> you
>>>>>> offered. Why don't you clarify what these number do in fact  
>>>>>> represent?
>>>>>> And what problem you are trying to solve?
>>>>>>
>>>>>
>>>>> Basically those are artificial data! Actually I do not have the
>>>>> right to give out the original data in any public forum. So I
>>>>> created those artificial data so that I can get the fundamental  
>>>>> idea
>>>>> ...........
>>>>>
>>>>> Each element (assuming they are legitimate time) represents the  
>>>>> time
>>>>> for a particular day when some event is pop-up. like, 11AM,  
>>>>> 11.30AM,
>>>>> 12.05PM etc.. I could work with something like 11.00, 11.30,  
>>>>> 12.05,
>>>>> 15.00 etc. however I believe adding AM/PM suffice will make my
>>>>> report more eye-catching.
>>>>>
>>>>> Please let me know if you need more clarification.
>>>>
>>>> So what's with the values above 59 in the minutes?
>>>
>>> Failing an answer to that question, this code shows how to input
>>> date-time vectors from character vectors and then output it from
>>> date-time class to character class:
>>>
>>> x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35  
>>> 14.01
>>> 13.14 14.50 14.75 14.85 15.51 14.64")  # This will come in as a
>>> numeric vector
>>>
>>> ?strptime     # for the available format specifications
>>> format( as.POSIXct(as.character(x), format="%H.%M"),  # That is the
>>> input format
>>>             format="%I.%M %p")     # the output format
>>> [1] NA         "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA
>>> [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA
>>> [13] NA         "03.51 PM" NA
>>>
>>> I suspect that the NA when minutes are ".00" comes from the implicit
>>> loss of the trailing digits:
>>>
>>>> as.character(0.00)
>>> [1] "0"
>>>
>>> The claim that this data is proprietary and cannot presented in its
>>> original form sound somewhat ridiculous.  Simmply post:
>>>
>>> dput(head(dfrm$time_data_column_name, 20))
>>>
>>> How could that represent any disclosure of proprietary information  
>>> if
>>> presented with no context?
>>>
>>
>> 'How could that represent any disclosure of proprietary information  
>> if
>> presented with no context? ' I must agree with you. But I just dont
>> want to take any risk! (job scenario in my country is not very
>> optimistic and I want to give my boss minimal chance/reason to fire!)
>>
>> And secondly with your approach, I cant do any calculation. Let take
>> following example:
>>
>> y <- format( as.POSIXct(as.character(x), format="%H.%M"),  # That is
>> the input format
>>             format="%I.%M %p")
>>
>> y[3] - y[2]
>>
>> This gives me following error:
>>
>> Error in y[3] - y[2] : non-numeric argument to binary operator
>>
>> I am having same error with Devid's approach as well:
>>
>>> y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),  
>>> format="%H %M")
>>> z <- format(y, format="%Y-%m-%d %I:%M %p")
>>> z[2] - z[1]
>> Error in z[2] - z[1] : non-numeric argument to binary operator.
>>
>> Thanks and regards,
>>
>> ______________________________________________
>> 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.
>>
>>
>> ______________________________________________
>> 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.
>
>
>
> -- 
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
>
> ______________________________________________
> 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.

David Winsemius, MD
Alameda, CA, USA