Re: [R] Converting time format

[Parkhurst, David]

Thank you.

From: Rui Barradas 
Date: Monday, September 19, 2022 at 1:28 PM
To: Parkhurst, David , R-help@r-project.org 

Subject: Re: [R] Converting time format
Hello,

I will run the examples below with the following data:


x <- c("12:00", "12:15", "12:30", "12:45", "13:00", "13:15", "13:30",
"13:45", "14:00", "14:15", "14:30", "14:45", "15:00", "15:15",
"15:30", "15:45", "16:00", "16:15", "16:30", "16:45", "17:00",
"17:15", "17:30", "17:45", "18:00")
b <- data.frame(time = x, myvar = sin(2*pi*seq_along(x)/length(x)))


Are they are saying is true, the vector b$myvar is a character vector
and that's what is being displayed.

In what follows I will first give examples of base graphics. The times
are first coerced to a proper time class with package chron.



library(chron)

b$time <- as.times(b$time)

# see ?plot.default for the meaning of
# argument 'type'
plot(myvar ~ time, b)
plot(myvar ~ time, b, type = "l")
plot(myvar ~ time, b, type = "b")



With ggplot2, there is no need to load a date/time class package, R can
do it with ?as.POSXct but the labels are datetime_breaks and
datetime_labels.



library(ggplot2)

b |>
   dplyr::mutate(time = paste(Sys.Date(), time),
 time = as.POSIXct(time)) |>
   ggplot(aes(time, myvar)) +
   geom_line() +
   geom_point() +
   scale_x_datetime(date_breaks = "1 hour", date_labels = "%H:%M") +
   theme_bw()



Hope this helps,

Rui Barradas


�s 01:56 de 19/09/2022, Parkhurst, David escreveu:
> I have a dataframe obtained using read.csv from an excel file.  Its first 
> column is times, running from 18:00 to 19:30.  If I want to plot other 
> columns against time, do I need to convert those somehow, and how would I do 
> that?
>
> If I run plot(b$time,b$myvar) I get a decent plot, but a friend suggests that 
> R is just treating those numbers as text, and putting them in alphabetical 
> order.  True?
>
>[[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.

Re: [R] Converting time format

[Parkhurst, David]

Thank you.  I�ll see what I can do with that.

From: Rui Barradas 
Date: Monday, September 19, 2022 at 1:28 PM
To: Parkhurst, David , r-help@r-project.org 

Subject: Re: [R] Converting time format
Hello,

I will run the examples below with the following data:


x <- c("12:00", "12:15", "12:30", "12:45", "13:00", "13:15", "13:30",
"13:45", "14:00", "14:15", "14:30", "14:45", "15:00", "15:15",
"15:30", "15:45", "16:00", "16:15", "16:30", "16:45", "17:00",
"17:15", "17:30", "17:45", "18:00")
b <- data.frame(time = x, myvar = sin(2*pi*seq_along(x)/length(x)))


Are they are saying is true, the vector b$myvar is a character vector
and that's what is being displayed.

In what follows I will first give examples of base graphics. The times
are first coerced to a proper time class with package chron.



library(chron)

b$time <- as.times(b$time)

# see ?plot.default for the meaning of
# argument 'type'
plot(myvar ~ time, b)
plot(myvar ~ time, b, type = "l")
plot(myvar ~ time, b, type = "b")



With ggplot2, there is no need to load a date/time class package, R can
do it with ?as.POSXct but the labels are datetime_breaks and
datetime_labels.



library(ggplot2)

b |>
   dplyr::mutate(time = paste(Sys.Date(), time),
 time = as.POSIXct(time)) |>
   ggplot(aes(time, myvar)) +
   geom_line() +
   geom_point() +
   scale_x_datetime(date_breaks = "1 hour", date_labels = "%H:%M") +
   theme_bw()



Hope this helps,

Rui Barradas


�s 01:56 de 19/09/2022, Parkhurst, David escreveu:
> I have a dataframe obtained using read.csv from an excel file.  Its first 
> column is times, running from 18:00 to 19:30.  If I want to plot other 
> columns against time, do I need to convert those somehow, and how would I do 
> that?
>
> If I run plot(b$time,b$myvar) I get a decent plot, but a friend suggests that 
> R is just treating those numbers as text, and putting them in alphabetical 
> order.  True?
>
>[[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.

Re: [R] Converting time format

[Rui Barradas]

Hello,

I will run the examples below with the following data:


x <- c("12:00", "12:15", "12:30", "12:45", "13:00", "13:15", "13:30",
   "13:45", "14:00", "14:15", "14:30", "14:45", "15:00", "15:15",
   "15:30", "15:45", "16:00", "16:15", "16:30", "16:45", "17:00",
   "17:15", "17:30", "17:45", "18:00")
b <- data.frame(time = x, myvar = sin(2*pi*seq_along(x)/length(x)))


Are they are saying is true, the vector b$myvar is a character vector 
and that's what is being displayed.


In what follows I will first give examples of base graphics. The times 
are first coerced to a proper time class with package chron.




library(chron)

b$time <- as.times(b$time)

# see ?plot.default for the meaning of
# argument 'type'
plot(myvar ~ time, b)
plot(myvar ~ time, b, type = "l")
plot(myvar ~ time, b, type = "b")



With ggplot2, there is no need to load a date/time class package, R can 
do it with ?as.POSXct but the labels are datetime_breaks and 
datetime_labels.




library(ggplot2)

b |>
  dplyr::mutate(time = paste(Sys.Date(), time),
time = as.POSIXct(time)) |>
  ggplot(aes(time, myvar)) +
  geom_line() +
  geom_point() +
  scale_x_datetime(date_breaks = "1 hour", date_labels = "%H:%M") +
  theme_bw()



Hope this helps,

Rui Barradas


Às 01:56 de 19/09/2022, Parkhurst, David escreveu:

I have a dataframe obtained using read.csv from an excel file.  Its first 
column is times, running from 18:00 to 19:30.  If I want to plot other columns 
against time, do I need to convert those somehow, and how would I do that?

If I run plot(b$time,b$myvar) I get a decent plot, but a friend suggests that R 
is just treating those numbers as text, and putting them in alphabetical order. 
 True?

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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 -- To UNSUBSCRIBE and more, see
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.

Re: [R] Converting time format

[Eric Berger]

What is the output of

> class(b$time)

?

Also, start sending your emails in plaint text format, if possible.

On Mon, Sep 19, 2022 at 2:12 PM Parkhurst, David  wrote:
>
> I have a dataframe obtained using read.csv from an excel file.  Its first 
> column is times, running from 18:00 to 19:30.  If I want to plot other 
> columns against time, do I need to convert those somehow, and how would I do 
> that?
>
> If I run plot(b$time,b$myvar) I get a decent plot, but a friend suggests that 
> R is just treating those numbers as text, and putting them in alphabetical 
> order.  True?
>
> [[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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 -- To UNSUBSCRIBE and more, see
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] Converting time format

[Parkhurst, David]

I have a dataframe obtained using read.csv from an excel file.  Its first 
column is times, running from 18:00 to 19:30.  If I want to plot other columns 
against time, do I need to convert those somehow, and how would I do that?

If I run plot(b$time,b$myvar) I get a decent plot, but a friend suggests that R 
is just treating those numbers as text, and putting them in alphabetical order. 
 True?

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.

Re: [R] converting time format

[Jim Lemon]

Sure:

df.count.mon$time<-format(as.Date(paste(df.count.mon$year,  df.count.mon$mon,1),
 '%Y %m %d'),"%Y %m")
> df.count.mon
   count year montime
1 22 2014   1 2014 01
2 12 2014   2 2014 02
...

Jim

On Thu, Feb 23, 2017 at 8:18 AM, lily li  wrote:
> Yes, it is a little different. Is there a way to get '-mm' format?
> Thanks.
>
> On Wed, Feb 22, 2017 at 2:10 PM, Jim Lemon  wrote:
>>
>> Hi Lily.
>> Two problems. You have named the month field "mon" and then refer to
>> it as "month". Second, as the resolution of as.Date is days, it can't
>> produce a valid date without specifying the day. Thus:
>>
>> df.count.mon<-data.frame(count=sample(1:24,24),
>>  year=rep(2014:2015,each=2),mon=rep(1:12,2))
>> # make each day the first day of the month
>> df.count.mon$time<-
>>  as.Date(paste(df.count.mon$year, df.count.mon$mon,1),
>>  '%Y %m %d')
>> df.count.mon
>>count year mon   time
>> 1 22 2014   1 2014-01-01
>> 2 12 2014   2 2014-02-01
>> ...
>> You will get values, but I don't think they are the ones you want.
>>
>> Jim
>>
>> On Thu, Feb 23, 2017 at 6:33 AM, lily li  wrote:
>> > Hi R users,
>> >
>> > I have a dataframe, with year, month, day, and other variables. I wanted
>> > to
>> > calculated monthly values of the variables. For example, there is one
>> > variable called 'count'. I use the code below to convert daily data to
>> > monthly data.
>> >
>> > df.count.mon = aggregate(count ~ year+month, data= df, sum)
>> >
>> > The new dataframe has three columns: year, month, and count. Now I want
>> > to
>> > add one more column as 'time', which has the format '-mm'. I use the
>> > code below but the new column has all NA values. What is the problem and
>> > how to solve it?
>> >
>> > df.count.mon$time = as.Date(paste(df.count.mon$year,
>> > df.count.mon$month),
>> > '%Y %m')
>> >
>> > I had experience to add one more column with the format '-mm-dd',
>> > which
>> > works, but not with monthly format. Thanks for your help.
>> >
>> > [[alternative HTML version deleted]]
>> >
>> > __
>> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > 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 -- To UNSUBSCRIBE and more, see
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.

Re: [R] converting time format

[lily li]

Yes, it is a little different. Is there a way to get '-mm' format?
Thanks.

On Wed, Feb 22, 2017 at 2:10 PM, Jim Lemon  wrote:

> Hi Lily.
> Two problems. You have named the month field "mon" and then refer to
> it as "month". Second, as the resolution of as.Date is days, it can't
> produce a valid date without specifying the day. Thus:
>
> df.count.mon<-data.frame(count=sample(1:24,24),
>  year=rep(2014:2015,each=2),mon=rep(1:12,2))
> # make each day the first day of the month
> df.count.mon$time<-
>  as.Date(paste(df.count.mon$year, df.count.mon$mon,1),
>  '%Y %m %d')
> df.count.mon
>count year mon   time
> 1 22 2014   1 2014-01-01
> 2 12 2014   2 2014-02-01
> ...
> You will get values, but I don't think they are the ones you want.
>
> Jim
>
> On Thu, Feb 23, 2017 at 6:33 AM, lily li  wrote:
> > Hi R users,
> >
> > I have a dataframe, with year, month, day, and other variables. I wanted
> to
> > calculated monthly values of the variables. For example, there is one
> > variable called 'count'. I use the code below to convert daily data to
> > monthly data.
> >
> > df.count.mon = aggregate(count ~ year+month, data= df, sum)
> >
> > The new dataframe has three columns: year, month, and count. Now I want
> to
> > add one more column as 'time', which has the format '-mm'. I use the
> > code below but the new column has all NA values. What is the problem and
> > how to solve it?
> >
> > df.count.mon$time = as.Date(paste(df.count.mon$year,
> df.count.mon$month),
> > '%Y %m')
> >
> > I had experience to add one more column with the format '-mm-dd',
> which
> > works, but not with monthly format. Thanks for your help.
> >
> > [[alternative HTML version deleted]]
> >
> > __
> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.

Re: [R] converting time format

[Jim Lemon]

Hi Lily.
Two problems. You have named the month field "mon" and then refer to
it as "month". Second, as the resolution of as.Date is days, it can't
produce a valid date without specifying the day. Thus:

df.count.mon<-data.frame(count=sample(1:24,24),
 year=rep(2014:2015,each=2),mon=rep(1:12,2))
# make each day the first day of the month
df.count.mon$time<-
 as.Date(paste(df.count.mon$year, df.count.mon$mon,1),
 '%Y %m %d')
df.count.mon
   count year mon   time
1 22 2014   1 2014-01-01
2 12 2014   2 2014-02-01
...
You will get values, but I don't think they are the ones you want.

Jim

On Thu, Feb 23, 2017 at 6:33 AM, lily li  wrote:
> Hi R users,
>
> I have a dataframe, with year, month, day, and other variables. I wanted to
> calculated monthly values of the variables. For example, there is one
> variable called 'count'. I use the code below to convert daily data to
> monthly data.
>
> df.count.mon = aggregate(count ~ year+month, data= df, sum)
>
> The new dataframe has three columns: year, month, and count. Now I want to
> add one more column as 'time', which has the format '-mm'. I use the
> code below but the new column has all NA values. What is the problem and
> how to solve it?
>
> df.count.mon$time = as.Date(paste(df.count.mon$year, df.count.mon$month),
> '%Y %m')
>
> I had experience to add one more column with the format '-mm-dd', which
> works, but not with monthly format. Thanks for your help.
>
> [[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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 -- To UNSUBSCRIBE and more, see
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] converting time format

[lily li]

Hi R users,

I have a dataframe, with year, month, day, and other variables. I wanted to
calculated monthly values of the variables. For example, there is one
variable called 'count'. I use the code below to convert daily data to
monthly data.

df.count.mon = aggregate(count ~ year+month, data= df, sum)

The new dataframe has three columns: year, month, and count. Now I want to
add one more column as 'time', which has the format '-mm'. I use the
code below but the new column has all NA values. What is the problem and
how to solve it?

df.count.mon$time = as.Date(paste(df.count.mon$year, df.count.mon$month),
'%Y %m')

I had experience to add one more column with the format '-mm-dd', which
works, but not with monthly format. Thanks for your help.

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.