Converting string to System.Time.ClockTime

dokondr

8 Dec 2011 8 Dec '11

8:16 a.m.

Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ? Thanks!

Attachments:

attachment.html (text/html — 172 bytes)

Show replies by date

I'm not sure if you really need ClockTime (from old-time), but if you don't, the types from the 'time' package are all parseable with `parseTime` [1]. Erik [1] http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-F... On Thu, Dec 8, 2011 at 14:16, dokondr wrote:

...

Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ?

Thanks!

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

dokondr

9:30 a.m.

I need to parse time strings like "Wed, 07 Dec 2011 10:09:21 +0000" to a type that: 1) implements Eq, Ord 2) is numerical, so I could subtract one value from another to find the difference or interval length To answer 1) requirement I wrote the following snippet. Yet I could not subtract UTCTime values. How can I convert them to milliseconds? import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2 t = compare t1 t2 tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p" On Thu, Dec 8, 2011 at 6:12 PM, Erik Hesselink wrote:

...

I'm not sure if you really need ClockTime (from old-time), but if you don't, the types from the 'time' package are all parseable with `parseTime` [1].

Erik

[1]

...

http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-F...

On Thu, Dec 8, 2011 at 14:16, dokondr wrote:

...
Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ?

Thanks!

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

dokondr

10:01 a.m.

Now, when I have managed to convert UTCTime to seconds (see code below) I got stuck trying to convert from UTCTime to CalendarTime, how to do this? import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe import Data.Time.Clock.POSIX s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2 pt1 = utcTimeToPOSIXSeconds t1 -- :: UTCTime -> POSIXTime pt2 = utcTimeToPOSIXSeconds t2 pt3 = pt1 + (pt2 - pt1) / 2 t3 = posixSecondsToUTCTime pt3 t = compare t1 t2 tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p" -- timeFormat1 = "%m/%d/%Y %l:%M:%S %p" On Thu, Dec 8, 2011 at 6:30 PM, dokondr wrote:

...

I need to parse time strings like "Wed, 07 Dec 2011 10:09:21 +0000" to a type that: 1) implements Eq, Ord 2) is numerical, so I could subtract one value from another to find the difference or interval length

To answer 1) requirement I wrote the following snippet. Yet I could not subtract UTCTime values. How can I convert them to milliseconds?

import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2

t = compare t1 t2

tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time

timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p"

On Thu, Dec 8, 2011 at 6:12 PM, Erik Hesselink wrote:

...
I'm not sure if you really need ClockTime (from old-time), but if you don't, the types from the 'time' package are all parseable with `parseTime` [1].

Erik

[1]

...
http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-F...

On Thu, Dec 8, 2011 at 14:16, dokondr wrote:

...
Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ?

Thanks!

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Antoine Latter

10:13 a.m.

On Thu, Dec 8, 2011 at 9:01 AM, dokondr wrote:

...

Now, when I have managed to convert UTCTime to seconds (see code below) I got stuck trying to convert from UTCTime to CalendarTime, how to do this?

It might be easier to use 'diffUTCTime' and 'addUTCTime' instead of converting to and from POSIX seconds. What do you need the 'CalendarTime' for? I recommend not mixing the 'time' and 'old-time' packages if you can avoid it. If you really need to for inter-operating with some other library, it looks like you can use the 'datetime' package to convert from a UTCTime to a ClockTime, and then you can use the 'old-time' package to convert from a 'ClockTime' to a 'CalendarTime'. Antoine

...

import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe import Data.Time.Clock.POSIX

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2 pt1 = utcTimeToPOSIXSeconds t1 -- :: UTCTime -> POSIXTime pt2 = utcTimeToPOSIXSeconds t2 pt3 = pt1 + (pt2 - pt1) / 2 t3 = posixSecondsToUTCTime pt3

t = compare t1 t2

tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime)    where      tryFormat time         | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime         | otherwise = time

     timeFormat1 = "%a, %d %b %Y %T %z"      timeFormat2 = "%m/%e/%Y %l:%M:%S %p" -- timeFormat1 = "%m/%d/%Y %l:%M:%S %p"

On Thu, Dec 8, 2011 at 6:30 PM, dokondr wrote:

...
I need to parse time strings like "Wed, 07 Dec 2011 10:09:21 +0000" to a type that: 1) implements Eq, Ord 2) is numerical, so I could subtract one value from another to find the difference or interval length

To answer 1) requirement I wrote the following snippet. Yet I could not subtract UTCTime values. How can I convert them to milliseconds?

import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2

t = compare t1 t2

tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime)    where      tryFormat time         | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime         | otherwise = time

     timeFormat1 = "%a, %d %b %Y %T %z"      timeFormat2 = "%m/%e/%Y %l:%M:%S %p"

On Thu, Dec 8, 2011 at 6:12 PM, Erik Hesselink wrote:

...
I'm not sure if you really need ClockTime (from old-time), but if you don't, the types from the 'time' package are all parseable with `parseTime` [1].

Erik

[1] http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-F...

On Thu, Dec 8, 2011 at 14:16, dokondr wrote:

...
Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ?

Thanks!

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Antoine Latter

10:17 a.m.

On Thu, Dec 8, 2011 at 9:13 AM, Antoine Latter wrote:

...

On Thu, Dec 8, 2011 at 9:01 AM, dokondr wrote:

...
Now, when I have managed to convert UTCTime to seconds (see code below) I got stuck trying to convert from UTCTime to CalendarTime, how to do this?

It might be easier to use 'diffUTCTime' and 'addUTCTime' instead of converting to and from POSIX seconds.

For those reading along at home, 'addUTCTime' and 'diffUTCTime' are implemented in terms of 'posixSecondsToUTCTime' and 'utcTimeToPOSIXSeconds'. So it's pretty similar in the end. Antoine

dokondr

10:30 a.m.

Ok, maybe you could advise what packages to use for this simple scenario: I have two text strings with dates: s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" I need: 1) Find how many seconds are between these dates 2) Calculate the date in the middle between these dates 3) Print out all three dates in the different format, like these: 2011, 7 Dec, Wed, 10:11:00 What functions should I use to implement this? On Thu, Dec 8, 2011 at 7:13 PM, Antoine Latter wrote:

...

On Thu, Dec 8, 2011 at 9:01 AM, dokondr wrote:

...
Now, when I have managed to convert UTCTime to seconds (see code below) I got stuck trying to convert from UTCTime to CalendarTime, how to do this?

It might be easier to use 'diffUTCTime' and 'addUTCTime' instead of converting to and from POSIX seconds.

What do you need the 'CalendarTime' for? I recommend not mixing the 'time' and 'old-time' packages if you can avoid it.

If you really need to for inter-operating with some other library, it looks like you can use the 'datetime' package to convert from a UTCTime to a ClockTime, and then you can use the 'old-time' package to convert from a 'ClockTime' to a 'CalendarTime'.

Antoine

...
import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe import Data.Time.Clock.POSIX

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2 pt1 = utcTimeToPOSIXSeconds t1 -- :: UTCTime -> POSIXTime pt2 = utcTimeToPOSIXSeconds t2 pt3 = pt1 + (pt2 - pt1) / 2 t3 = posixSecondsToUTCTime pt3

t = compare t1 t2

tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time

timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p" -- timeFormat1 = "%m/%d/%Y %l:%M:%S %p"

On Thu, Dec 8, 2011 at 6:30 PM, dokondr wrote:

...
I need to parse time strings like "Wed, 07 Dec 2011 10:09:21 +0000" to a type that: 1) implements Eq, Ord 2) is numerical, so I could subtract one value from another to find the difference or interval length

To answer 1) requirement I wrote the following snippet. Yet I could not subtract UTCTime values. How can I convert them to milliseconds?

import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 t2 = fromJust $ tryParseTime s2

t = compare t1 t2

tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale

timeFormat1

...
timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time

timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p"

On Thu, Dec 8, 2011 at 6:12 PM, Erik Hesselink wrote:

...
I'm not sure if you really need ClockTime (from old-time), but if you don't, the types from the 'time' package are all parseable with `parseTime` [1].

Erik

[1]

http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-F...

...
On Thu, Dec 8, 2011 at 14:16, dokondr wrote:

...
Hi, What would be the simplest way to convert strings like "Wed, 07 Dec 2011 10:09:21 +0000" to System.Time.ClockTime ?

Thanks!

Antoine Latter

10:39 a.m.

On Thu, Dec 8, 2011 at 9:30 AM, dokondr wrote:

...

Ok, maybe you could advise what packages to use for this simple scenario:

I have two text strings with dates:

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000"

I need: 1) Find how many seconds are between these dates 2) Calculate the date in the middle between these dates

It looks like you already have 1) and 2) finished, using the 'time' package.

...

3) Print out all three dates in the different format, like these: 2011, 7 Dec, Wed, 10:11:00

If you need to convert into a specific time-zone you can use the 'utcToLocalTime' function in the 'time' package, which takes a UTCTime and a TimeZone to create a 'LocalTime'. I'm just guessing that you might want this, as your output format doesn't include time-zone information. Then for formatting, the 'Data.Time.Format' module in the 'time' package has the function 'formatTime', which uses the same sort of format string used by 'parseTime'. I hope that helps! It took me a while to find my way around the 'time' package properly. Antoine

dokondr

11:06 a.m.

On Thu, Dec 8, 2011 at 7:39 PM, Antoine Latter wrote:

...

On Thu, Dec 8, 2011 at 9:30 AM, dokondr wrote:

...
Ok, maybe you could advise what packages to use for this simple scenario:

I have two text strings with dates:

s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000"

I need: 1) Find how many seconds are between these dates 2) Calculate the date in the middle between these dates

It looks like you already have 1) and 2) finished, using the 'time' package.

...
3) Print out all three dates in the different format, like these: 2011, 7 Dec, Wed, 10:11:00

If you need to convert into a specific time-zone you can use the 'utcToLocalTime' function in the 'time' package, which takes a UTCTime and a TimeZone to create a 'LocalTime'. I'm just guessing that you might want this, as your output format doesn't include time-zone information.

Then for formatting, the 'Data.Time.Format' module in the 'time' package has the function 'formatTime', which uses the same sort of format string used by 'parseTime'.

I hope that helps! It took me a while to find my way around the 'time' package properly.

Antoine

Thanks so much for your help! I think I finally :) solved this problem: import Data.Time.Format import Data.Time.Clock import Locale import Data.Maybe import Data.Time.Clock.POSIX timeFormat1 = "%a, %d %b %Y %T %z" timeFormat2 = "%m/%e/%Y %l:%M:%S %p" s1 = "Wed, 07 Dec 2011 10:09:21 +0000" s2 = "Wed, 07 Dec 2011 10:11:00 +0000" t1 = fromJust $ tryParseTime s1 -- :: UTCTime t2 = fromJust $ tryParseTime s2 pt1 = utcTimeToPOSIXSeconds t1 -- :: POSIXTime pt2 = utcTimeToPOSIXSeconds t2 pt3 = pt1 + (pt2 - pt1) / 2 t3 = posixSecondsToUTCTime pt3 -- :: UTCTime -- formatTime :: FormatTime t => TimeLocale -> String -> t -> String s3 = formatTime defaultTimeLocale timeFormat2 t3 test = (compare t1 t2) == (compare pt1 pt2) tryParseTime :: String -> Maybe UTCTime tryParseTime timeStr = tryFormat (parseTime defaultTimeLocale timeFormat1 timeStr :: Maybe UTCTime) where tryFormat time | time == Nothing = parseTime defaultTimeLocale timeFormat2 timeStr :: Maybe UTCTime | otherwise = time

4915

Age (days ago)

4915

Last active (days ago)

List overview

Download

8 comments

3 participants

participants (3)

Antoine Latter
dokondr
Erik Hesselink

Converting string to System.Time.ClockTime

tags

participants (3)