3. PLEAC Julia: Dates and Times with Calendar.jl¶

PLEAC = Language Examples Alike Cookbook by Guillaume Cottenceau et al. PLEAC examples were drawn from the "Perl Cookbook" by Tom Christiansen & Nathan Torkington, published by O'Reilly, and used with the publisher's permission. They provide a nice range of examples oriented toward data munging, the type of work I tend to want to do first when learning a new language.

The Julia examples below are principally translations from the Python version

Caution¶

I'm learning as I go, so the code below probably doesn't represent best practice. Your suggestions are welcome! Please file an issue or make a pull request to the github repo.

The examples are not complete. Missing items are generally noted in comments.

In [1]:

VERSION

Out[1]:

v"0.2.0-rc4"

Libraries: ICU and Calendar, by @nolta¶

Calendar.jl builds on ICU.jl to provide an internationalized set of dates and times. It knows how to query the computer for timezone and daylight savings settings and provides parsing and formatting options and how to display dates and times in a localized format. It does require ICU binaries, complicating setup a bit.

In [2]:

using ICU
using Calendar
n=now()

Out[2]:

Dec 6, 2013, 10:16:38 AM EST

In [3]:

whos(ICU)

ICU                           Module
ICUCalendar                   DataType
ICUDateFormat                 DataType
UCAL_AM_PM                    Int32
UCAL_DATE                     Int32
UCAL_DAY_OF_WEEK              Int32
UCAL_DAY_OF_WEEK_IN_MONTH     Int32
UCAL_DAY_OF_YEAR              Int32
UCAL_DOW_LOCAL                Int32
UCAL_DST_OFFSET               Int32
UCAL_ERA                      Int32
UCAL_EXTENDED_YEAR            Int32
UCAL_HOUR                     Int32
UCAL_HOUR_OF_DAY              Int32
UCAL_IS_LEAP_MONTH            Int32
UCAL_JULIAN_DAY               Int32
UCAL_MILLISECOND              Int32
UCAL_MILLISECONDS_IN_DAY      Int32
UCAL_MINUTE                   Int32
UCAL_MONTH                    Int32
UCAL_SECOND                   Int32
UCAL_WEEK_OF_MONTH            Int32
UCAL_WEEK_OF_YEAR             Int32
UCAL_YEAR                     Int32
UCAL_YEAR_WOY                 Int32
UCAL_ZONE_OFFSET              Int32
UDAT_FULL                     Int32
UDAT_LONG                     Int32
UDAT_MEDIUM                   Int32
UDAT_NONE                     Int32
UDAT_RELATIVE                 Int32
UDAT_SHORT                    Int32
add                           Function
clear                         Function
foldcase                      Function
format                        Function
get                           Function
getDefaultTimeZone            Function
getMillis                     Function
getNow                        Function
getTimeZoneDisplayName        Function
lowercase                     Function
parse                         Function
set                           Function
setDate                       Function
setDateTime                   Function
setMillis                     Function
set_locale                    Function
titlecase                     Function
uppercase                     Function

In [4]:

ICU.getDefaultTimeZone()

Out[4]:

"America/New_York"

In [5]:

ICU.getNow() #epoch in milliseconds as a Float64

Out[5]:

1.386342999171e12

In [6]:

zcal=ICU.ICUCalendar("UTC")
dump(zcal)

ICUCalendar 
  ptr: Ptr{None} Ptr{Void} @0x00000000037b7200

In [7]:

lcal=ICU.ICUCalendar()
dump(lcal)

ICUCalendar 
  ptr: Ptr{None} Ptr{Void} @0x00000000037c4bf0

In [8]:

ICU.get(zcal, UCAL_MONTH)

Out[8]:

In [9]:

ICU.get(zcal, [UCAL_MONTH, UCAL_DATE, UCAL_YEAR, UCAL_ZONE_OFFSET, UCAL_DST_OFFSET])'

Out[9]:

1x5 Array{Int32,2}:
 11  6  2013  0  0

In [10]:

ldt = ICU.get(lcal, [UCAL_MONTH, UCAL_DATE, UCAL_YEAR, UCAL_ZONE_OFFSET, UCAL_DST_OFFSET])'

Out[10]:

1x5 Array{Int32,2}:
 11  6  2013  -18000000  0

In [11]:

# timezone offset in hours
ldt[4]/1000/3600

Out[11]:

-5.0

In [12]:

ICU.setDate(lcal, 2011, 11, 1)

In [13]:

millis = ICU.getMillis(lcal)

Out[13]:

1.320156999405e12

In [14]:

fmt=ICU.ICUDateFormat("yyyy", "UTC")

Out[14]:

ICUDateFormat(Ptr{Void} @0x00000000037c4e90)

ICU Format patterns:¶

Pattern	                          Result (in a particular locale)
=======                           ===============================
yyyy.MM.dd G 'at' HH:mm:ss zzz	  1996.07.10 AD at 15:08:56 PDT
EEE, MMM d, ''yy	              Wed, July 10, '96
h:mm a	                          12:08 PM
hh 'o''clock' a, zzzz	          12 o'clock PM, Pacific Daylight Time
K:mm a, z	                      0:00 PM, PST
yyyyy.MMMM.dd GGG hh:mm aaa	0     1996.July.10 AD 12:08 PM

w=week of year; W=week of month; d=day of month; D=day of year; c=Day of week

In [15]:

#ICU.format(ICUDateFormat, millis)
ifmt1 = ICU.format(fmt, millis)

Out[15]:

"2011"

In [16]:

ICU.getTimeZoneDisplayName(lcal)

Out[16]:

"EST"

In [17]:

whos(Calendar)

April                         Int64
August                        Int64
Calendar                      Module
CalendarDuration              DataType
CalendarTime                  DataType
CalendarTimeRange             DataType
December                      Int64
February                      Int64
FixedCalendarDuration         DataType
Friday                        Int64
January                       Int64
July                          Int64
June                          Int64
March                         Int64
May                           Int64
Monday                        Int64
November                      Int64
October                       Int64
Saturday                      Int64
September                     Int64
Sunday                        Int64
Thursday                      Int64
Tuesday                       Int64
Wednesday                     Int64
am                            Function
day                           Function
dayofweek                     Function
dayofyear                     Function
days                          Function
format                        Function
hm                            Function
hms                           Function
hour                          Function
hour12                        Function
hours                         Function
isAM                          Function
isPM                          Function
isleap                        Function
isleapyear                    Function
minute                        Function
minutes                       Function
month                         Function
months                        Function
now                           Function
parse_date                    Function
pm                            Function
second                        Function
seconds                       Function
timezone                      Function
today                         Function
tz                            Function
week                          Function
weeks                         Function
year                          Function
years                         Function
ymd                           Function
ymd_hms                       Function

In [18]:

t0=Calendar.now()

Out[18]:

Dec 6, 2013, 10:16:40 AM EST

In [19]:

t = ymd_hms(2013, 3, 10, 1, 59, 59)

Out[19]:

Mar 10, 2013, 1:59:59 AM EST

In [20]:

typeof(t)

Out[20]:

CalendarTime (constructor with 1 method)

In [21]:

t + days(2)

Out[21]:

Mar 12, 2013, 2:59:59 AM EDT

In [22]:

delta =t0-t

Out[22]:

271 days + 8 hours + 16 minutes + 40.49399999901652 seconds

In [23]:

t + delta

Out[23]:

Dec 6, 2013, 10:16:40 AM EST

In [24]:

dump(delta)

FixedCalendarDuration 
  millis: Float64 2.3444200494e10

In [25]:

s = Calendar.format("yyyy-MMMM-dd EEE HH:mm:ss x", t)

Out[25]:

"2013-March-10 Sun 01:59:59 -05"

In [26]:

 t2 = Calendar.parse("yyyy-MMMM-dd EEE HH:mm:ss V", s)

Out[26]:

Mar 10, 2013, 1:59:59 AM EST

In [27]:

timezone(t2, "UTC")

Out[27]:

Mar 10, 2013, 6:59:59 AM GMT

? isdst should be 0 or 1. How do we get it from datetime? Maybe we can ignore it for formatting?

PLEAC 3.0: Introduction¶

In [28]:

dayofyear(today())

Out[28]:

In [29]:

println("Today is day $(dayofyear(today())) of the current year.")

Today is day 340 of the current year.

In [30]:

println("Today is day $(dayofyear(today())) of $(year(today())).")

Today is day 340 of 2013.

PLEAC 3.1: Finding Today's Date¶

In [31]:

println("The date is $(today()).")

The date is Dec 6, 2013, 12:00:00 AM EST.

PLEAC 3.2: Converting DMYHMS to epoch seconds¶

In [32]:

now()

Out[32]:

Dec 6, 2013, 10:16:41 AM EST

In [33]:

epoch_dt = ymd_hms(1970,1,1,0,0,0,"UTC")

Out[33]:

Jan 1, 1970, 12:00:00 AM GMT

In [34]:

now() - epoch_dt

Out[34]:

16045 days + 15 hours + 16 minutes + 40.7039999961853 seconds

In [35]:

(now() - epoch_dt).millis

Out[35]:

1.386343000859e12

In [36]:

dt=now()

Out[36]:

Dec 6, 2013, 10:16:41 AM EST

In [37]:

dump(dt)

CalendarTime 
  millis: Float64 1.386343001702e12
  cal: ICUCalendar 
    ptr: Ptr{None} Ptr{Void} @0x000000001e4af1f0

In [38]:

dt.millis / 1000

Out[38]:

1.386343001702e9

In [39]:

function CalTime2epoch(caltime)
    return caltime.millis/1000
end

Out[39]:

CalTime2epoch (generic function with 1 method)

In [40]:

CalTime2epoch(today())

Out[40]:

1.386306000301e9

PLEAC 3.3: Converting epoch seconds to DMYHMS (CalendarTime)¶

In [41]:

epoch_dt

Out[41]:

Jan 1, 1970, 12:00:00 AM GMT

In [42]:

epoch_time = time()

Out[42]:

1.386343002607e9

In [43]:

function epoch2CalendarTime(epoch)
    epoch_dt = ymd_hms(1970,1,1,0,0,0,"UTC")
    return epoch_dt + seconds(epoch)
end

Out[43]:

epoch2CalendarTime (generic function with 1 method)

In [44]:

epoch2CalendarTime(epoch_time)

Out[44]:

Dec 6, 2013, 3:16:43 PM GMT

PLEAC 3.4: Adding to or subtracting from a date¶

In [45]:

mydate = ymd(2013,1,2)

Out[45]:

Jan 2, 2013, 12:00:00 AM EST

In [46]:

println("One day in the future is $(mydate + days(1))")

One day in the future is Jan 3, 2013, 12:00:00 AM EST

In [47]:

println("Two weeks in the past is $(mydate + weeks(-2))")

Two weeks in the past is Dec 19, 2012, 12:00:00 AM EST

In [48]:

dt2 = ymd(2013,2,14)
dt2 - mydate

Out[48]:

43 days

In [49]:

birthtime = ymd_hms(1973,1,18,3,45,50)

Out[49]:

Jan 18, 1973, 3:45:50 AM EST

In [50]:

then = birthtime + seconds(5)+minutes(17)+hours(2)+days(55)

Out[50]:

Mar 14, 1973, 6:02:55 AM EST

In [51]:

println("Then is $then")

Then is Mar 14, 1973, 6:02:55 AM EST

In [52]:

when = ymd(1973,1,18) + days(55)
println("Nat was 55 days old on $when")

Nat was 55 days old on Mar 14, 1973, 12:00:00 AM EST

PLEAC 3.5: Difference of two dates¶

Date differences are given in days as a Day

In [53]:

diff = dt2 - mydate

Out[53]:

43 days

In [54]:

dump(diff)

FixedCalendarDuration 
  millis: Float64 3.7152e9

differences are given in milliseconds as an Float64

In [55]:

dt1 = now()

Out[55]:

Dec 6, 2013, 10:16:44 AM EST

In [56]:

dt2 = now()

Out[56]:

Dec 6, 2013, 10:16:44 AM EST

In [57]:

diff_dt = dt2-dt1

Out[57]:

0.14100000000000001 seconds

In [58]:

dump(diff_dt)

FixedCalendarDuration 
  millis: Float64 141.0

Something like partition_period(date, (date parts,)) partition_period(datetime,(datetime parts,)) might be handy¶

In [59]:

bree = ymd_hms(1981,6,16,4,35,25)
nat =  ymd_hms(1973,1,18,3,45,50)

Out[59]:

Jan 18, 1973, 3:45:50 AM EST

In [60]:

dtdiff=bree-nat

Out[60]:

3070 days + 23 hours + 49 minutes + 35 seconds

In [61]:

dump(dtdiff)

FixedCalendarDuration 
  millis: Float64 2.65333775e11

In [62]:

dur2seconds(dur) = int(floor(dur.millis/1000)) 
dur2minutes(dur) = int(floor( (dur.millis/1000) / 60))
dur2hours(dur)   = int(floor( (dur.millis/1000) / 3600))
dur2days(dur)    = int(floor( (dur.millis/1000) / 86400 ))
dur2weeks(dur)   = int(floor( (dur.millis/1000) / 86400 / 7 ))

Out[62]:

dur2weeks (generic function with 1 method)

In [63]:

dur2days( dtdiff )

Out[63]:

In [64]:

println("There were $(dur2days(dtdiff)) days between Nat and Bree")

There were 3070 days between Nat and Bree

In [65]:

wks  = dur2weeks(dtdiff)
days = dur2days(dtdiff)
netdays = days - wks*7
hrs = dur2hours(dtdiff)
nethours = hrs - days*24
mins = dur2minutes(dtdiff)
netmins = mins - 60*hrs
netsecs = dur2seconds(dtdiff) - 60*mins
wks,netdays, nethours, netmins, netsecs

Out[65]:

(438,4,23,49,35)

Warning: imported binding for days overwritten in module Main

In [66]:

println("$wks weeks, $netdays days, $nethours:$netmins:$netsecs")

438 weeks, 4 days, 23:49:35

PLEAC 3.6: Day in a Week/Month/Year or Week Number¶

In [67]:

when = ymd(1981,6,16)

Out[67]:

Jun 16, 1981, 12:00:00 AM EDT

In [68]:

dayofweek(when) # = Tuesday

Out[68]:

In [69]:

year(when), month(when), day(when)

Out[69]:

(1981,6,16)

Formatted Datetime and Formatted Date

In [70]:

format("yyyy", when)

Out[70]:

"1981"

In [71]:

t = ymd_hms(2013, 3, 10, 1, 59, 59)

Out[71]:

Mar 10, 2013, 1:59:59 AM EST

In [72]:

s = format("yyyy-MMMM-dd HH:mm:ss V", t)

Out[72]:

"2013-March-10 01:59:59 usnyc"

Calendar.format() appears to have a limitation on maximum string length or maximum substitutions.¶

had to break up this format string into 2 parts

In [73]:

#strftime("Today is Day %w of the week (a %A). Day %d of the month (%B)",Datetime.today())
td = today()
#('MMMM')'", td)
format("'Today is Day ' c ' of the week (a ' eeee'). '",td)  * format("'Day' d 'of the month ('MMMM').'",td) 

Out[73]:

"Today is Day  6  of the week (a  Friday). Day 6 of the month (December)."

In [74]:

# Tuesday
#strftime("1981-06-16 was Day %w of the week (a %A). Day %d of the month (%B)",when)
format("'Today is Day ' c ' of the week (a ' eeee'). '",when)  * format("'Day' d 'of the month ('MMMM').'",when) 

Out[74]:

"Today is Day  3  of the week (a  Tuesday). Day 16 of the month (June)."

In [75]:

format("'Today is Day ' c ' of the week (a ' eeee'). Day' d 'of the month ('MMMM').'",when) 

WARNING:

BoundsError()
at In[75]:1
 in copy! at array.jl:49
 in getindex at array.jl:296

In [76]:

# day of year: 168, week of year=24
#strftime("Day %j of the year(%Y), in week %W of the year.",when)
format("'Day ' D ' of the year ('YYYY'), in week ' w 'of the year.'", when)

backtraces on your platform are often misleading or partially incorrect

Out[76]:

"Day  167  of the year (1981), in week  25 of the year."

PLEAC 3.7: Parsing Dates and Times from Strings¶

In [77]:

Calendar.parse("EEE MMM DD HH:mm:ss yyyy", "Tue Jun 16 20:18:03 1981")

Out[77]:

Jan 16, 1981, 8:18:03 PM EST

In [78]:

#time.strptime("16/6/1981", "%d/%m/%Y")
Calendar.parse("DD/M/yyyy","16/6/1981")

Out[78]:

Jan 16, 1981, 12:00:00 AM EST

PLEAC 3.8: Printing a Date¶

In [79]:

cdt = Calendar.now()
Calendar.format("'The date is 'YYYY",cdt)

Out[79]:

"The date is 2013"

In [80]:

"""The date is $(Calendar.format(" EEEE (EEE) d/MM/yyyy",cdt))"""

Out[80]:

"The date is  Friday (Fri) 6/12/2013"

In [81]:

Calendar.format("'The date is ' EEEE (EEE) d/MM/yyyy",cdt)

Out[81]:

"The date is  Friday (Fri) 6/12/2013"

PLEAC 3.9: High-Resolution Timers (in Base)¶

In [82]:

tic()

Out[82]:

0x0004e8bc673bc904

In [83]:

elapsed=toc()

elapsed time: 0.160737503 seconds

Out[83]:

0.160737503

In [84]:

# from https://github.com/JuliaLang/julia/issues/4478
function f1(n)
  sum = 0.0
  g1(k) = 1.0/k
  for i = 1:n
    sum += g1(i) 
  end
  sum
end

Out[84]:

f1 (generic function with 1 method)

In [85]:

f1(99)

Out[85]:

5.177377517639621

In [86]:

@time f1(1e6)

elapsed time: 0.115000702 seconds (48094564 bytes allocated)

Out[86]:

14.392726722864989

PLEAC 3.10: Short Sleeps (in Base)¶

In [87]:

sleep(3.1) #sleep for 4 seconds

In [88]:

@time( sleep(3.1) )

elapsed time: 3.101292537 seconds (408 bytes allocated)

PLEAC 3.11: Program hopdelta¶

will not solve

In [91]:

;ipython nbconvert 3_pleac_datetime-calendar.ipynb

[NbConvertApp] Using existing profile dir: u'C:\\Users\\keithc\\.ipython\\profile_default'
[NbConvertApp] Converting notebook 3_pleac_datetime-calendar.ipynb to html
[NbConvertApp] Support files will be in 3_pleac_datetime-calendar_files\
[NbConvertApp] Loaded template html_full.tpl
[NbConvertApp] Writing 276388 bytes to 3_pleac_datetime-calendar.html

In [ ]: