Questions about Mathematica's date and time functions.

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45
votes
1answer
2k views

How can I manipulate TemporalData?

Version 9 introduced TemporalData but, truth be told, the documentation doesn't suggest that one can do much with it. Many of us have probably assumed we'd be ...
30
votes
1answer
780 views

What calendar is Mathematica using for dates in the distant past?

It appears that Mathematica treats all dates as proleptic Gregorian dates by default, a hypothesis that can be easily tested by using AbsoluteTime to compute the ...
26
votes
6answers
1k views

Faster alternatives for DayOfWeek

It has been noticed on several occasions that DayOfWeek function is rather slow when applied to a large list of dates, e.g. in this recent question. What faster ...
26
votes
4answers
1k views

Does Mathematica have a built-in date picker?

Does Mathematica have an interactive date input control that lets the user choose a date by browsing to a calendar view and returning the selected date as a date list? For example, something like the ...
23
votes
3answers
4k views

how to make graphic timelines in mathematica

Hi does anyone know how to make timelines with mathematica? Something like that would be great!
21
votes
3answers
2k views

How can I make a heatmap of a days in year?

I know Mathematica has a ListPlot for time series but does it have a function for visualizing a list of dates as a heat map like this: This idea is from D3, check it out here.
19
votes
1answer
1k views

The Orbit and Perigee of the Flamsteed comet

Historical context This year we have the 330-th anniversary of the Battle of Vienna - one of the great formative events of European history, it took place on September 12, 1683. Kara Mustafa, Grand ...
17
votes
10answers
2k views

Determining the week of a year from a given date

Consider the following: AbsoluteTime["17/04/2012",{"Day","/","Month","Year"}]; From my calendar in my office, I know that April 17th is in the 16th week of the ...
14
votes
3answers
280 views

Min, Max are slow on TimeObjects

fixed in 10.1 (windows) There's something wrong with how Min and Max are implemented for ...
14
votes
3answers
2k views

How do I compute sidereal time and JD?

There was once a package that provided a wide range of functions for computing astronomical information. This package now appears to be out of date; but as near as I can tell, many of the useful ...
14
votes
5answers
466 views

Does Mathematica support importing ISO 8601 date strings?

Does Mathematica have a built-in function to convert ISO 8601 formatted date strings (e.g. 2012-01-04T00:00:00) to a date list? ISO 8601 strings come in a variety ...
14
votes
1answer
295 views

Is there a way to get AbsoluteTime to correctly report absolute time differences?

Absolute time supposedly reports the "total number of seconds" between two dates, but it does not. For example because of the leap second applied at 2012-06-30T23:59:60Z ...
13
votes
4answers
361 views

How to evaluate the second argument of Cases only once

I'd like to find a fast but readable way to achieve the following: ...
13
votes
2answers
401 views

How is AstronomicalData interpreting its date arguments?

It is easy to confirm that the AstronomicalData is not interpreting its arguments as UTC (or "GMT", which is, in any case, ambiguous) dates by verifying that the ...
12
votes
5answers
2k views

Sort date list in format DD/MM/YYYY

I have a list of dates (ranging from 2007 to 2012) in the DD/MM/YYYY format and I need to sort this list. My problem is, when I simply use Sort[] I get: ...
12
votes
3answers
815 views

Simpler way to fill date gaps with zero values

One basic problem when working with data like sales and dates is the case where you dont't have sales in all days, so you have to fill it to take information as average or to make a plot. See this toy ...
11
votes
7answers
246 views

DateList coupled with String Operations

Through some webscraping, I have the following list: ...
11
votes
2answers
3k views

Measuring execution time of code

How one can measure the execution time (time that is spent for code to finish) of a program in Mathematica? I understand that there are general timing functions (Timing, AbsoluteTiming, TimeUsed, ...
11
votes
2answers
340 views

ScheduledTask with scoped variables. Working with timed evaluation

I guess I have to try harder and focus more but timed evaluation always frustrates me. I will show the issue on simple example of delayed trigger. ...
11
votes
1answer
255 views

TimeConstrained dynamic change of maximum time

I would like to run a time consuming function: TimeConstrained[f[x],maxseconds] and be able to change maxseconds during running (increasing or decreasing max ...
10
votes
1answer
177 views

DateDifference isn't consistent when giving result in years

This isn't really causing me a problem at the moment, but it's weird. Is this documented anywhere? When I ask for the difference in days and then in years between April 1, 2015 and October 1, 2015 ...
10
votes
2answers
295 views

Approaches For Creating Cycle Plots in Mathematica

I am trying to create a cycle plot in Mathematica, and I am having a hard time finding the right approach to create the visualization. Can anyone give me a few pointers as to how to approach the ...
10
votes
3answers
740 views

MovingAverage[] and Fit[] with data containing DateLists

I have data which has the following appearance: data = {{DateList, Real}, ..., {DateList, Real}} It's easy to visualize the data by using ...
10
votes
2answers
880 views

UNIX time to DateList

I have data that is timestamped with UNIX time, which is the number of seconds since January 1, 1970 UTC. Unfortunately, it seems that most of the date and time functions in Mathematica are based on ...
10
votes
1answer
634 views

How to import date (YYYY-MM-DD) data from a file?

I have a file with data in form {date, value}: 2010-05-19 17 2010-05-20 20 ...
10
votes
1answer
232 views

Behavior of TimelinePlot with multiple datasets of associations

Bug introduced in 10.1 and fixed in 10.3 The following TimelinePlot behaves as I would expect: ...
10
votes
1answer
115 views

DateList not using current year when a year is not specified

According to the documentation when using DateList but not giving it a year it should use the current year. It is not doing that for me. Instead it uses 1900. ...
10
votes
1answer
210 views

Why do DateList, DateString, and AstronomicalData ignore $TimeZone?

My reading of the documentation for DateList and DateString lead me to believe that both functions use ...
9
votes
5answers
476 views

Calendar view outline

How to compute the outline of a calendar month like this D3 example. (D3 is a functional language built on JavaScript developed at Stanford and used by New York Times to deploy interactive ...
9
votes
3answers
375 views

Faster Alternatives to DateDifference

I need a faster implementation of FractionOfYear and FractionOfMonth, which do the following: Input: A time/date specified by ...
9
votes
1answer
260 views

How can I convert the dates returned by FinancialData into decimal representation?

I'm trying to run a regression using Fit on the output of FinancialData["SPY", "Jan. 1, 2011"]. However, the dates returned ...
9
votes
1answer
477 views

How can I get the frame ticks from DateListPlot?

DateListPlot very nicely chooses major and minor frame tick and frame tick label/markers. I am building a custom graphics function where either the ...
9
votes
1answer
281 views

How do I determine astronomical transit times?

Mathematica, through the "legacy" Scientific Astronomer package, used to have the ability to easily determine accurate transit times of astronomical objects simply, with ...
8
votes
3answers
448 views

Does Mathematica have Month Range and Day range?

It is known that CharacterRange["a", "z"] gives list of characters from a to z. Does Mathematica have something similar for weekdays and months of the year? ...
8
votes
5answers
229 views

How to do DateDifference on table items containing dates

I have a Table with data in form {{date}, value}: ...
8
votes
3answers
331 views

Timeline plotting: horizontal bars of time intervals

This text file logs the time that a process (identified by a number) changes state ("Brown", "Blue" etc.") ...
8
votes
2answers
290 views

How can this AbsoluteTime call be made faster?

I need to convert tons of date strings into absolute times. This generates an example data set of 10,000 strings: ...
8
votes
2answers
346 views

interpolating function over dates

I've got a bunch of readings at various dates and times. I'd like to be able to interpolate and then integrate over, say days. I can do this by converting my date/time to ...
8
votes
1answer
246 views

Day of the week vs time on BoxWhiskerChart

I am completely stuck on how to approach this problem: I'm basically trying to figure out when is the best time to tweet on twitter, based on a list of timestamps: Here are the raw values: ...
8
votes
1answer
196 views

Bug in DateListPlot in Mathematica 10

Mentioned this already in an answer to a related question. DateListPlot in Mathematica 10 has a horrible bug: If two points have the same time coordinate, only one is plotted; the others are ignored. ...
8
votes
2answers
179 views

SetOptions for CoordinatesToolOptions for DateListPlot?

Bug introduced in 10.0 and persisting through 10.2.0 or later DateListPlot does not respect my Options setting for ...
7
votes
3answers
494 views

Friday the 13th related tables

This code ...
7
votes
2answers
338 views

How much time should one give Mathematica for an integral evaluation?

Sometimes when I do integrals in Mathematica (M), it keeps thinking and thinking and I have no idea what is going on inside M. For how long should one wait or how does one know whether M has not got ...
7
votes
4answers
515 views

Filter list based on date

What I would like to do is remove entries from a list of instrument data when it is in maintenance. The maintenance data I have is a series of dates which look like this; ...
7
votes
1answer
609 views

Why does Mathematica's date for the battle Agincourt differ from the US Navy's?

If I ask Mathematica for the Julian Date for the battle of Agincourt with WolframAlpha["battle of agincourt date"] it reports ...
7
votes
3answers
218 views

Different results with DateRange and LeapYearsQ in Mathematica 9 and 10

With Mathematica 9.0 for Mac OS X x86 (64-bit) (January 24, 2013) one could use DateRange[{2000}, {2010}, "Year"] to achive ...
7
votes
1answer
154 views

Determining FinancialData for Countries

How do I determine the FinancialData for Australia. For instance the one for USA follows as: FinancialData["NYSE", "Members"] ...
7
votes
3answers
366 views

Find all the last weekends in a year

In order to obtain the weekends of a year you'd use something like this: ...
7
votes
2answers
151 views

DatePlus and DateList are inconsistent with numerical handling of the final element

If you run this code you will see that DatePlus and DateList are inconsistent in the format of the lowest order element of the ...
6
votes
6answers
725 views

Sort list by day names (Monday, Tuesday, etc)

I have some dates in a list, and I want to plot how many of those dates are Monday, Tuesday, etc. I'm using this: data = {...} Tally[DayOfWeek /@ data] and I ...