Questions about Mathematica's date and time functions.

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40
votes
1answer
938 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 ...
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
0answers
609 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 ...
22
votes
3answers
871 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 ...
20
votes
3answers
1k 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.
18
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
9answers
1k 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 ...
13
votes
3answers
1k 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 This package now appears to be out of date; but as near as I can tell, many of the useful ...
12
votes
5answers
971 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
546 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 ...
12
votes
4answers
328 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 ...
12
votes
2answers
358 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
1answer
228 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 ...
11
votes
7answers
217 views

DateList coupled with String Operations

Through some webscraping, I have the following list: ...
10
votes
2answers
268 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
2answers
492 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
1answer
480 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
191 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
1answer
206 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
330 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
207 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. ...
9
votes
1answer
241 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 ...
9
votes
1answer
112 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. ...
8
votes
3answers
317 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
212 views

How to do DateDifference on table items containing dates

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

Faster Alternatives to DateDifference

I need a faster implementation of FractionOfYear and FractionOfMonth, which do the following: Input: A time/date specified by ...
8
votes
2answers
179 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
223 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
152 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. ...
7
votes
3answers
465 views

Friday the 13th related tables

This code ...
7
votes
3answers
174 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
3answers
406 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
3answers
321 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
138 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
455 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 ...
6
votes
2answers
1k 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, ...
6
votes
5answers
363 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 ...
6
votes
3answers
268 views

Importing and manipulating strings - time data

I have a list of time durations, which are strings of the form: "hh:mm:ss". Here's a sample for you to play with: ...
6
votes
2answers
200 views

DateList Segmentation of data

I've been trying to separate large segments of DateList formatted data (years worth at a time) into individual days using the Split function. The data has the form: ...
6
votes
2answers
215 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: ...
6
votes
3answers
170 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.") ...
6
votes
3answers
253 views

Determining the dates of days

I'm trying to use WeatherData[] to give me (not sure how) the temperature, humidity, wind-speed, cloud cover... at a certain location. I only want the information ...
6
votes
5answers
329 views

Handling holidays in financial time series

I have two lists: list1and list2, which are financial time series with only 2 variables—date and price. The problem is: these ...
6
votes
1answer
94 views

How to make several DateListPlot have the same scale?

I want to plot some weather data series. Unfortunately the series were collected in different episodes, from which some overlap. I would like to plot them as different plots in a column, but with ...
6
votes
2answers
578 views

Select elements of list within a date range

I have a list which consists of elements each of which has a date in DateList format, a number and a flag (Y/N). e.g. ...
5
votes
2answers
538 views

Finding the intersection of two date lists

I've got two lists that look like this ...
5
votes
4answers
381 views

How to Merge Date and Time?

Given the following time series data where row is date and column is time intervals. ...
5
votes
2answers
392 views

From a list of dates get a list of the last date available in a each month

I wondered if anyone has another or even a more direct way of finding the last dates of each month available from a list of successive dates? I currently do the following (note: nothing special about ...
5
votes
2answers
131 views

How can AbsoluteTimes be split by date faster?

I have data where the date is stored as an AbsoluteTime. Here's a dummy dataset: ...
5
votes
3answers
171 views

DateList's aggressive interpretation of TimeML duration codes

DateList "aggressively" interprets strings, such as "p72h": DateList["p72h"] gives ...