Questions about Mathematica's date and time functions.

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5
votes
1answer
69 views

How to specify RegularlySampledQ TimeSeries with EndOfMonth date unit MinimumTimeIncrement?

"EndOfMonth" is date unit that can be used with date functions. When specifying a TimeSeries object with date increments you ...
6
votes
1answer
229 views

Throttle EventHandler KeyReleased

What might be the most elegant way to throttle the a,s functions triggered by an EventHandler...
4
votes
1answer
59 views

DateObject with DateFormat displays incorrectly in Dataset

DateObjects with DateFormat option appear to have the first date part truncated when displayed in a ...
0
votes
0answers
27 views

Using DatePlus with a list of dates and list of times to add

I have a list of dates such as t2 = {"2016-06-08 05:00:00", "2016-06-08 05:00:00", "2016-06-08 05:00:01"} and a list of offsets (in seconds), such as ...
5
votes
1answer
54 views
0
votes
1answer
33 views
6
votes
4answers
219 views

Getting AbsoluteTiming to display in hours, minutes, and seconds

I'm doing some extended length calculations and was wondering how I could get AbsoluteTiming to display in hours, minutes, and seconds. I googled and found nothing, ...
31
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 ...
6
votes
2answers
99 views

Speed up AbsoluteTime with string input

I have millions of strings representing dates in the form: "05-Mar-2004 10:15:00". I would like to convert these to absolute times. For example: ...
1
vote
1answer
109 views

Manipulate using DateObject

My question is about making a animiation using 'manipulate' using DateObject as parameter. I start with importing a file.txt, like: ...
4
votes
2answers
726 views

FrameTicks and GridLines in DateListPlot

I would like to know what is the best way to configure one GridLine for the hour in LightGray and another for the days in ...
8
votes
1answer
94 views

DatePlus and DayPlus perform much worse than my user-defined-function

I was debugging a function speed, and discovered that the time bottleneck was in DatePlus. I tried to change to DayPlus and get ...
4
votes
2answers
86 views

How to override DisplayForm of (mixed) time Quantity

What's the best approach to overriding DisplayForm for specific types of Quantity eg time especially w/ mixed units? Current is ...
4
votes
4answers
419 views

How to convert Dates with format 2016/03/1 to become {2016,3,1}

I have a problem to convert tide data with the form as follows. 2016/03/23,08:00,0.89,* 2016/03/23,09:00,1.41,* 2016/03/23,10:00,1.67,* 2016/03/23,11:00,1.44,* 2016/03/23,12:00,0.82,* 2016/03/23,13:...
3
votes
1answer
63 views

overlap of data

I have two individual Date lists as Date Objects: List 1 = {1 Jan 1991 9 :00 , 3 Jan 1991 11:00 ..etc } List 2 ={ 7 Jan 1991 14:00, 9 Jan 1991 15:00 ..etc} For ...
30
votes
2answers
3k 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 ...
3
votes
1answer
87 views
-1
votes
2answers
65 views

Matching timestamped data

I bet this question is a gimme for most of you guys, but I'm having a bit o' trouble figuring it out. Thanks ahead of time for your input and help. Soooo, I have two datasets where column 1 is a ...
8
votes
2answers
228 views

How to skip weekends in DateListPlot?

How to skip weekends in DateListPlot, ie, drawing 20 something data points for a month and not leaving 2 days gap between weeks? Currently DateListPlot occupied the actual number of days for a month ...
13
votes
2answers
378 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. ...
0
votes
1answer
58 views

Combining first 5 columns from CSV file into AbsoluteTime date

Thanks in advance for all your help. I need to import data from a CSV file that looks like : (easier to read in excel) I would like to convert the data into timestamps by creating a Table with 2 ...
5
votes
2answers
573 views

From a list of dates, get a list of the last date available in 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 ...
4
votes
1answer
54 views

TimelinePlot - Handling dates prior to Year Zero

Interested in Using TimelinePlot to help me understand/remember important time periods in Earth prehistory and history. Following an a simple example in the Documentation I create a TimelinePlot for ...
11
votes
3answers
1k views

Is it possible to import dates and times directly as AbsoluteTime and by pass DateLists?

Date and time calculations are quite slow so I am exploring ways to minimize the number of calculations performed. As an example: ...
7
votes
4answers
543 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; ...
3
votes
1answer
48 views

How to get DateListPlot Epilog to display shapes

The following should produced a plot with an orange outlined disc labelled "A" on the dotted line. Epilog produces the dotted line and the text label but is unable ...
2
votes
1answer
105 views

Automatic text-wrapping in labels in `TimelinePlot`

Part-related to this question and part-related to this one, I would like to make use of the new features of TimelinePlot in 10.3, but would like to incorporate some ...
3
votes
0answers
51 views

Possible Bug with DateObject

So my questions is going to be hard to duplicate because I am not sure when or why it happens. I've read here several bugs with DateObject, but none of them ...
5
votes
1answer
47 views

How to modify wrong time zone in a Date object?

How can one modify the wrong time zone in a DateObject, without a conversion? Can one manipulate the TimeZone directly without having the numerical value of the time changing?
2
votes
1answer
99 views

working hours and negative time [closed]

I have a list of TimeObjects. I want to subtract 5h from each element and if TimeObject < 5h then give a negative hour. My ...
5
votes
2answers
100 views

How can DateObject handle calender weeks

I have dates given for a TimeLinePlot. These dates are in {year,week} format. DateObject ...
6
votes
2answers
151 views

Plot time along the y-axis?

How can I plot times along the Y-axis, (with dates along the X-axis) e.g. ...
2
votes
2answers
44 views

Date Conversion Using Regular Expressions on “Incomplete” Date Formats

I have a list of dates in one of the following formats: "1999/05/12", "1999/05/", "1999//", "****//**/", "" so that a list of such dates might appear as ...
1
vote
1answer
93 views

Why do I get different results for the same input specified using natural language phrasing? [closed]

One of the comments to Stephen Wolfram's blog post on Ada Lovelace, mentioned that WolframAlpha (and verified in Mathematica as well) provided slightly different results for the question of Ada's age ...
10
votes
1answer
246 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: ...
4
votes
2answers
160 views

Finding the positions DateList dates in a range in large data set

There are similar questions to this like list search but this question is focused on finding at subset of dates in DateList format within a range of specified dates ...
7
votes
2answers
411 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 ...
1
vote
0answers
34 views

Save a Mathematica notebook evaluated [duplicate]

My notebooks can take some time to evaluate and by quitting Mathematica, I have to reevaluate every definition I've made once I restart Mathematica. Is there a way to tell Mathematica to save the ...
10
votes
1answer
184 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 ...
6
votes
3answers
159 views

EasterSunday replacement in Mathematica 10

The Calendar package, now obsolete, had functionality for "special dates", in particular EasterSunday[]. The documentation says it's been subsumed into Wolfram ...
5
votes
2answers
158 views

How to convert date string with fractional seconds to DateObject

I have a date/time string from a data file in the form "2014/01/09 07:24:36:001". I would like to convert it to a DateObject. I ...
6
votes
1answer
136 views

DateList does not output the correct time, but Date does

Bug fixed in 10.0.0+2014080602 I noticed a strange thing when trying the new astronomical data functions in Mathematica 10 on my Raspberry Pi. The Sunrise and <...
4
votes
1answer
79 views

Working with dates & times - nonatomic expression expected [closed]

Please note that I am new to Mathematica. I am endeavouring to import data from a CSV file with the first column a date and time. The import appears to work fine and returns the results I expect: <...
5
votes
3answers
95 views

How to ignore year in DateListPlot

I just upgraded to Mathematica 10, and I am trying to get the hang of the new TimeSeries data objects, which are preventing my old strategy of overlaying data from ...
6
votes
6answers
794 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 ...
4
votes
0answers
38 views

DateObject's DateFormat option has inconsistent result in TimelinePlot LabelingFunction and by direct call

I want to strip time and time zone from dates in the LabelingFunction of a TimelinePlot. I am using the ...
7
votes
1answer
616 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 ...
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 ...