Questions about Mathematica's date and time functions.

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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, ...
4
votes
1answer
413 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 ...
40
votes
1answer
947 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 ...
3
votes
4answers
229 views

Test whether date is in a certain period

I have one table which contains time periods ("start" and "end") and a "type" for every ...
3
votes
2answers
192 views

WeatherData for the 15th day of each month

Suppose we have WeatherData["Helsinki", "MeanTemperature", {{2007, 1, 1}, {2012, 12, 31}, "Day"}] How we can have data just for 15th day of each month?
2
votes
1answer
174 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
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 ...
1
vote
4answers
138 views

Data format of Date including data

I have ...
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 ...
2
votes
1answer
149 views

ReadList importing negative times

This is probably an easy question to answer, but I need a fresh eye... I'm struggling with processing the following file (extract shown here) It's a list of dates, and positive/negative time durations ...
6
votes
2answers
217 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: ...
4
votes
2answers
280 views

Can Mathematica understand Excel dates when in number format?

I have a very large Excel file with dates in the format 2013/01/17 08:02:00 PM which is a custom date format. I have to convert this file to CSV in order to import it into Mathematica because I can't ...
6
votes
2answers
582 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. ...
3
votes
3answers
269 views

How to paint part of DateListPlot?

My graph is about fires (burned area) over 12 years presented in one Date List Log Plot. Because most of fires are in summer (as expected) I would like to highlight that with different background ...
7
votes
3answers
322 views

Find all the last weekends in a year

In order to obtain the weekends of a year you'd use something like this: ...
6
votes
5answers
332 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 ...
12
votes
5answers
977 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: ...
1
vote
1answer
342 views

Converting Excel serial dates with NETLink

Excel serial dates are not straightforward to convert since they include non-existent dates, e.g. {DatePlus[{1990, 1, 0}, 59], DatePlus[{1990, 1, 0}, 60]} ...
22
votes
3answers
873 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 ...
-1
votes
1answer
321 views

Importing Quicken Tab Delimited .*TXT File and plotting

I am using Mathematica 7 to try and plot my quicken data file. I have exported my quicken file as a .*TXT and have made zero changes to it. I want to do a ...
0
votes
1answer
122 views

Changing Datelist order

Im wondering how can I formulate a function which receives input in the string format "day.month.year hours: minutes: seconds" (for example, ...
3
votes
2answers
115 views

Is there a faster way to compute the endpoint for a DateRange given the start, step, and length?

Say I am given a date start an increment step (possibly mixed radix) and a desired number of steps ...
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 ...
2
votes
1answer
91 views

Is it safe to change the value of $TimeZone?

I'd like to configure some of my notebooks to assume all calculations using dates, times and locations (notably AstronomicalData , but others too) take place at the ...
4
votes
1answer
176 views

Is DateString supposed to be truncating seconds?

If I configure DateString to format dates as ISO dates with ...
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 ...
5
votes
2answers
538 views

Finding the intersection of two date lists

I've got two lists that look like this ...
26
votes
0answers
612 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 ...
12
votes
2answers
359 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
229 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 ...
2
votes
2answers
290 views

How do I generate a 3d histogram of runs

This question is an extension of the question I asked here Histogram of runs. What I would like to do now is generate a Histogram3D that has the run duration on the x axis and the mean level on the ...
2
votes
2answers
356 views

Histogram of runs

What I would like to do is generate a histogram of the consecutive time spent under a level. For example if the level I was interested in was 1.0 and I had this data; ...
4
votes
1answer
126 views

Strange behavior of DateList when converting string

DateList experiences some strange behavior which i cannot explain. This code works fine: ...
1
vote
1answer
121 views

Working of Date[]

Date[] returns the current date of local system, Date[1] returns {2012, 11, 15, 17, 41, 0.3161629}, ...
7
votes
3answers
407 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; ...
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 ...
9
votes
1answer
242 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 ...
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.
12
votes
3answers
549 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 ...
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 ...
6
votes
3answers
269 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: ...
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 ...
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: ...
5
votes
1answer
505 views

Simple countdown timer in Mathematica

I dug around a bit and did not find a simple and clear implementation of countdown stopwatch in Mathematica. I am looking for a function that takes as an input a certain integer and then counts down ...
1
vote
1answer
224 views

How can Time be made to go backwards?

I would like to make a countdown timer, but cannot find a reliable method to make the DateList[] function reverse. The not so robust code for the Digital Clock with the display of seconds follows: ...
11
votes
7answers
218 views

DateList coupled with String Operations

Through some webscraping, I have the following list: ...
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 ...
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. ...
5
votes
3answers
171 views

DateList's aggressive interpretation of TimeML duration codes

DateList "aggressively" interprets strings, such as "p72h": DateList["p72h"] gives ...
9
votes
1answer
334 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 ...