Questions about Mathematica's date and time functions.

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5
votes
2answers
440 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
101 views

How to speed up Min of DateObjects?

I'm in version 10.0.1 using a Dataset to do some plots and things. For one of the plots I need to get the minimum date of a some filtered set of the ...
5
votes
2answers
134 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
172 views

DateList's aggressive interpretation of TimeML duration codes

DateList "aggressively" interprets strings, such as "p72h": DateList["p72h"] gives ...
5
votes
4answers
248 views

Change string date/time to be understandable for mathematica

I'm trying to convert a string of a data and time to be understandable for mathematica (I want to make time related plots). However, I can get my head around how to do this. For example: ...
5
votes
1answer
115 views

Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
5
votes
1answer
561 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 ...
5
votes
1answer
84 views
5
votes
1answer
71 views

How to remove the TimeZone from a TimeObject

TimeObject constructor adds TimeZone even when it's not meaningful or appropriate. In this example, Mathematica imputes ...
5
votes
1answer
86 views

ChineseLunar calendar system mystery

I tried to make a custom holiday calendar for the Korean Stock Exchange. And I found that the built-in "ChineseLunar" calendar system gives me an awkward result. The code is ...
4
votes
4answers
187 views

Extract Specific Dates from DateList

Hopefully this is an easy question but I couldn't find an easy answer anyway. Surely there is some simple way to splice this... I want to take a large datelist in the format of {{2014,12,31}, value} ...
4
votes
2answers
2k views

No weekends please

I need to get the DateValues of the last 30 days (starting from yesterday, not today!) excluding saturdays and sundays. I want that the dates are german time (GMT ...
4
votes
1answer
103 views

Poor (network) performance of Interpreter[“Time”]

I was surprised to see that Interpreter requires external WR resources as this is not documented, at least not here. On a 3Ghz iMac, took ~half a minute to ...
4
votes
2answers
180 views

How to change start and end date of DateListPlot with Manipulate?

Let's say I have a one dimension list d with length L. The $x$-axis in the plot starts from ...
4
votes
2answers
84 views

How to sum values in the list that belongs to same week

I need to sum values that belongs to same week. For example, I have the list x with one column and n rows. Format: ...
4
votes
3answers
175 views

How to get a list of days from July 4th to Oct 4th over a range of years

I'd like to create a list with days from the 4th of July to the 4th of October starting in July 1970 to the current date. I tried to use DateRange, but I'm a bit ...
4
votes
2answers
338 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 ...
4
votes
1answer
114 views

DateList does not output the correct time, but Date does

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
131 views

Strange behavior of DateList when converting string

DateList experiences some strange behavior which i cannot explain. This code works fine: ...
4
votes
1answer
68 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 ...
4
votes
1answer
189 views

Is DateString supposed to be truncating seconds?

If I configure DateString to format dates as ISO dates with ...
4
votes
2answers
87 views

SetOptions for CoordinatesToolOptions for DateListPlot?

DateListPlot does not respect my Options setting for CoordinatesToolOptions: ...
4
votes
0answers
58 views

Is it possible to specify GMT as default in OpenSQLConnection or JDBC?

I'm connecting to a PostgreSQL database, with tables containing TIMESTAMPs with timezone, using ...
4
votes
0answers
86 views

JewishNewYear date limitation

The documentation for the function "JewishNewYear" in the "calendar" package declares that the year argument must be between 1900 and 2100. No explanation is given for this limitation. The function ...
3
votes
4answers
232 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
3answers
128 views

Converting between AbsoluteTime and Unix time

By trial and error, I've found that the following gives the current Unix time: AbsoluteTime[] - UPOCH where UPOCH can be defined in any of the following ways: ...
3
votes
3answers
294 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 ...
3
votes
4answers
232 views

Finding the location of the last day of the month in a list of dates

My question differs from earlier questions about getting the eom dates from a list; I want to get the position of those dates so I can get the corresponding values from other lists. My problem seems ...
3
votes
2answers
169 views

Time Zone Conversion

I use Mathematica to administer my share depots. The depots contain shares of many different time zones. I update the depot values several times a day. My problem is that Sidney, Australia, (it might ...
3
votes
2answers
120 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 ...
3
votes
3answers
123 views

Get the complement date range

Suppose that I have a date range list drlist = {{"2015-01-01", "2015-01-05"}, {"2015-01-07", "2015-01-07"}, {"2015-01-12", "2015-01-23"}} ...
3
votes
3answers
74 views

Alternatives to DateQ of Calendar Package

This answer notes that Calendar package has a function DateQ but the documentation suggests that the input is limited to a fixed ...
3
votes
2answers
56 views

Make a time IntervalSlider

I want to make a time interval slider with an initial setting of (10:00:00 Mar. 8 2015, 12:30:00 Mar. 8 2015) and which varies from 00:00:00 Mar. 8 2015 to 22:30:00 Mar. 8 2015 with a granularity of ...
3
votes
2answers
117 views

Slow work of TimeSeriesWindow

I have financial data (list of time-values pairs). There are more than 13000 elements. ...
3
votes
2answers
213 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?
3
votes
2answers
56 views

AbsoluteTime parse two different date formats

I have a series of dates that regularly change format (24 hrs/12 hrs). Is there an easy way to parse this data? ...
3
votes
2answers
258 views

Should we invest in Apple?

Ticker[comp_String] := Interpreter["Company"][comp] /. Entity[_, x_] :> x ticks = Ticker /@ {"Apple", "Google"} {"NASDAQ:AAPL", "NASDAQ:GOOGL"} ...
3
votes
1answer
230 views

BarChart that lines up with dates in DateListPlot

I am trying to create a chart similar to the view offered by TradingChart, but with custom data not relating to finance. ...
3
votes
0answers
35 views

DateObject for current date skips a day when crossing the date line with TimeZone

The DateObject was introduced in version 10 of Mathematica. One can call it to fetch the current local date and time: ...
2
votes
4answers
191 views

How to remove hours, minutes, seconds from list

How to remove 0 that represent hours, minutes, and seconds from a date list say a ...
2
votes
2answers
107 views

I'm trying to filter a date range by day of month and day of week - what am I doing wrong?

I am trying to generate a list of dates that match two criteria: they have to all be the first of the month, and they have to be a particular day of the week, Sunday in my case. The code I have ...
2
votes
2answers
118 views

Converting a date to a calendar quarter

I have a list that includes dates. I need to convert each date to be the last day of the quarter that it's in. So for example I want {2013,7,1,0,0,0} to become {2013,9,30,0,0,0}. Actually I don't ...
2
votes
2answers
369 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; ...
2
votes
2answers
305 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
120 views

Counting Events in a moving date range

I want to count the number of times events take place in a date range. The counting is done over a window of e.g. 28 days where the goal is to have between 11 and 13 events in the time window. The ...
2
votes
1answer
40 views

DateValue returns inconsistent types

More of a 'why' than a 'how' question... DateValue[{2014,4,12},"DayName"] returns Saturday, a symbol rather than the string "Saturday". Every other result that ...
2
votes
1answer
137 views

A possible bug with regard to DateObjects in Version 10?

Bug related to the Suggestion Bar Bug While getting used to the new data type Date Object in Version 10 I noted that there seems to be a bug which on my machine ...
2
votes
1answer
148 views

DateListPlot with multiple data sets and incongruous timelines?

I am using Mathematica to analyze some sales data for my company. (A copy of the available data is here.) We are trying to analyze the sales trends for each month by item. DateListPlot works well ...
2
votes
1answer
187 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
2
votes
1answer
83 views

Correct handling of milliseconds in a date time string

DateString[{2014, 5, 7, 13, 47, 44.760}, {"Year", "-", "Month", "-", "Day", " ", "Hour", ":", "Minute", ":", "Second", ".", "Millisecond"}] Returns ...