# Tagged Questions

Questions about Mathematica's date and time functions.

284 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 ...
458 views

### How to Merge Date and Time?

Given the following time series data where row is date and column is time intervals. ...
62 views

### How to get the time when a notebook is saved and closed

I want to get the time when a notebook is created and the time when the notebook is saved and closed, that is to say, the whole time when a notebook exist. What should I do? Thank you!
382 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. ...
156 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 ...
252 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 ...
128 views

### Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
479 views

### How to create a combined bar plot with time format?

I'm not sure how to add time format to bar plots. I'd like to be able to make one bar plot for one data set and another for another data set and then combine them, but I don't know how to offset each ...
158 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: ...
89 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 ...
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, etc....
1k 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 ...
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 ...
247 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 ...
280 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 ...
263 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?
213 views

### Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
804 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 ...
169 views

I have ...
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 ...
173 views

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 ...
317 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: ...
464 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 ...
893 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. ...
348 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 ...
372 views

### Find all the last weekends in a year

In order to obtain the weekends of a year you'd use something like this: ...
426 views

### Handling holidays in financial time series

I have two lists: list1and list2, which are financial time series with only 2 variablesâ€”date and price. The problem is: these ...
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: ...
551 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]} {{...
730 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 ...
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 ...
436 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 ...
131 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, ...
133 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 ...
224 views

### Why do DateList, DateString, and AstronomicalData ignore $TimeZone? My reading of the documentation for DateList and DateString lead me to believe that both functions use ... 2answers 179 views ### Is it safe to change the value of$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 ...
226 views

### Is DateString supposed to be truncating seconds?

If I configure DateString to format dates as ISO dates with ...
503 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 ...
729 views

### Finding the intersection of two date lists

I've got two lists that look like this ...
794 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 ...
406 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 ...
312 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 ...
342 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 ...
410 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; ...
155 views

### Strange behavior of DateList when converting string

DateList experiences some strange behavior which i cannot explain. This code works fine: ...
137 views

### Working of Date[]

Date[] returns the current date of local system, Date[1] returns {2012, 11, 15, 17, 41, 0.3161629}, ...
547 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; ...
299 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 ...