Questions about Mathematica's date and time functions.

learn more… | top users | synonyms (3)

8
votes
3answers
448 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? ...
1
vote
0answers
38 views

Updating values in a Dataset [duplicate]

I'm starting to work with datasets. They seem like a useful addition to Mathematica. However, there's one fairly major stumbling block I can't get over. How do I update data in a dataset? I have a ...
3
votes
0answers
168 views

Memory problem in Mathematica 10

I'm having a problem with memory. I'm doing nonliner fits of several data lists to a system of differential equations. When I evaluate the "Do" cycle the memory grows with the iteration step up to my ...
4
votes
3answers
181 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 ...
0
votes
1answer
82 views

Export date with specified format

My problem is that I want use PGFplot in $\LaTeX$ to draw my graphs, which x axis is a date. Therefore the output file has to have one column "UTC time" (YYYY-MM-DD hh:mm:ss) and the second one is the ...
1
vote
2answers
61 views

TimeConstrained for Table?

Let's say that I have a function f[i] that takes quite a while to evaluate (evaluation time is different for different i) and I'd like to have as many values of ...
3
votes
2answers
128 views

Slow work of TimeSeriesWindow

I have financial data (list of time-values pairs). There are more than 13000 elements. ...
4
votes
1answer
146 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 ...
-1
votes
1answer
137 views

Plot CPU time vs iteration? [duplicate]

I would like to generate a plot of CPU time vs number of iterations. For example, if I were to calculate the solution of a system of differential equations in state-space form using the summation of ...
4
votes
1answer
339 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. ...
7
votes
3answers
494 views

Friday the 13th related tables

This code ...
6
votes
1answer
266 views

Can I automatically stop operation that is too slow?

I need to write code like this: Do operation 1, but if it takes more that 5 seconds then stop it and do operation 2. Is it possible to do this somehow without manual interruption?
1
vote
2answers
203 views

Extract data from DateListPlot, limited by PlotRange

Extracting the points from a line in a ListPlot in this answer uses points = Cases[Normal@plot, Line[pts_] :> pts, Infinity]; This works in DateListPlot ...
3
votes
3answers
81 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 ...
-6
votes
1answer
92 views

how to mean of day,month value

data={{{2006, 1, 1, 0, 0, 0.}, 326.492, {2006, 1, 1, 3, 0, 0.}, 323.08, {2006, 1, 1, 6, 0, 0.}, 314.223, {2006, 1, 1, 9, 0, 0.}, 314.361, {2006, 1, 1, 12, 0, 0.}, 322.048, {2006, 1, 1, 15, 0, ...
0
votes
1answer
95 views

Text with date, how to convert?

I use this script to recognise a date in a textfile and write the result in another file. ...
0
votes
2answers
143 views

How to partition three years of data into daily samples

I'm trying to find mean of temperature data list. The temperature data list has 3 hours steps which means I have 365*8=2920 temperature measurements per year. My data are temperatures of 13 years. ...
6
votes
1answer
133 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 ...
0
votes
2answers
281 views

Convert epoch seconds to date [duplicate]

I have got the following datetime from an API: 1395401384298 I am guessing it is in epoch miliseconds time (it should be one day in 2014) How can i convert it into a more readable String? I have been ...
2
votes
0answers
455 views

Speeding up Nonlinearmodelfit by constraining parameters?

I have a complicated parametric PDE that can be fitted to some data with NonlinearModelFit, but takes several hours to estimate the best values of the four free parameters. Currently, the code ...
2
votes
2answers
151 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 ...
6
votes
1answer
292 views

Wait / sleep miliseconds

Is there any way to make Mathematica stop for some miliseconds? I know about the Pause[] but it seems it only works with seconds.
2
votes
2answers
166 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 ...
1
vote
1answer
224 views

Splitting dates into groups in half year steps

list = DayRange[{1999, 1, 1}, {2014, 2, 6}] I want to split this list into sublists one and a half year long, moving a half year forward every time. That would ...
4
votes
4answers
269 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 ...
5
votes
4answers
440 views

How to Merge Date and Time?

Given the following time series data where row is date and column is time intervals. ...
1
vote
1answer
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!
11
votes
2answers
340 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. ...
2
votes
2answers
146 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 ...
4
votes
2answers
212 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 ...
5
votes
1answer
124 views

Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
2
votes
2answers
421 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 ...
5
votes
2answers
148 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: ...
4
votes
0answers
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 ...
11
votes
2answers
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, ...
10
votes
2answers
880 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 ...
45
votes
1answer
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 ...
3
votes
4answers
242 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 ...
11
votes
1answer
255 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 ...
3
votes
2answers
240 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
208 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
6
votes
6answers
725 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
161 views

Data format of Date including data

I have ...
19
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
169 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 ...
8
votes
2answers
290 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
424 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
830 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
329 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
366 views

Find all the last weekends in a year

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