NCalc date operations

Question

I am using NCalc in a project. Is there a way to do date operations like

#16/02/2013# - #15/02/2013# = 1

I can't seem to be able to produce a result.

Expression.Evaluate();

Results is null for the above expression. I can compare two dates, but is there a way to do operations on them using NCalc?

score 8 · Answer 1 · answered Jan 21 '15 at 11:52

8

You can do this in ncalc quite easily if you are happy to create a custom function.

Expression e = new Expression("DayDiff(#16/02/2013#, #15/02/2013#)");
e.EvaluateFunction += delegate(string name, FunctionArgs args)
{
    if (name == "DayDiff")
    {
        var date1 = args.Parameters[0].Evaluate();
        var date2 = args.Parameters[1].Evaluate();
        var timespan = date2 - date1;
        return timespan.TotalDays; // double (you can convert to int if you wish a whole number!)
    }
}
Console.Write(e.Evaluate());

answered Jan 21 '15 at 11:52

Chris Walsh

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I think the current version requires you to return the result in `args.Result` as the EvaluateFunction is void. [link(https://github.com/sheetsync/NCalc/wiki) – Rob Von Nesselrode Jul 12 '19 at 05:00
@RobVonNesselrode, sounds about right. My answer is now four and a half years old! – Chris Walsh Jul 15 '19 at 14:39

score 3 · Accepted Answer · answered Mar 27 '13 at 14:57

3

No, the NCalc library doesn't allow to do this.

Read this related topic.

But you can do it withoud of NCalc.

Assuming that a and b are of type DateTime, (a - b).TotalDays will return the number of days.

answered Mar 27 '13 at 14:57

Ionică Bizău

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Thanks, but I'll need NCalc as I need to provide expression editing options for the end user on a GUI. Your link was really useful. – Daniel Mar 27 '13 at 17:00

score 2 · Answer 3 · answered Feb 25 '19 at 06:06

2

This is very late to the party but I have built an alternative option to NCalc called Expressive. This is available as a nuget package also.

It was originally built to match NCalcs functionality so migrating should require only a small amount of effort.

You can do a lot more date related functions:

DaysBetween(#15/02/2013#, #16/02/2013#)

answered Feb 25 '19 at 06:06

Bijington

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Not just expressive, but also quite impressive. Thanks for letting me know about your project. – Daniel Feb 26 '19 at 21:51
I like what you did there :) – Bijington Feb 26 '19 at 22:14

Michael Ross · Answer 4 · 2013-03-27T14:48:55.687

-1

    DateTime Date1, Date2;
    Date1 = DateTime.Parse("2013-03-27 8:42:00");
    Date2 = DateTime.Parse("2013-03-27 8:42:26");
    TimeSpan TimeSpan1 = Date2 - Date1;
    double DayDifference = TimeSpan1.TotalDays;

edited Mar 27 '13 at 14:48

answered Mar 27 '13 at 14:42

Michael Ross

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How is it related to NCalc? – Daniel Mar 27 '13 at 14:48
It's not. It's merely subtracting dates in C#. – Michael Ross Mar 27 '13 at 14:51

NCalc date operations

4 Answers4