Hi folks,
At work, we're in the process of adopting Matlab's new datetime type. We're on R2019b currently. Our code previously used primarily datenums and datestr cellstrs or charvecs to represent dates. And we're running in to a couple hitches.
My first thought was to take class properties and function arguments that used to take datenums or datestrs as inputs, and slap a datetime validator on them:
classdef Foo
properties
aDate datetime
end
methods
function fcn(this, dt)
arguments
this
dt datetime
end
end
end
end
But that didn't work out, because Matlab's one-arg datetime(x) constructor interprets numeric inputs as datevecs, not datetimes. This surprised me, because I thought datetimes were more common than datevecs, and there's a more natural correspondence between datenum and datetime than datevec and datetime, because in a datenum array, each element represents a single date value, the same as in a datetime array.
The other hitch we're running in to is that the datetime(str) constructor that takes string inputs hits a try/catch in the ordinary "happy path" course of parsing dates. So if your code commonly uses datetime() to convert strings to dates, dbstop if all error becomes basically unusable in your programs.
>> dbstop if all error
>> datetime('1/1/2020')
Caught-error breakpoint was hit in @datetime/private/guessFormat>tryOneFmt at line 154. The error was:
Error using matlab.internal.datetime.createFromString
Unable to convert the text to datetime using the format 'dd-MMM-uuuu'.
154 t = createFromString(tryStr,fmt,2,tz,locale,pivot);
K>> dbquit
>> datetime('1/1/2020 01:23:45')
Caught-error breakpoint was hit in @datetime/private/guessFormat>tryOneFmt at line 154. The error was:
Error using matlab.internal.datetime.createFromString
Unable to convert the text to datetime using the format 'dd-MMM-uuuu HH:mm:ss'.
154 t = createFromString(tryStr,fmt,2,tz,locale,pivot);
K>> dbstack
> In guessFormat/tryOneFmt (line 154)
In guessFormat (line 43)
In datetime (line 632)
K>> version
ans =
'9.7.0.1319299 (R2019b) Update 5'
K>>
I ended up writing my own todatetime() function to use as a substitue for the datetime() constructor, and use that instead of argument validators. todatetime in MatlabProjectTemplate classdef foo
properties
aDate datetime
end
methods
function fcn(this, dt)
dt = todatetime(dt);
end
function this = set.aDate(this, aDate)
this.aDate = todatetime(aDate);
end
end
end
How are you all handling function signatures and class property constraints in codebases that have a mix of datetimes and datenums? What are you doing about that try/catch issue?
In your code, prior to datetime, were your date values predominantly datenums or datevecs?
