My dictionary is always nil, would like to understand why this is happening. My code:
var dic = [NSDate : MCACalendar]?() dic?[currentDate!] = calendar 
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2 Answers
@Kirsteins provides the solution - but it's good to know why.
Using [NSDate : MCACalendar]?() doesn't work as you expect because it creates an instance of [NSDate : MCACalendar]?, i.e. an instance of an optional - to be more precise, an instance of Optional<[NSDate : MCACalendar]>. So that initialization doesn't create an instance of [NSDate : MCACalendar].
Creating an instance of an optional (Optional<T>) using the parameterless constructor initializes it to .None (equivalent to nil), so for example in:
var x = Int?() // `x` is initialized as `.None` If a parameter is passed to the constructor, then the optional variable is initialized with .Some:
var x = Int?(5) // x is initialized as `.Some(5)` That explains Kirsteins's solution no. 1. Solution no. 2 is so obvious that it doesn't need further explanation :)
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It seems [NSDate : MCACalendar]?() fails and returns nil. You probably want to use:
var dic = [NSDate : MCACalendar]?([:]) or
var dic: [NSDate : MCACalendar]? = [:] 
4 Comments
diogo.
I got the error: "fatal error: unexpectedly found nil while unwrapping an Optional value"
Kirsteins
As error states you unwrapped something that is
nil. What was the line that was crashing?diogo.
the line: "tempDic?[currentDate!] = calendar"
Kirsteins
I guess that
currentDate is nil.