swift - Why create "Implicitly Unwrapped Optionals"? -


why create "implicitly unwrapped optional" vs creating regular variable or constant. if know can unwrapped why create optional in first place? example, why this: 

let somestring : string! = "this string"

going more useful vs: 

let somestring : string = "this string"

if “optional indicate constant or variable allowed have 'no value'”, “sometimes clear program’s structure optional have value after value first set”, point of making optional in first place? if know optional going have value... doesn't make it.... not optional?

consider case of object may have nil properties while it's being constructed , configured, immutable , non-nil afterwards (nsimage treated way, though in case it's still useful mutate sometimes). implicitly unwrapped optionals clean code deal, relatively low loss of safety (as long 1 guarantee held, safe).

(edit) clear though: regular optionals preferable.


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