Swift === with nil -
Swift === with nil -
why next not work in swift?
if someobject === nil { }
you have test using == operator such as
if someobject == nil { }
i thinking === more making sure instances exact same (basically comparing pointers) , == more isequal check. think === more appropriate testing against nil, incorrect.
the documentation states:
=== or “identical to” means 2 constants or variables of class type refer same class instance.
== or “equal to” means 2 instances considered “equal” or “equivalent” in value, appropriate meaning of “equal”, defined type’s designer.”
it works expect:
var s: string? = nil s === nil // true
the caveat compare nil
, variable must able be nil
. means must optional, denoted ?
.
var s: string
not allowed nil
, hence returns false
when ===
compared nil
.
swift
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