In Kotlin, by default the variables var is of non-null type.
If you really want to allow type to accept 'null' values, you must explicitly states so as below using '?' operator.
Please do not misinform readers, it not by default and definitely not an '?' operator. (Operators cannot be applied to types). It's part of type system where '?' in the end of type denotes reference as nullable and without - non-null references. Here's proper explanation of nullability in Kotlin.
Actually nullability-related operators are ?., !!., ?: and as?.
"Please do not misinform readers" That's harsh. He didn't do it intentionally. As he mentioned, he's currently learning the language himself. Why are you being intentionally rude then?
Agreed. That's harsh!. Anyway, String? is actually syntactic sugar for something like Nullable<String>. It's an idea taken from Maybe polymorphic data type, which is very popular in Functional Languages like Haskell.
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Please do not misinform readers, it not
by defaultand definitely not an'?' operator. (Operators cannot be applied to types). It's part of type system where '?' in the end of type denotes reference as nullable and without - non-null references.Here's proper explanation of nullability in Kotlin.
Actually nullability-related operators are
?.,!!.,?:andas?.Thank you Vladislav Rassokhin for the feedback. I have updated the blog as per the comments.
"Please do not misinform readers" That's harsh. He didn't do it intentionally. As he mentioned, he's currently learning the language himself. Why are you being intentionally rude then?
Agreed. That's harsh!. Anyway,
String?is actually syntactic sugar for something likeNullable<String>. It's an idea taken fromMaybepolymorphic data type, which is very popular in Functional Languages like Haskell.