2019年2月16日 · It can be used on a type to control Nullability, it is then called the "Null Forgiving Operator". Basically, null! applies the ! operator to the value null. This overrides the nullability …

2009年12月4日 · The expression "NULL = NULL" evaluates to NULL, but is actually invalid in SQL; yet ORDER BY treats NULLs as equal (whatever they precede or follow "regular" values …

2015年10月2日 · Null não é um tipo nessas linguagens, e também não significa ausência de tipo. Ele pode ser um tipo em outras. null == null e é diferente de todo o resto (nestas linguagens). …

2023年9月11日 · Cuál es la diferencia en JavaScript entre una variable undefined y una variable null? cómo puedo saber si una variable está null, undefined o ambos? también quisiera saber …

2021年9月21日 · The only difference (besides the syntax) is, that the compiler guarantees that no user-overloaded operator is called when using is not null instead of != null (or is null instead of …

In Java I am told that when doing a null check one should use == instead of .equals(). What are the reasons for this?

The rules for == and != explicitly include a clause that stipulates that null and undefined are the same. Personally — that is, in my code — that fact is a reason for using != (or ==) when …

And then == null does a perfect job, because it covers exactly those 2 values. (i.e. == null is equivalent to === null && === undefined) In exceptional cases you do want a clear distinction …

2011年4月14日 · 135 NULL has no value, and so cannot be compared using the scalar value operators. In other words, no value can ever be equal to (or not equal to) NULL because NULL …

2009年4月29日 · The surprise expressed by JavaScript developers at typeof null === "object" is the result of an impedance mismatch (or abstraction leak) between a weakly-typed language …