null (2024)

FAQs

Should I ever return null? ›

If you return null then you have to make sure that the callers of the method properly handle the null. This trap will eventually lead to an NPE at some point. Optionals are a good way to avoid the NPE. You can also use exceptions or a hybrid of exceptions and optionals depending on your use case.

Coined by Sir Tony Hoare, the very inventor of the null reference, the term is not merely a self-deprecating quip but a stark reflection of the cumulative costs associated with unforeseen bugs, crashes, and the maddening hours developers worldwide have spent debugging a null pointer exception.

Null Doesn't Trigger Default Values

If you have variables that could be indiscriminately set to either null or undefined (a situation which is very likely if you are allowing both into your application code), these default values will not always be applied as you are likely to want them to be applied.

In terms of the relational database model, a NULL value indicates an unknown value. If we widen this theoretical explanation, the NULL value points to an unknown value but this unknown value does not equivalent to a zero value or a field that contains spaces.

Null character, U+0000 <control-0000>, U+2400 ␀ SYMBOL FOR NULL (a single-character glyph "NUL")

Null is a special instruction in the language that can substitute any type. Put in another way; it means that null inherits from all reference types. Because of that, you cannot think of your code logically anymore. You always have to check if the value is of subtype null or not.

null is not an identifier for a property of the global object, like undefined can be. Instead, null expresses a lack of identification, indicating that a variable points to no object. In APIs, null is often retrieved in a place where an object can be expected but no object is relevant.

To sum up: If you have any nulls in your database, then you're getting wrong answers to certain of your queries. What's more, you have no way of knowing, of course, just which queries you're getting wrong answers to and which not; all results become suspect.

In 2009, Tony Hoare stated that he invented the null reference in 1965 as part of the ALGOL W language. In that 2009 reference Hoare describes his invention as a "billion-dollar mistake": I call it my billion-dollar mistake. It was the invention of the null reference in 1965.

Null values appear in both statically and dynamically typed languages. In statically typed languages they break the type system beyond repair. In dynamically typed languages they are an expensive crutch for bad design. And their existence cannot be properly reasoned by how computer is doing pointer arithmetic.

Why do people use null? ›

null is a pointer that doesn't refer to a valid object. This is similar to saying that null points to nothing. Or, in simpler words: null is nothing. For example, if we consider a linked list, in which every item in the list keeps a pointer to the next one, null is used to mark the end of the list.

A quick definition of null:

For example, if a contract is declared null, it means it is no longer legally enforceable. The phrase "null and void" means the same thing and is often used together.

The Disadvantages of NULL

The first one is that NULL is considered a variable-length value. This means that it could be a few bytes or several bytes. The database leaves room for extra bytes should the value be larger than what is stored in the field.

In a database, zero is a value which has meaning, so the value NULL became is a special marker to mean that no value exists. In that sense, NULL does not refer to a memory location, as it does for programming languages.

The null sign (∅) is often used in mathematics for denoting the empty set. The same letter in linguistics represents zero, the lack of an element.

The answer to that is rather simple: a NULL means that there is no value, we're looking at a blank/empty cell, and 0 means the value itself is 0. Considering there is a difference between NULL and 0, the way Tableau treats these two values therefore is different as well.

A "nullnull" text message typically indicates that there was an issue or error in the transmission or processing of the message. In technical terms, "null" refers to a lack of value or an empty space, and when repeated as "nullnull," it signifies a specific error code or placeholder.

If you get this error because you've used a space character between ranges that don't intersect, change the references so that ranges do intersect. For example, in the formula =CELL(“address”,(A1:A5 C1:C3)), the ranges A1:A5 and C1:C3 don't intersect, and the formula returns the #NULL! error.

A: Although they may seem similar and are sometimes used interchangeably, it's generally better to use them for their intended purposes. Use null when you want to represent the intentional absence of a value, and undefined when a variable has not been assigned a value.

If your method returns null collections, this can lead to potential errors. The calling code must handle the null case and check for null before accessing any collection elements. You need to add a null-check every time that can clutter the calling code and make it harder to read.

Is it better to return undefined or null? ›

if you do something like need to check "is it already has something? (and must know is it checked or not)" so you can go with null appoarch (to check the case when variable was assigned already? and check between null and undefined ). otherwise, if you not serious on this, undefined is good to go.

When a function returns null , the caller has to handle the possibility of a null value, which can complicate the code and make it harder to understand. This can lead to more bugs and more difficult debugging.

Returning empty lists or arrays instead of null can help you write code that's safer and easier to understand. It eliminates the risk of NullReferenceException when the returned value is used and makes it clear that the method didn't find anything to return.