Is nil the same as NULL in Ruby?
Is nil the same as NULL in Ruby?
3 Answers. Well, “nil” is the traditional name for the reified concept of “nothing” in Lisp and Smalltalk†. The word “null” is used as an adjective meaning “empty”, as in “the null list,” which is nil. Meanwhile, “null” is traditionally a pointer value in C that signifies the pointer doesn’t point to anything valid.
Is NULL Objective-C?
In Objective-C, there are a few different varieties of nothing: NULL , nil , Nil , and NSNull ….nil / Nil / NULL / NSNull.
| Symbol | Value | Meaning |
|---|---|---|
| nil | (id)0 | literal null value for Objective-C objects |
| Nil | (Class)0 | literal null value for Objective-C classes |
Is nil capitalized?
Nil (capitalized) is a null pointer to an Objective-C class. NULL (all caps) is a null pointer to anything else.
How does Objective-C handle NULL values?
Nil = (capitalized) is a null pointer to an Objective-C class. NULL = (all caps) is a null pointer to anything else (C pointers, that is). [NSNull null] = (singleton) for situations where use of nil is not possible (adding/receiving nil to/from NSArrays e.g.)
What is the most special aspect of nil?
Well, nil is a special Ruby object used to represent an “empty” or “default” value. It’s also a “falsy” value, meaning that it behaves like false when used in a conditional statement. Now: There is ONLY one nil object, with an object_id of 4 (or 8 in 64-bit Ruby), this is part of why nil is special.
How do I check if a Ruby hash is empty?
Ruby | Hash empty? function
- Syntax: Hash.empty?()
- Parameter: Hash values.
- Return: true – if no key value pair otherwise return false.
What is Nsmutablearray Objective-C?
NSArray is Objective-C’s general-purpose array type. It represents an ordered collection of objects. NSArray is immutable, so we cannot dynamically add or remove items.
How do you use nil return in a sentence?
nil return in a sentence
- Once registered, the taxpayer is required to submit monthly VAT returns either with payment, repayment or a nil return to the month following the month of business.
- I think imposing this would be a whole lot of work for nil return . (
What is a nil response?
a reply of zero to a request for a quantified reply.
How do I check if NSString is null in Objective-C?
So to check against NSNull one can either use: if ((NSNull *)getCaption == [NSNull null]) ……In Objective-C:
- nil (all lower-case) is a null pointer to an Objective-C object.
- Nil (capitalized) is a null pointer to an Objective-C class.
- NULL (all caps) is a null pointer to anything else (C pointers, that is).
Can a object be null?
A null object refers to an object without any reference or an object defined with neutral/null functionality/behavior. These null objects need to be checked to ensure that they are not null while accessing any member or invoking any methods.
What’s the difference between nil and null in Objective C?
all pointers that object has to other objects begin as nil, so it’s unnecessary to, for instance, set self. (association) = nil in init methods. In other languages, like C++, this would crash your program, but in Objective-C, invoking a method on nil returns a zero value.
What’s the difference between null and Nil pointers?
The difference is that while NULL represents zero for any pointer, nil is specific to objects (e.g., id) and Nil is specific to class pointers.
What’s the difference between nsnull and Nil?
NSNull is a class for objects that represent null. In fact, there’s only one object, namely the one returned by + [NSNull null]. It is different from nil because nil is a literal null value, i.e., it isn’t an object. The single instance of NSNull, on the other hand, is a proper object.
Is it necessary to set nsobjects to nil?
Newly- alloc ‘d NSObject s start life with their contents set to 0 . For this reason, it’s unnecessary to set an object’s non-primitive properties to nil in its initializer. Perhaps the most notable behavior of nil , however, is that it can have messages sent to it without a problem.