How do I know if NSString is empty?
You can check if [string length] == 0 . This will check if it’s a valid but empty string (@””) as well as if it’s nil, since calling length on nil will also return 0. There are some very rare NSStrings where this will result in a false negative (saying the string isn’t empty, when, for practical purposes, it is).
How do you find nil in Objective C?
length == 0) . object. length will return 0 if object == nil , so this test covers nil objects and strings with length 0. If you treat a string of length 0 different from a nil string, just check if object == nil .
How does Objective C handle null values?
The NULL value for Objective-C objects (type id) is nil. While NULL is used for C pointers (type void *). nil = (all lower-case) is a null pointer to an Objective-C object. Nil = (capitalized) is a null pointer to an Objective-C class.
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 |
How check Nsmutablearray is null in IOS?
- if (array == [NSNull null]) { //myarray is blank }
- if(array.count==0) { //myarray is blank }
- if(array == nil) { //my array is blank }
How do you check if a pointer is empty?
An integer literal with value zero (including 0 and any valid definition of NULL ) can be converted to any pointer type, giving a null pointer, whatever the actual representation. So p != NULL , p != 0 and p are all valid tests for a non-null pointer.
Is NSNull a Swift?
NSNull can be used in Swift, but when bridging the framework decided not to use it.