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:

1. nil (all lower-case) is a null pointer to an Objective-C object.
2. Nil (capitalized) is a null pointer to an Objective-C class.
3. NULL (all caps) is a null pointer to anything else (C pointers, that is).

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.

How do I check if a string is empty in Objective C?

If you treat it is a null string like nil , then test (object. length == 0) . object. length will return 0 if object == nil , so this test covers nil objects and strings with length 0.

How do you check if a pointer is NULL?

Use Pointer Value as Condition to Check if Pointer Is NULL in C++ Null pointers are evaluated as false when they are used in logical expressions. Thus, we can put a given pointer in the if statement condition to check if it’s null.

How do I append to NSString?

The format specifier “\%@” is used to insert string values. The example below uses a combination of whitespace and \%@ format specifiers to append two strings to string1: NSString * string3 = [string1 stringByAppendingFormat:@” \%@ \%@”, string2, @”A third string.

How do I check if a value is null 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 .

Is null Objective C?

In Objective-C, there are a few different varieties of nothing: NULL , nil , Nil , and NSNull ….nil / Nil / NULL / NSNull.

How do you insert a null check?

Use “==” to check a variable’s value. If you set a variable to null with “=” then checking that the variable is equal to null would return true. variableName == null; You can also use “!= ” to check that a value is NOT equal.