compare - comparing nil to integer in Objective-C -

in following case string nsstring

if (string.length < 1) {     return; } 

and string turns out nil if statement still evaluate correctly because in case nil evaluates 0.

however, recommended practice (by clang or apple) , there arguments against , doing closer to:

if (!string || string.length < 1) {     return; } 

it's common like:

if (string.length) {     // string not nil , string has non-zero length } else {     // either string nil or length 0 } 

there no need, in such case, check see if string nil or not.

when string nil, end doing [nil length]. calling method on nil pointer results in value of "zero". how "zero" interpreted depends on method's return type.

primitive types appear 0. bool appears no. pointers appear nil.