Comparing Strings in Cocoa

by

First of all, you are using the == operator to compare two object pointers (of type NSString *). So that returns true when the pointers are the same, not when the strings have the same contents. If you wanted to compare whether two strings are the same, you should use isEqualToString: or isEqual: (isEqual: is more general as it works for all types of objects).

Second, compare: returns 0 (NSOrderSame) when they are the same, and 1 (NSOrderedDescending) when the first is greater than the second. So in fact it returns 1 only when they are different (specifically, when the first is greater than the second).

More Related Contents:

  1. Understanding NSString comparison
  2. Number of occurrences of a substring in an NSString?
  3. Search through NSString using Regular Expression
  4. Difference between NSString literals
  5. If “a == b” is false when comparing two NSString objects
  6. NSString: isEqual vs. isEqualToString
  7. Reverse NSString text
  8. NSString is integer?
  9. NSString – Convert to pure alphabet only (i.e. remove accents+punctuation)
  10. NSString instance reports its class as NSCFString
  11. How to get the width of an NSString?
  12. +[NSString stringWithString:] — what’s the point?
  13. What’s the Best Way to Shuffle an NSMutableArray?
  14. Why shouldn’t I use Objective C 2.0 accessors in init/dealloc? [closed]
  15. Objective-C: Reading a file line by line
  16. Deep copying an NSArray
  17. Check that a input to UITextField is numeric only
  18. Compiler error: “initializer element is not a compile-time constant”
  19. How to find out who called a method?
  20. Using NSPredicate to filter an NSArray based on NSDictionary keys
  21. NSString to CFStringRef and CFStringRef to NSString in ARC?
  22. What is the visibility of @synthesized instance variables?
  23. How can my app detect a change to another app’s window?
  24. Implementing -hash / -isEqual: / -isEqualTo…: for Objective-C collections
  25. How to make subscripts and superscripts using NSAttributedString?
  26. Removing duplicates from NSMutableArray
  27. Convert string to float in Objective-C
  28. How to make a smooth, rounded, volume-like OS X window with NSVisualEffectView?
  29. Class method equivalent of -respondsToSelector:
  30. Run AppleScript from Cocoa Application

Leave a Comment