NSString isEqualToString not working

Question

determined as follows:

@interface KNBookmark : NSObject @property (nonatomic, strong) NSString *bookmarkId ; @property (nonatomic, strong) NSString *novelName ; @property (nonatomic, strong) NSString *novelId ; @property (nonatomic, strong) NSString *novelPic ; @property (nonatomic, strong) NSString *articleId ; @property (nonatomic, strong) NSString *articleTitle ; @property (nonatomic, strong) NSNumber *readRate ; @end @interface KNArticle : NSObject @property (nonatomic, strong) NSString *num ; @property (nonatomic, strong) NSString *articleId ; @property (nonatomic, strong) NSString *title ; @property (nonatomic, strong) NSString *subject ; @property (nonatomic, strong) NSString *text ; @end 

Source:

 for(int i=0;i<count;i++) { KNArticle* article=[self.novel.articles objectAtIndex:i]; NSLog(@"bookmark articleId='%@' articleId='%@'",self.bookmark.articleId,article.articleId); NSLog(@"bookmark articleId class='%@' articleId class='%@'",[self.bookmark.articleId class],[article.articleId class]); if([self.bookmark.articleId isEqualToString:article.articleId]) { NSLog(@"equal"); self.indexArticles=i; break; } else NSLog(@"not equal"); } 

The NSLog output is as follows:

 2014-07-16 22:56:14.768 novel[12685:90b] bookmark articleId='5680285' articleId='5680285' 2014-07-16 22:56:14.768 novel[12685:90b] bookmark articleId class='__NSCFString' articleId class='__NSCFNumber' 2014-07-16 22:56:14.769 novel[12685:90b] not equal 

Why does '5680295' not match '5680295'? I tried the following code:

 NSString* id1=@ "5680295"; NSString* id2=@ "5680295"; if([id1 isEqualToString:id2]) { NSLog(@"equal"); } 

The above code shows "equal", but I still don't know why?

Answer 1

As others have pointed out, the reason that isEqualToString: returns NO is likely because article.articleId not a string.

self.bookmark.articleId must be an instance of NSString as it responds to isEqualToString:

Make sure articleId is of the expected type:

 NSAssert([article.articleId isKindOfClass:[NSString class]], @"bad type in articleId");