将字符串切割成数组 componentsSeparatedByString

- (void)viewDidLoad

{

    NSString *a = [[NSString alloc] initWithString : @"冬瓜，西瓜，火龙果，大头，小狗" ];

    NSArray *b = [a componentsSeparatedByString:@"，"];

    NSString *a3 = [b objectAtIndex:2];

    NSLog(@"   b的第三个东东是： %@", a3);

    [a release];

}