pod 'DYSafeObject', '~> 0.1.1'

pod update

NSString *s1 = nil; NSArray *array = @[s1,@"a",@"v",@"c",@"d",@"f",@"s",@"v",@"g"]; NSMutableArray *mutableArray = [[NSMutableArray alloc] initWithArray:array]; NSLog(@"数组 Test--array:%@ mutableArray:%@",array[20],mutableArray[20]); NSLog(@"数组 Test--array:%@ mutableArray:%@",[array objectAtIndex:20],mutableArray[20]); NSLog(@"数组 Test--array%@",array);

NSString *key = nil; NSString *str = nil; NSDictionary *dict = @{key:str}; NSArray *dArray = @[str]; NSMutableDictionary *mutableDict = [NSMutableDictionary dictionary]; mutableDict[@"key"] = str; NSLog(@"字典 Test--dict:%@",dict); NSLog(@"字典 Test--dArray:%@",dArray); NSLog(@"字典 Test--mutableDict:%@ key:%@",mutableDict,mutableDict[@"key"]);

NSMutableString *string = [[NSMutableString alloc] initWithFormat:@"世界因我而精彩"]; NSLog(@"字符串 Test--%@",[string substringFromIndex:50]);

NSDictionary *dic2 = @{@"key":[NSNull null]}; NSLog(@"dic2==%@",dic2); [dic2[@"key"] UTF8String];