1 00:00:00,190 --> 00:00:02,536 The next design patterns we're going to discuss, are 2 00:00:02,536 --> 00:00:06,630 summarization patterns. And, these are patterns that give you, some 3 00:00:06,630 --> 00:00:10,145 quick easy high level understanding of your data. And we're 4 00:00:10,145 --> 00:00:12,530 going to make a distinction here. We're going to talk about making 5 00:00:12,530 --> 00:00:16,050 what's called an inverted index. And this is very similar 6 00:00:16,050 --> 00:00:17,760 to the index you'd find in a back of a 7 00:00:17,760 --> 00:00:21,840 book, or the indexing that Google does when it crawls 8 00:00:21,840 --> 00:00:25,990 the web. And, we're also going to talk about numerical summarizations. 9 00:00:27,050 --> 00:00:32,600 And, these are things like finding counts, how many of a certain record type, or 10 00:00:32,600 --> 00:00:37,980 min and max. And min and max of course, can be used to calculate first 11 00:00:37,980 --> 00:00:42,140 or last. Or calculate statistics like, mean 12 00:00:42,140 --> 00:00:46,600 and median, and basically any other high level 13 00:00:46,600 --> 00:00:48,660 numerical value that you can use to summarize 14 00:00:48,660 --> 00:00:52,084 your data set. In this section of summarization 15 00:00:52,084 --> 00:00:54,493 patterns, we'll also talk about some 16 00:00:54,493 --> 00:00:58,727 interesting additional [INAUDIBLE] functionality, something that 17 00:00:58,727 --> 00:01:01,574 can exist between [INAUDIBLE] reducers, known 18 00:01:01,574 --> 00:01:03,330 as combiners. So, let's keep going.