WEBVTT 00:00.150 --> 00:00.840 All right. 00:00.900 --> 00:07.320 So we're moving onto logical order which as I just mentioned is like a brother or sister to a logical 00:07.350 --> 00:07.850 end. 00:07.980 --> 00:14.820 And if you've worked with any programming language you're most likely familiar with and and or logical 00:14.820 --> 00:21.420 and and logical or so logical or you can either write out as Omar or just like we could write A&E for 00:21.420 --> 00:24.880 and or we can use these two pipe symbols. 00:24.960 --> 00:32.040 So these are not uppercase eyes or els or ones they are the piped character which is usually located 00:32.250 --> 00:35.090 above the right return or enter key. 00:35.100 --> 00:38.420 You have to hit shift most often to hit it. 00:38.550 --> 00:44.190 So it's two of them together just like it was two ampersands for and just symbols. 00:44.190 --> 00:49.780 It's pretty standardized or very standardized across all program languages that I've worked in ampersands 00:49.860 --> 00:51.630 and types for or. 00:51.810 --> 00:56.180 But you can also use the phonetic or that spelt that version o r. 00:56.340 --> 01:00.690 So before we dive into exactly how it works let's try something. 01:00.690 --> 01:02.610 So we had this in the last video. 01:02.670 --> 01:05.310 So it's all books written by Dave Eggers. 01:05.460 --> 01:07.780 Released after the year 2010. 01:08.280 --> 01:13.750 But what if we just change the ampersands to the or pipes. 01:13.950 --> 01:15.470 What do you think will happen first of all. 01:15.480 --> 01:19.590 So I'm just going to copy this an Oxford type this all again. 01:21.730 --> 01:28.150 And just change the ampersands here to OR and make a hit return. 01:28.150 --> 01:30.820 So it's clear what's happening. 01:30.820 --> 01:36.640 So if we read this if you just say the word or hear it makes a bit more sense it's like title An author 01:36.640 --> 01:44.240 name and released year from books where author name is Aggers or released here is greater than 2010. 01:45.310 --> 01:55.090 So if we run it what we'll get is all books written by Dave Eggers and all books were released here 01:55.240 --> 01:56.780 is greater than 2010. 01:57.220 --> 02:03.220 So rather than both sides of this having to be true just if either side is true we'll get the data so 02:03.220 --> 02:09.640 we get all the books by Eggers including this one a heartbreaking work a staggering genius which came 02:09.640 --> 02:17.200 before 2010 but then we move on to the second part which is to selected all books that were released 02:17.230 --> 02:20.440 after 2010 regardless of the author's name. 02:20.950 --> 02:25.810 So it's a way for us to specify two things either of which we want to be true or both. 02:25.960 --> 02:32.680 So in the case of a hologram for the king it is both written by Dave Eggers and it was released after 02:32.800 --> 02:37.090 2010 or same thing with the circle here. 02:37.630 --> 02:43.420 But 10 percent happier for instance it was only this part was true released years greater than 2010 02:43.690 --> 02:48.240 because author L name is Harris or Saunders In this case or gaming. 02:48.670 --> 02:52.040 OK so again that symbol right there. 02:52.320 --> 02:57.620 I forgot I made this nice little slide this animation that changes symbol is very very important. 02:57.640 --> 03:01.490 It changes the meaning entirely from the statement. 03:01.600 --> 03:07.120 So if we have two conditions with an ampersand between them or three or any number of conditions with 03:07.120 --> 03:12.790 ampersands it means that both sides must be true in order for the whole thing to be true as we've seen 03:12.790 --> 03:14.110 already. 03:14.140 --> 03:21.730 However with the OR operator it means only one side must be true for the whole thing to be true or both 03:21.730 --> 03:22.910 sides can be true as well. 03:22.930 --> 03:27.480 And I know that's a bit odd to talk about in this way without actual examples. 03:27.670 --> 03:32.350 So if we hop over again and we do the same thing I've been doing the last couple of videos and to type 03:32.350 --> 03:36.310 up a few example exercises and then we'll go over solutions. 03:36.680 --> 03:38.030 OK so I'm back here. 03:38.220 --> 03:44.920 I've got three just three this time that I'll use logical order to try them out and then I'll be back 03:44.920 --> 03:47.660 with a solution and I'm back already. 03:47.800 --> 03:48.370 OK. 03:48.480 --> 03:50.000 So first one here. 03:50.330 --> 03:51.220 40. 03:51.250 --> 03:53.340 Less than or equal to 100. 03:53.710 --> 03:55.400 Well that part's true. 03:55.730 --> 03:57.150 Forty is less than 100. 03:57.190 --> 03:59.020 So it doesn't matter what's over here. 03:59.020 --> 04:03.750 This whole thing is true because we only need one half to be true. 04:03.970 --> 04:13.680 Happens that negative 2 is not greater than zero but that's irrelevant because the left side is true. 04:13.690 --> 04:17.370 Moving on to this one 10 and greater than five is that true. 04:17.440 --> 04:19.040 Yes. 04:19.180 --> 04:20.970 So it doesn't matter what's on the right side. 04:20.980 --> 04:26.830 But that happens to also be true that the whole thing is true. 04:27.040 --> 04:33.520 So we get one and this last one bit of a curve ball is the letter A. 04:33.520 --> 04:35.210 Equal to the number five. 04:35.290 --> 04:36.460 Well that's not true. 04:37.270 --> 04:40.430 However this side says 3000 is greater than 2000. 04:40.450 --> 04:41.310 That is true. 04:41.320 --> 04:42.400 So the whole thing is true 04:45.400 --> 04:47.690 as you can see we get one for true. 04:48.130 --> 04:48.760 OK. 04:49.000 --> 04:50.220 Last thing before I forget. 04:50.230 --> 04:50.820 Just like with. 04:50.830 --> 04:54.190 And we can chain or together as many times we want. 04:54.190 --> 04:56.350 So it doesn't have to be something like this. 04:56.380 --> 05:04.420 So if I go back to this example it's like title author I'll name released your from books where author 05:04.420 --> 05:07.120 name is Aggers or release here is greater than 2010. 05:07.180 --> 05:10.960 So let's try adding an OR here and I'll spell it out this time. 05:10.960 --> 05:17.740 And let's say not only do we care or do we want to select things written by Eggers or released or greater 05:17.740 --> 05:18.630 than 2010. 05:18.640 --> 05:25.420 We'll also add another or which is stock quantity is greater than 100. 05:25.570 --> 05:28.460 So books that we have a lot of stock in as well. 05:28.510 --> 05:36.050 And let's also print stock quantity just like that just copy this whole thing. 05:36.200 --> 05:38.550 Paste it semi-colon. 05:39.050 --> 05:46.240 And if we look to see it makes a slight difference because we also get this. 05:46.250 --> 05:52.400 David Foster Wallace story collection in here which was written in 2004 which normally wouldn't make 05:52.400 --> 05:56.790 the cut with our previous version but because we added star quantity greater than 100. 05:57.110 --> 06:00.610 It's in here because stuck on the is greater than 172. 06:00.680 --> 06:03.780 So for some of these for instance a hologram for the king. 06:04.040 --> 06:05.460 All three parts are true. 06:05.690 --> 06:11.180 It's written by Aggers it's released after 2010 and it has more than 100 copies in stock. 06:11.360 --> 06:16.330 But then like for David Foster Wallace and oblivion only one part is true. 06:16.430 --> 06:17.120 The last part. 06:17.300 --> 06:22.580 So it just goes to show you that only one component even if we have three different conditions only 06:22.580 --> 06:26.000 one part has to be true for the entire thing to be true. 06:26.090 --> 06:29.780 And for it to be selected and spit back to us OK. 06:30.120 --> 06:36.210 So that's logical or one thing that I will point out that I know you're probably dying to get on with 06:36.210 --> 06:40.790 this video but you can combine or and and see how to do that in a little bit.