WEBVTT 00:01.060 --> 00:07.420 Programming often involves examining a set of conditions and deciding which action to take based on 00:07.420 --> 00:08.440 these conditions. 00:08.470 --> 00:15.580 Python's If statement allows you to examine the current state of a program and respond appropriately 00:15.580 --> 00:16.510 to that state. 00:16.540 --> 00:22.660 In this section, you will learn to write conditional tests which allow you to check any condition of 00:22.660 --> 00:27.970 interest, and you will learn to write simple if statements and you will learn how to create a more 00:27.970 --> 00:35.320 complex series of if statements to identify when the exact conditions you want are present, and you 00:35.320 --> 00:41.410 will then apply this concept to lists and so you will be able to write a for loop that handles most 00:41.410 --> 00:47.070 items in a list one way, but handles certain items in a with specific values in different way. 00:47.080 --> 00:57.440 So this example here we will show the if tests that let you respond to special situations correctly. 00:57.460 --> 01:02.810 Imagine you have a list of cars and you want to print out the name of each car. 01:02.810 --> 01:04.910 So car names are proper names. 01:04.910 --> 01:09.440 So the names of most cars will be printed in title names title case. 01:09.470 --> 01:16.160 However, the value BMW here should be printed in all uppercase and here we will. 01:16.160 --> 01:17.900 Which we will do that right now. 01:17.900 --> 01:23.120 So we will car makers, car makers here. 01:23.120 --> 01:25.130 And after that we will equal to. 01:25.160 --> 01:33.680 So first we will enter the Volkswagen, the BMW, the Toyota, Toyota. 01:37.020 --> 01:37.710 Port. 01:38.650 --> 01:39.430 And. 01:41.760 --> 01:49.740 And here we will use the four car in car makers and here. 01:49.740 --> 02:02.430 So if car equals to BMW, then we will print the car dot upper and else here we will. 02:02.460 --> 02:07.650 Else we will print the car dot title. 02:07.650 --> 02:08.550 That's it. 02:08.550 --> 02:10.500 So now let's run it. 02:10.890 --> 02:11.460 That's it. 02:11.460 --> 02:12.090 Here. 02:12.360 --> 02:12.680 Oops. 02:13.050 --> 02:17.820 If BMW oops if BMW, that's it. 02:18.180 --> 02:20.130 Now this will work here. 02:21.450 --> 02:24.240 So now the loop in this example. 02:24.240 --> 02:25.260 First checks. 02:25.260 --> 02:32.460 If the current value of a car, if the current value of a car is BMW. 02:33.760 --> 02:39.440 If it is, the value is printed in uppercase here with this function. 02:39.460 --> 02:40.030 Right. 02:40.300 --> 02:47.050 If the value of a car is anything other than a BMW, it is printed in a title case. 02:47.170 --> 02:49.840 And here this is our output here. 02:50.020 --> 02:58.000 All of these names are written in title case, but here BMW is written in uppercase. 02:58.000 --> 03:02.730 So this example combines the number of concepts you will learn about in this section. 03:02.740 --> 03:09.220 Let's begin by looking at the kinds of tests you can use to examine the conditions in your program, 03:09.220 --> 03:12.850 so we can also use conditional tests in Python. 03:12.850 --> 03:18.820 So at the heart of every if statement is an expression that can be evaluated as true. 03:19.060 --> 03:20.800 As true. 03:22.630 --> 03:24.460 Or false, Right? 03:29.990 --> 03:41.630 So Python uses the values true and false to decide to decide whether the code is in a if statement should 03:41.630 --> 03:42.950 be executed or not. 03:42.980 --> 03:46.550 So if a conditional test evaluates true. 03:47.470 --> 03:52.240 Then Python executes the code following the if statement. 03:52.240 --> 03:54.550 So if the test evaluates false. 03:54.910 --> 03:58.540 If python ignores the code following the if statement. 03:58.930 --> 04:00.490 We can also check for equality. 04:00.490 --> 04:06.130 So the most conditional test compare the current value of a variable to a specific value of interest. 04:06.130 --> 04:13.990 So the simplest conditional test check test checks whether the value of a variable is equal to the value 04:13.990 --> 04:14.860 of interest. 04:14.890 --> 04:20.350 In order to do that, we will just delete for now our for loop and we will print here. 04:20.740 --> 04:25.870 Now car equals BMW here. 04:26.050 --> 04:31.120 Or let's actually, instead of writing that, let's use car makers. 04:31.120 --> 04:36.370 BMW index is one BMW and BMW here. 04:36.610 --> 04:41.740 So now as you can see we got an error cannot assign to a function call. 04:41.740 --> 04:46.480 So here that is we're going to get an error if we try to do that. 04:46.480 --> 04:50.960 However, if you try this in Python console, which we will now. 04:52.850 --> 04:53.270 Here. 04:53.270 --> 04:54.650 We opened our python. 04:54.650 --> 04:59.090 Now you can reach this by using just python. 05:00.900 --> 05:05.070 And here you're going to see this python 64 bit or 32 bit. 05:05.100 --> 05:09.450 You just enter that and here you can see the new tab opened. 05:09.480 --> 05:12.050 Here, let's actually make it closer. 05:12.060 --> 05:13.290 So most conditional. 05:13.290 --> 05:17.940 Let's ah, compare the current value of a variable to a specific value of interest. 05:17.970 --> 05:22.170 Let's create a new value named car here and make it BMW. 05:22.410 --> 05:26.850 And after that we will check the is car equal to BMW. 05:26.880 --> 05:30.730 And here you can you can see we got true. 05:30.750 --> 05:34.530 So the first line here actually, let me get this. 05:34.530 --> 05:38.010 So this first line, let me fix this. 05:38.040 --> 05:41.190 Now here, this first line here. 05:42.330 --> 05:44.250 Sets the value of a car. 05:44.890 --> 05:51.880 Car sets the value of a car to be actual b m. 05:51.880 --> 05:52.840 W. 05:54.320 --> 05:56.720 Using a single equal sign. 05:56.720 --> 06:00.860 So here we use the single equal sign here. 06:00.860 --> 06:01.460 Right? 06:02.860 --> 06:05.770 As you've seen many times already, this sign. 06:05.770 --> 06:12.460 So the next line checks the whether the value of a cars is BMW. 06:12.490 --> 06:14.590 Here you see here. 06:16.000 --> 06:16.950 Of sexual issues. 06:16.960 --> 06:18.310 Different color here. 06:21.540 --> 06:27.630 So now we are checking this by using a double equal sign. 06:28.170 --> 06:30.360 Double equal sign. 06:32.120 --> 06:32.660 Here. 06:33.020 --> 06:34.010 Car. 06:35.450 --> 06:36.280 Is. 06:37.700 --> 06:38.540 We? 06:39.440 --> 06:40.940 And W. 06:42.150 --> 06:46.830 So this is the equality operator. 06:46.950 --> 06:54.090 So and so this equality operator here, this is this is named equality Operator. 06:54.090 --> 06:57.150 Let me actually write that here. 06:57.180 --> 06:59.880 This is equality. 07:06.160 --> 07:07.120 Operator. 07:12.950 --> 07:18.710 So here this equality operator returns true, like in this case. 07:19.780 --> 07:25.030 If the values on the left and the right side of the operator match in this case, these are match. 07:25.030 --> 07:28.420 So car is actually equals to BMW. 07:28.450 --> 07:30.400 Actually, let me use the different color. 07:30.400 --> 07:35.500 So here our car is equals to BMW here. 07:36.480 --> 07:39.240 Because we already assign that in first line. 07:39.240 --> 07:43.410 And our BMW here equals to BMW, Right. 07:43.800 --> 07:52.500 So we are checking this BMW W and here they match. 07:52.530 --> 07:55.710 In this case, they will return. 07:55.740 --> 07:56.490 True. 07:58.310 --> 07:59.150 That's it. 07:59.570 --> 08:02.600 But here the values in this example. 08:02.600 --> 08:03.500 Match. 08:03.500 --> 08:04.160 Match. 08:04.160 --> 08:06.830 So Python returns true. 08:07.130 --> 08:15.380 So when the value of a car is anything other than a BMW, for example, let's try car equals equal the 08:15.620 --> 08:27.590 jeep here we will get false if car equal equal uppercase B M-W We will get false again because these 08:27.590 --> 08:34.580 equations equalization equation equality operator are case sensitive in strings. 08:34.580 --> 08:42.830 So here if we try something ice cream, ice cream, we will get false again. 08:43.450 --> 08:44.290 So. 08:45.450 --> 08:47.910 That's it here with operator. 08:47.910 --> 08:51.150 So a single equal sign is really a statement. 08:51.150 --> 08:58.410 And you might read the first line of a code here that we are setting a set the value of a car equal 08:58.410 --> 08:59.010 to. 09:00.440 --> 09:00.670 It. 09:00.860 --> 09:07.100 For example, Jeep, on the other hand, a double equal sign ask asks a question. 09:07.100 --> 09:08.900 Let me actually write it down. 09:09.200 --> 09:13.760 Some new programmers might confuse this with equate initialization. 09:14.970 --> 09:15.560 Here. 09:15.570 --> 09:19.530 So this this double equal. 09:19.740 --> 09:23.970 Double equal signs asks the Or. 09:27.830 --> 09:30.200 Here asks this. 09:32.250 --> 09:35.130 I get this text here, this ask this. 09:35.130 --> 09:39.960 So is the value of car. 09:40.960 --> 09:44.040 Equal to BMW. 09:45.140 --> 09:47.030 So here our. 09:49.130 --> 09:51.650 W equate equality. 09:51.860 --> 10:00.920 W equal sign asks whether value of this value of a car or a car in this case in is variable, right? 10:01.130 --> 10:10.730 Because we use this car as a variable name and here is the value of car equal to BMW. 10:10.730 --> 10:12.170 In this case it's equal. 10:12.170 --> 10:14.480 So it will return. 10:14.480 --> 10:15.230 True.