WEBVTT 00:00.140 --> 00:00.710 Hello guys. 00:00.710 --> 00:03.110 So we are going to continue the discussion with respect to Python. 00:03.110 --> 00:06.380 And in this video we are going to discuss about variables okay. 00:06.410 --> 00:08.030 Now what exactly is variables. 00:08.030 --> 00:10.730 And here I have also given the entire video outline. 00:10.730 --> 00:15.560 So we will first of all introduce or like the topic is introduction to variables. 00:15.560 --> 00:18.230 Then we'll be seeing how we can declare and assign variables. 00:18.230 --> 00:20.180 Then we'll talk about the naming convention. 00:20.180 --> 00:21.890 Then we'll understand variable type. 00:21.920 --> 00:24.620 We'll see type checking and conversion dynamic typing. 00:24.620 --> 00:28.220 And finally we'll be seeing a lot of practical examples and common errors okay. 00:28.250 --> 00:31.700 So all these things will be specifically covered in this video okay. 00:31.730 --> 00:34.700 Now first of all as usual let's go with the definition. 00:34.700 --> 00:39.470 So variables are fundamental elements in programming used to store data that can be referenced and manipulated 00:39.470 --> 00:40.310 in a program. 00:40.310 --> 00:46.730 In Python, variables are created when you assign a value to them, and they do not need explicit declaration 00:46.730 --> 00:48.410 to resolve memory space. 00:48.410 --> 00:52.310 The declaration happens automatically when you assign a value to a variable. 00:52.340 --> 00:57.530 Okay, so the best way to give you an example is that let's say if I define a is equal to 100. 00:57.530 --> 00:59.240 So this basically becomes the variable. 00:59.240 --> 01:04.100 And always remember guys whenever you start a new notebook file, always make sure to select the kernel. 01:04.130 --> 01:04.520 Okay. 01:04.550 --> 01:06.410 Now if I'm going to write a is equal to 100. 01:06.440 --> 01:10.790 This basically means that I've created a variable a and I've assigned a value to 100. 01:10.820 --> 01:11.390 Okay. 01:11.570 --> 01:16.700 Now uh, obviously in my previous video I've also defined some basic variables and all and I've assigned 01:16.700 --> 01:21.470 some values, let's say string, numerical uh, integers, floating point, anything, any values you 01:21.470 --> 01:22.820 can basically assign. 01:23.180 --> 01:24.680 Uh, we'll be learning more about it. 01:24.710 --> 01:34.340 Uh, so first of all, let's go ahead and understanding about declaring, declaring and assigning variables 01:34.370 --> 01:34.970 okay. 01:35.360 --> 01:40.100 So here you'll be able to see that uh, let's say I'm going to define age is equal to 32. 01:40.130 --> 01:45.530 I'm going to probably define height is equal to six feet or 6.1. 01:45.560 --> 01:47.060 That is specifically my height. 01:47.060 --> 01:48.110 So I'm writing it down. 01:48.110 --> 01:49.670 So height is equal to 6.1. 01:49.700 --> 01:53.840 Then let's say name is equal to my name I will go ahead and define crush. 01:54.170 --> 01:58.760 Uh and then here you can also see that I can also define a Boolean variable. 01:58.760 --> 02:02.230 Let's say I will go ahead and define is underscore student. 02:02.260 --> 02:02.620 Okay. 02:02.650 --> 02:04.690 I will also talk about naming convention. 02:04.780 --> 02:07.090 What is the best naming convention of defining a variable. 02:07.090 --> 02:08.350 What are the good practices. 02:08.350 --> 02:09.790 Everything I'll be discussing about. 02:09.790 --> 02:12.910 So let's say I'm going to define a boolean variable as true right. 02:12.940 --> 02:15.730 We'll learn more about the specific data types in my next video. 02:15.730 --> 02:17.710 But here I'm just giving you an example okay. 02:17.740 --> 02:19.030 So h is equal to 32. 02:19.060 --> 02:19.990 This this is there. 02:19.990 --> 02:21.940 And I have actually written it right now. 02:21.940 --> 02:24.010 Let me quickly go ahead and print it. 02:24.010 --> 02:26.290 And this is how we assign a variable right. 02:26.320 --> 02:29.260 We are declaring a variable and assigning some values right. 02:29.260 --> 02:34.330 So now let me just go ahead and print printing the variables. 02:34.330 --> 02:34.810 Right. 02:34.810 --> 02:36.220 So here you can see. 02:36.220 --> 02:39.790 So now first of all I'm going to print H right. 02:39.790 --> 02:45.730 And this is where I will also show you how you can use different print, how you can display in your 02:45.730 --> 02:46.720 console in a different way. 02:46.720 --> 02:52.480 So first of all let's say I want to print h so h colon let's say I want to assign this h colon with 02:52.480 --> 02:53.440 some value over here. 02:53.440 --> 02:55.690 So I will go ahead and define my variable h right. 02:55.720 --> 03:01.000 Similarly, if I go ahead and show you the next print statement here, I'm going to basically write 03:01.030 --> 03:01.960 height. 03:01.990 --> 03:02.530 Okay. 03:02.530 --> 03:06.070 And with respect to this particular height I am going to define another variable. 03:06.070 --> 03:08.140 Let's say this will basically be my height. 03:08.320 --> 03:12.220 Another next thing that I'm going to print over here is my name. 03:12.250 --> 03:17.080 And here you can probably see that I'm going to basically define my name. 03:17.080 --> 03:19.060 And let me just go ahead and write comma. 03:19.060 --> 03:20.770 And this will basically be my name. 03:20.800 --> 03:21.220 Right. 03:21.250 --> 03:25.600 So if I want to define all these things you here, you can see I'm displaying age is equal to 32. 03:25.630 --> 03:26.980 Height is equal to 6.1. 03:27.010 --> 03:28.000 Name is equal to crush. 03:28.030 --> 03:32.530 That basically means see when I'm printing I can also call this particular variable that I have actually 03:32.530 --> 03:33.490 defined okay. 03:33.550 --> 03:35.140 So these are some of the ways. 03:35.170 --> 03:40.630 Again we will be discussing about more different boolean type more different data types as we go ahead. 03:40.630 --> 03:43.210 And that is how we declare different different variables. 03:43.210 --> 03:47.020 But just a basic idea for you with respect to the variable declaration. 03:47.050 --> 03:47.560 Okay. 03:47.920 --> 03:51.190 Now coming to the next one, which is basically called as naming convention. 03:51.190 --> 03:52.810 And this is the most important one. 03:52.810 --> 03:55.000 Like how should we name a variable. 03:55.030 --> 03:55.600 Right. 03:56.050 --> 03:59.020 And for this you really need to know about the naming convention. 03:59.770 --> 04:03.370 Some of the important points that I would like to mention over here. 04:03.400 --> 04:06.370 Let's say a variable's name, right? 04:06.400 --> 04:14.620 The variable name that we define right should be should be descriptive. 04:15.130 --> 04:15.700 Okay. 04:15.760 --> 04:24.610 Then uh, the second point that I would like to mention they must always start with a letter. 04:24.640 --> 04:24.880 Okay. 04:24.910 --> 04:26.350 So this is the second condition. 04:26.380 --> 04:29.260 Or it can also start with an underscore. 04:29.290 --> 04:29.740 Okay. 04:29.770 --> 04:33.190 Underscore like underscore uh this kind of underscore mark. 04:33.190 --> 04:33.730 Right. 04:33.760 --> 04:42.820 And uh, it can contain letters numbers and underscore in between. 04:42.820 --> 04:43.450 Right. 04:43.900 --> 04:44.680 In between. 04:44.680 --> 04:49.240 But always understand they must always start with a letter or underscore. 04:49.240 --> 04:52.540 And it can contain letters, numbers and underscores. 04:52.570 --> 04:52.750 Okay. 04:52.780 --> 04:54.340 Within inside that okay. 04:55.540 --> 04:57.010 And uh, one more thing. 04:57.010 --> 04:59.390 Very important point, which I have already mentioned. 04:59.390 --> 05:04.580 Variables names are case sensitive. 05:05.120 --> 05:05.660 Okay. 05:05.690 --> 05:06.950 This also I have defined it. 05:06.950 --> 05:08.660 So these are some of the naming important. 05:08.690 --> 05:10.700 Naming convention with respect to the variables. 05:10.730 --> 05:11.210 Okay. 05:11.240 --> 05:13.610 Now let's see some kind of example over here. 05:13.640 --> 05:17.690 So first of all I will just go ahead and write some valid variable name. 05:17.720 --> 05:17.960 Okay. 05:17.990 --> 05:20.210 So valid variable names. 05:20.210 --> 05:25.790 So first valid variable name I'm going to define it as first underscore name is equal to crush. 05:25.820 --> 05:26.450 Okay. 05:26.780 --> 05:30.560 Uh last underscore name is equal to Nayak. 05:30.560 --> 05:30.860 Right. 05:30.860 --> 05:34.190 So is this a good way of writing a variable. 05:34.190 --> 05:34.640 Yes. 05:34.670 --> 05:35.960 Does it start with a letter? 05:35.990 --> 05:36.410 Yes. 05:36.410 --> 05:37.640 It starts with a letter. 05:37.670 --> 05:41.630 Does can it contain letter number or numbers or underscores? 05:41.660 --> 05:42.560 Yes, it can contain. 05:42.560 --> 05:45.560 So here you can see I am having letters or underscore. 05:45.590 --> 05:49.040 I can also put numbers in between but not in the starting right. 05:49.070 --> 05:51.770 So this is a good way of defining a variable. 05:51.800 --> 05:52.220 Okay. 05:52.220 --> 05:55.100 So here uh this absolutely works fine. 05:55.160 --> 05:58.670 Let me say show you some invalid variable name. 05:59.940 --> 06:01.740 Invalid variable names. 06:01.770 --> 06:02.310 Okay. 06:02.730 --> 06:05.610 So let's say that I define with a number. 06:05.640 --> 06:05.910 Right. 06:05.910 --> 06:08.430 And if I go ahead and define over here age is equal to 30. 06:08.460 --> 06:11.760 See I'm getting an error saying that invalid decimal literal right. 06:11.790 --> 06:13.290 So I cannot start with a letter. 06:13.290 --> 06:14.880 So this is one way okay. 06:15.030 --> 06:20.370 The another way is that, uh can I define something like this first dash name. 06:20.520 --> 06:21.030 Right. 06:21.060 --> 06:24.930 Can I define like this first dash name is equal to, let's say Krish. 06:25.440 --> 06:26.490 Can I define like this? 06:26.520 --> 06:27.480 Will I get an error? 06:27.480 --> 06:30.720 So here you can see cannot assign to expression here. 06:30.720 --> 06:34.380 Maybe you mean double equal to or instead of equal to. 06:34.410 --> 06:36.060 So this is not being considered. 06:36.060 --> 06:38.160 This symbol is also not being used. 06:38.160 --> 06:38.760 Right. 06:39.510 --> 06:43.080 Uh so obviously this is also an invalid variable name. 06:43.110 --> 06:43.770 Right. 06:43.800 --> 06:48.540 The third invalid variable name can I use at the rate and define a name variable. 06:48.570 --> 06:49.080 Right. 06:49.080 --> 06:51.210 So let me just go ahead and check it out. 06:51.210 --> 06:53.400 So here I'll just go ahead and write Krish. 06:53.430 --> 06:54.570 Will I get an error. 06:54.570 --> 06:55.950 It says invalid syntax. 06:55.950 --> 06:57.540 Maybe you meant so and so right. 06:57.540 --> 07:00.990 So this is also not a valid variable name. 07:00.990 --> 07:02.610 It is an invalid variable name. 07:02.640 --> 07:03.120 Okay. 07:03.120 --> 07:07.560 And already I have spoken about case sensitive right. 07:07.590 --> 07:08.850 Case sensitivity. 07:08.880 --> 07:09.390 Right. 07:09.420 --> 07:17.970 If I define name is equal to Krish and let's say I have defined capital name is equal to Nayak. 07:17.970 --> 07:18.420 Right. 07:18.450 --> 07:20.940 Both these are different right. 07:20.940 --> 07:21.990 It is not same. 07:22.020 --> 07:22.290 Right. 07:22.320 --> 07:27.120 If I really want to compare, can I compare like this number name double equal to capital name. 07:27.210 --> 07:29.040 It will be giving false right? 07:29.040 --> 07:29.430 Yes. 07:29.430 --> 07:30.000 The values. 07:30.000 --> 07:31.530 If it is same it will give me true. 07:31.530 --> 07:35.940 But in short you can see that these are different identifiers, right? 07:36.090 --> 07:38.790 Later on I can do the comparison operation and I can do it right. 07:38.790 --> 07:41.310 So obviously case sensitivity is also there right. 07:41.340 --> 07:45.900 So this was related to something related to the naming conventions okay. 07:45.930 --> 07:51.690 Now let me just go ahead and make you understand about some of the variable types okay. 07:51.690 --> 07:55.440 So we will continue the writing the code here itself. 07:55.440 --> 08:01.410 So let me just go ahead and write Understanding variable types. 08:01.620 --> 08:08.910 Okay, now one thing you need to understand Python is dynamically typed okay. 08:09.060 --> 08:11.400 Dynamically typed. 08:12.480 --> 08:13.710 What does this mean? 08:13.710 --> 08:16.590 This means the type of a variable. 08:17.370 --> 08:25.110 Type of a variable is determined at runtime and determined at runtime. 08:25.140 --> 08:25.680 Right. 08:25.710 --> 08:27.990 So this is very much important okay. 08:28.020 --> 08:32.700 And some of the important data types are like int float string and boolean right. 08:32.730 --> 08:35.790 So let's say if I write e is equal to 25 right. 08:36.030 --> 08:40.080 So when I execute it during the runtime it will understand. 08:40.110 --> 08:40.830 Hey fine. 08:40.830 --> 08:42.240 Integer is basically getting assigned. 08:42.270 --> 08:44.460 So age is an integer variable right. 08:44.490 --> 08:48.900 And let's say that I will go ahead and define some more variables right. 08:48.930 --> 08:50.760 Let's say height right. 08:50.790 --> 08:52.860 I'm going to basically go ahead and define height. 08:52.860 --> 08:54.600 Let's say I'm going to write 6.1. 08:54.600 --> 08:57.720 So this this is nothing but it is integer. 08:57.750 --> 08:59.940 This is nothing, but this is float. 08:59.970 --> 09:02.220 See how I'm also using the single line comments? 09:02.220 --> 09:02.700 Right? 09:02.730 --> 09:05.190 Let's say if I'm going to define my name. 09:05.190 --> 09:06.630 So this will basically be Chris. 09:06.630 --> 09:10.380 So this is what this is nothing but str the string. 09:10.380 --> 09:12.960 And finally if I go ahead and define is underscore student. 09:12.960 --> 09:15.180 This is basically my boolean variable right. 09:15.180 --> 09:18.120 So boolean or sorry I will assign it as true. 09:18.120 --> 09:20.490 So this basically becomes my boolean variable. 09:20.520 --> 09:26.520 Now if I go ahead and print the type of any of this right like age. 09:26.520 --> 09:28.110 So I'm going to basically get integer. 09:28.110 --> 09:29.010 The class will be integer. 09:29.040 --> 09:29.700 During the runtime. 09:29.700 --> 09:30.930 It is able to understand it. 09:30.930 --> 09:35.760 If I go ahead and print what is the type of name I'm actually going to get string right. 09:35.790 --> 09:40.980 So similarly you will be able to find out different different types like what classes it basically belongs 09:40.980 --> 09:41.340 to. 09:41.370 --> 09:41.880 Okay. 09:42.240 --> 09:44.790 Now one more thing. 09:44.820 --> 09:50.190 Right here I will discuss about one very important point and understand one thing guys. 09:50.190 --> 09:51.840 Here I'll be showing some example. 09:51.870 --> 09:58.580 But when I go ahead with more session or more different lessons as we go ahead, right, I will be reusing 09:58.580 --> 09:59.270 all these things. 09:59.270 --> 10:04.280 Don't think that I'm just going to write for a single time over here, because this is all things will 10:04.280 --> 10:05.270 again get repeated. 10:05.300 --> 10:07.610 Okay, with all the different, different examples. 10:07.640 --> 10:11.990 Now let me just go ahead and make you understand about type checking and conversion. 10:12.020 --> 10:12.530 Okay. 10:12.680 --> 10:14.390 Now type checking and conversion. 10:14.390 --> 10:15.530 What does this basically mean. 10:15.560 --> 10:16.430 Obviously type checking. 10:16.430 --> 10:17.210 You have known right. 10:17.210 --> 10:19.820 So if I go ahead and write type of height. 10:19.850 --> 10:24.200 So that basically means I'm going to get the uh data type of this height variable. 10:24.230 --> 10:24.440 Right. 10:24.470 --> 10:28.040 So in short I'm actually getting float over here right now. 10:28.070 --> 10:29.390 My question rises. 10:29.390 --> 10:32.540 Can we convert one data type to the other data type. 10:32.630 --> 10:33.350 Is it possible. 10:33.350 --> 10:34.730 So let me just go and show you. 10:34.760 --> 10:38.120 Let's say if I go ahead and write age is equal to 25 right now. 10:38.120 --> 10:44.090 You know that if I go ahead and write print type of age, so what I'm actually going to get it is an 10:44.090 --> 10:45.350 integer, right? 10:45.350 --> 10:48.680 But now I am going to perform some type conversion. 10:48.680 --> 10:53.000 Type conversion basically means I am going to convert this integer value into a string value. 10:53.030 --> 10:53.660 Let's say. 10:53.690 --> 10:59.030 So if I go ahead and write age, underscore str, and if I go and use this str function. 10:59.060 --> 10:59.570 Right. 10:59.720 --> 11:00.500 STR function is. 11:00.500 --> 11:00.710 What? 11:00.740 --> 11:01.100 String. 11:01.100 --> 11:01.370 Right. 11:01.400 --> 11:03.860 This is what is the class that I'm actually getting. 11:03.890 --> 11:07.460 Now if I want to convert this age into string I can use this str. 11:07.460 --> 11:09.320 And I can use this age variable over here. 11:09.350 --> 11:09.770 Right. 11:09.800 --> 11:12.740 Now if I go ahead and write print age. 11:13.100 --> 11:14.450 Print age. 11:14.480 --> 11:16.550 Underscore str okay. 11:16.580 --> 11:22.970 And after that I will just go ahead and write print type of age underscore str right. 11:23.000 --> 11:24.410 So if I go ahead and execute it. 11:24.440 --> 11:30.950 See initially it was int later on when I printed this age underscore str here you can probably see that 11:30.950 --> 11:32.090 I'm getting 25. 11:32.120 --> 11:32.660 Okay. 11:32.780 --> 11:35.540 But the type of this particular value is string. 11:35.570 --> 11:37.340 Right here you can see string. 11:37.340 --> 11:41.690 So this this value from integer it has got converted into strings okay. 11:41.840 --> 11:44.030 Now the question rises Chris. 11:44.030 --> 11:47.060 Uh what are the different types of type conversion can I do. 11:47.090 --> 11:47.630 Okay. 11:47.780 --> 11:49.610 Can can I do something like this. 11:49.610 --> 11:50.390 Can I write. 11:50.420 --> 11:52.760 Age is equal to in string like 25. 11:52.790 --> 11:55.010 And can I convert this into int. 11:55.130 --> 11:56.210 Let's see. 11:56.540 --> 11:56.840 Right. 11:56.870 --> 11:57.950 Let's see this. 11:57.980 --> 11:59.240 So the answer is yes. 11:59.240 --> 12:00.440 You are able to convert it. 12:00.470 --> 12:00.980 Right. 12:00.980 --> 12:05.720 So if I go ahead and print, uh, the type of int of age. 12:05.750 --> 12:06.590 Yes, definitely. 12:06.590 --> 12:07.820 You are able to convert it. 12:07.850 --> 12:08.390 Right. 12:08.390 --> 12:10.160 And here I'm just going to close it. 12:10.160 --> 12:10.430 Yes. 12:10.430 --> 12:11.510 The class is int. 12:11.570 --> 12:12.740 This is fine. 12:12.890 --> 12:16.790 But still I will just go ahead and use one more. 12:16.790 --> 12:17.630 Some more examples. 12:17.630 --> 12:26.450 Let's say if I go ahead and write my name is Krish right now do I, can I convert this into an integer? 12:26.480 --> 12:28.220 The answer is no, right? 12:28.220 --> 12:31.820 Because obviously Krish is a complete sentence, right? 12:31.820 --> 12:36.590 If I talk about 25 in string manner, this is basically a numerical value itself, right? 12:36.620 --> 12:40.400 So even though it is in a string, I can convert this into an int type. 12:40.400 --> 12:43.190 But over here this is my string complete string. 12:43.190 --> 12:45.950 I cannot just convert this into an integer type or a float type. 12:45.950 --> 12:50.630 So here you basically get an error saying that invalid literal for int with base ten Krish. 12:50.660 --> 12:51.170 Right? 12:51.170 --> 12:54.530 So this is the value that you are able to get it over here, right. 12:54.650 --> 12:56.330 Another example some more example. 12:56.330 --> 12:57.980 Let's define some float value. 12:58.010 --> 12:58.430 Right. 12:58.430 --> 13:04.430 So let's say my uh my height is nothing but 6.1 okay. 13:04.640 --> 13:09.530 Or let's say 6.0 or 6.0 or 5.11 okay. 13:09.560 --> 13:10.250 Something. 13:10.280 --> 13:10.850 Okay. 13:11.030 --> 13:19.580 Now if I go ahead and see the type of height, what exactly it is, it is nothing but float, right? 13:19.580 --> 13:22.910 Can I convert this float into an integer? 13:23.210 --> 13:24.140 The answer is yes. 13:24.140 --> 13:29.270 So if I go ahead and write int and I do the type casting for this particular height variable, you'll 13:29.300 --> 13:31.670 be able to see that I'm able to get five right. 13:31.670 --> 13:34.370 That basically means it is just going to remove the decimal, right? 13:34.400 --> 13:35.870 Can I do the opposite again? 13:35.870 --> 13:39.230 Can I again typecast this from int to float again? 13:39.260 --> 13:43.280 Yes I can, and it is going to give me 5.0 right. 13:43.280 --> 13:44.600 So 5.11. 13:44.660 --> 13:47.450 Initially I converted this into an integer I got 5.0. 13:47.480 --> 13:49.340 Then again sorry I got five. 13:49.340 --> 13:51.440 And then again I converted that into float. 13:51.440 --> 13:52.520 So I got 5.0. 13:52.550 --> 13:57.970 So this is some example with respect to the conversion right type checking conversion. 13:57.970 --> 14:00.970 So this is what I really want to show you over here. 14:01.000 --> 14:01.570 Okay. 14:01.690 --> 14:04.030 Now let me do one thing. 14:04.690 --> 14:10.090 Let me talk about one very important concept which is called as dynamic typing okay. 14:10.120 --> 14:12.970 And this is probably the most amazing feature in Python. 14:13.000 --> 14:13.540 Okay. 14:13.570 --> 14:15.880 Let's say I'm going to define a variable ten. 14:15.910 --> 14:19.660 Okay I'm going to define a variable ten okay. 14:19.690 --> 14:23.740 Now let me just go ahead and write print var. 14:25.750 --> 14:31.330 Where I'm going to print this var and I'm going to also print type of var okay. 14:31.750 --> 14:32.830 Type of var. 14:33.280 --> 14:33.790 Perfect. 14:33.790 --> 14:35.530 So this initially is an integer. 14:35.530 --> 14:37.570 Then obviously it should give ten. 14:37.600 --> 14:38.560 It should display ten. 14:38.560 --> 14:40.630 And it should say that hey it is an integer. 14:40.780 --> 14:48.580 Now Python allows the type of a variable to change as the program executes, right? 14:48.610 --> 14:50.500 So let me write down this particular comment. 14:50.560 --> 14:58.300 Python allows the type of variable to change. 14:59.440 --> 15:04.150 To change as the program executes. 15:04.210 --> 15:04.600 Right? 15:04.630 --> 15:05.800 Amazing, right? 15:06.100 --> 15:07.510 Now, what does this basically mean? 15:07.510 --> 15:11.110 Now I can go ahead and change the value of var and I can write. 15:11.140 --> 15:11.740 Hello. 15:11.770 --> 15:12.280 Okay. 15:12.310 --> 15:17.260 And let's say I'm going to print var comma type of var okay. 15:17.290 --> 15:20.260 This time obviously you know what it will output will be string. 15:21.220 --> 15:23.590 If you are not satisfied with this again you can change. 15:23.590 --> 15:27.760 So as you keep on executing the code you can keep on changing it. 15:27.760 --> 15:30.430 Let's say now this time I defined it as a float variable. 15:30.460 --> 15:36.310 Now if I go ahead and write print var okay var comma type of var. 15:36.340 --> 15:41.200 So if I go ahead and execute this here, you'll be able to see that I'm able to get this right. 15:41.200 --> 15:45.250 So see initially it was ten class int hello class str. 15:45.250 --> 15:47.950 And finally 3.14 class is float. 15:47.950 --> 15:49.180 So what is basically happening. 15:49.180 --> 15:54.100 Python is allowing this type of a variable to change as the program gets executed. 15:54.100 --> 15:54.520 Right. 15:54.520 --> 15:56.080 So we can basically do this. 15:56.110 --> 16:00.460 Okay, now, uh, let's do one amazing thing. 16:00.490 --> 16:06.430 Let's just create a simple, uh, application with whatever things we are specifically not. 16:06.460 --> 16:07.000 Okay. 16:07.210 --> 16:09.760 And before that, let me just talk about input. 16:09.790 --> 16:10.000 Okay. 16:10.030 --> 16:11.200 Now, what exactly is input? 16:11.200 --> 16:15.490 Let's say that, uh, a user wants to give some values, right? 16:15.520 --> 16:16.900 Let's say age. 16:16.900 --> 16:18.010 And I have told that. 16:18.010 --> 16:19.990 Hey, user, you give the value. 16:20.020 --> 16:21.220 What is the age? 16:21.250 --> 16:21.790 Okay. 16:22.000 --> 16:23.140 What is the age? 16:23.140 --> 16:24.790 So I, I am a user. 16:24.790 --> 16:26.650 I want to probably give the value over here. 16:26.680 --> 16:34.420 So if I use this right input function and if I print age over here see what will happen. 16:34.420 --> 16:37.240 So once I execute this statement now see what will happen. 16:37.240 --> 16:40.870 So here you can see a input box has got opened. 16:40.870 --> 16:43.750 So here I'm just going to give my uh age. 16:43.750 --> 16:45.880 Let's say the age is 23 okay. 16:45.910 --> 16:47.260 And I'm going to press enter. 16:47.260 --> 16:49.510 So here you can see I'm printing the age now. 16:49.510 --> 16:51.730 One very important thing to show you, right. 16:51.760 --> 16:54.550 What will be the type of this age okay. 16:54.610 --> 16:59.410 So that basically means whenever I'm giving any input from this particular input box by using this input 16:59.410 --> 17:02.050 function, what will be the type of it by default? 17:02.080 --> 17:02.380 Type. 17:02.380 --> 17:04.510 So here I'm going to go ahead and write 23. 17:04.570 --> 17:06.460 And here you can see it is a string type. 17:06.460 --> 17:09.310 So let's say I want to probably get this particular input. 17:09.310 --> 17:12.670 And then also convert this into an integer or float. 17:12.670 --> 17:15.370 So I can again type cast this entire thing. 17:15.400 --> 17:15.880 Right. 17:15.880 --> 17:21.100 So now if I go ahead and execute this and let me just go ahead and write 23 and press enter. 17:21.100 --> 17:23.440 So here you can see I'm getting a class int right. 17:23.440 --> 17:30.670 So this is one very important functionality for uh the entire input function over here. 17:30.670 --> 17:32.740 And this can be very handy. 17:32.740 --> 17:35.230 And it can be used in various places okay. 17:35.260 --> 17:39.700 So I hope you are able to execute this and you are able to understand this. 17:39.700 --> 17:41.890 So I'm just going to show you one example again. 17:41.920 --> 17:43.210 Now let us do one thing. 17:43.210 --> 17:47.410 Let us simply create one simple calculator okay. 17:47.500 --> 17:50.050 Now this simple calculator will be amazing. 17:50.050 --> 17:55.020 So here you can just see that what this calculator is doing I'm giving two numbers. 17:55.020 --> 17:58.800 Uh, again, I'm using this input, uh, number one again. 17:58.800 --> 18:00.660 Number two, then some. 18:00.660 --> 18:04.470 I'm doing num plus num one plus num two difference num one minus two. 18:04.500 --> 18:08.490 And product is num one multiplied by num two num one divided by num two. 18:08.520 --> 18:11.340 We will discuss more about this operators as we go ahead. 18:11.370 --> 18:14.010 And we are just going to display all the sum difference and all. 18:14.010 --> 18:15.720 So let's go ahead and execute it. 18:15.720 --> 18:17.730 Let's say the first number is 56. 18:17.730 --> 18:20.820 I'll go ahead and press enter again I've got my another cell. 18:20.850 --> 18:26.790 Let's say I'm going to write 43 or 10 something and press enter. 18:26.790 --> 18:31.800 So here you can see I'm able to see all the ounces like some difference product and quotient. 18:31.830 --> 18:32.400 Right. 18:32.490 --> 18:33.600 So yes. 18:33.600 --> 18:35.850 Uh, this was uh, amazing. 18:35.850 --> 18:40.530 This was I guess, you, you are able to understand many things about variables. 18:40.830 --> 18:42.540 Uh, this was it from my side. 18:42.540 --> 18:46.470 Uh, in the next video, I am going to probably discuss more about data types. 18:46.470 --> 18:49.350 And then finally we'll also be discussing about operators. 18:49.350 --> 18:50.670 What are the different different data types. 18:50.670 --> 18:52.050 Also we need to discuss about. 18:52.050 --> 18:53.550 So yes, this was it from my side. 18:53.550 --> 18:54.660 I will see you in the next video. 18:54.660 --> 18:54.990 Thank you.