WEBVTT 00:00.200 --> 00:00.920 Hello guys. 00:00.920 --> 00:03.530 So we are going to continue the discussion with respect to Python. 00:03.530 --> 00:06.470 And now we are going to see some of the examples already. 00:06.470 --> 00:11.780 In our previous video we saw many topics regarding functions, and there are a lot of advanced topics 00:11.780 --> 00:12.650 that are going to come. 00:12.650 --> 00:17.630 But before that I thought, why not create some examples and show you how we can probably solve those? 00:17.660 --> 00:18.140 Right? 00:18.140 --> 00:22.730 So first example over here is that we need to create a function for temperature conversion. 00:22.760 --> 00:27.050 So temperature conversion basically means we need to convert Celsius to Fahrenheit or Fahrenheit to 00:27.080 --> 00:27.830 Celsius. 00:27.830 --> 00:29.450 So how do we define a function. 00:29.450 --> 00:30.350 We'll go ahead and see. 00:30.350 --> 00:32.150 So let's go ahead and see this example. 00:32.150 --> 00:34.610 So first of all I will go ahead and create my function. 00:34.610 --> 00:38.000 Let's say I will write convert underscore temperature. 00:38.000 --> 00:40.130 So this is my function over here. 00:40.250 --> 00:42.290 And here I will give two parameters. 00:42.290 --> 00:46.190 One is temperature and one is the unit that I really want to convert it. 00:46.220 --> 00:52.610 Let's say if I give the unit over here as C, that basically means I need to convert this, uh, this 00:52.640 --> 00:55.670 entire temperature from Celsius to Fahrenheit. 00:55.700 --> 00:56.210 Right. 00:56.210 --> 00:59.090 And if I give the unit as F, right. 00:59.090 --> 01:02.460 So I need to convert the temperature from Fahrenheit to Celsius. 01:03.120 --> 01:03.480 Right. 01:03.480 --> 01:06.240 So let me just go ahead and give a docstring. 01:06.240 --> 01:20.880 So this function converts temperature between Celsius and Fahrenheit. 01:20.910 --> 01:21.510 Okay. 01:21.630 --> 01:27.570 So uh this is what is my definition of this particular function over here. 01:27.570 --> 01:30.330 And uh, we will go ahead and write our code. 01:30.360 --> 01:30.630 Right. 01:30.630 --> 01:36.090 So here let's say I will go ahead and write if unit is double equal to capital C right. 01:36.090 --> 01:41.100 If I'm giving this particular unit that basically means I need to convert my temperature from Celsius 01:41.100 --> 01:41.610 to Fahrenheit. 01:41.640 --> 01:45.870 So I'm going to return, uh, temperature multiplied by. 01:45.870 --> 01:47.820 And I'll do the operation nine by five. 01:47.850 --> 01:48.180 Okay. 01:48.210 --> 01:51.660 And here let me just give the bracket nine by five. 01:51.930 --> 01:52.680 Uh oh. 01:52.680 --> 01:52.950 Sorry. 01:52.950 --> 01:54.420 I need to first of all, multiply it. 01:54.420 --> 01:57.120 Then I will go ahead and do the addition plus 32. 01:57.150 --> 02:02.800 So this is the formula of converting a Celsius to Fahrenheit with respect to the temperature. 02:02.830 --> 02:03.160 Okay. 02:03.190 --> 02:05.830 So this is the simple formula that we specifically use. 02:05.830 --> 02:12.970 And this in turn will be converting Celsius to Fahrenheit. 02:13.240 --> 02:13.480 Okay. 02:13.510 --> 02:14.290 Fahrenheit. 02:14.590 --> 02:16.000 Fahrenheit. 02:16.030 --> 02:16.450 Okay. 02:16.870 --> 02:20.110 Then, uh, let me go ahead and write, Elif. 02:20.140 --> 02:20.530 Okay. 02:20.560 --> 02:23.410 So here we are going to use everything, whatever things you have learned. 02:23.410 --> 02:27.280 Let's say there are some examples that I'm going to use dictionaries, some examples where I'm going 02:27.310 --> 02:29.110 to use, uh, list and all. 02:29.230 --> 02:32.800 In this particular case, you can probably see that I'm also using if Elif. 02:32.800 --> 02:33.160 Right. 02:33.160 --> 02:38.050 So if Elif, the unit is double equal to Fahrenheit. 02:38.080 --> 02:40.720 Okay, then I'm going to basically return. 02:40.750 --> 02:41.200 Okay. 02:41.230 --> 02:48.400 And with for this particular temperature, I need to minus first of all, 32 and then multiply it by 02:48.400 --> 02:49.750 five by nine. 02:50.230 --> 02:50.770 Okay. 02:50.770 --> 02:55.450 And this will basically give us uh, our Fahrenheit to Celsius. 02:55.450 --> 02:55.810 Right. 02:55.810 --> 02:56.980 So this is the formula. 02:56.980 --> 02:59.710 If you go ahead and do the Google search. 02:59.710 --> 03:02.400 Also how to convert Celsius to Fahrenheit. 03:02.430 --> 03:04.350 So this is the formula that you usually get. 03:04.380 --> 03:04.890 Okay. 03:04.980 --> 03:07.200 So uh that's it. 03:07.200 --> 03:08.880 This is what it is, right? 03:08.880 --> 03:14.130 And if I don't give any information for our third parameter we need to also handle that. 03:14.130 --> 03:15.870 That is if I'm not giving any unit. 03:15.870 --> 03:17.790 So I will just go ahead and return. 03:17.790 --> 03:18.900 None okay. 03:18.930 --> 03:19.770 None. 03:20.130 --> 03:20.970 So done. 03:20.970 --> 03:23.310 So here I'm going to basically use this function. 03:23.310 --> 03:26.460 Now let me go ahead and call this function as convert temperature. 03:26.460 --> 03:32.220 And if I go ahead and write like a value let's say temperature I'm going to give 25. 03:32.250 --> 03:32.520 Right. 03:32.520 --> 03:34.470 And this is in Celsius. 03:34.470 --> 03:35.100 Right. 03:35.550 --> 03:38.310 Uh then I'm going to go ahead and print it. 03:38.460 --> 03:38.940 Right. 03:38.940 --> 03:41.040 And I will be basically getting converted. 03:41.040 --> 03:45.060 We are converting this from 29 degree Celsius to Fahrenheit. 03:45.090 --> 03:48.000 The next one that I'm actually going to do is print. 03:48.030 --> 03:48.570 Okay. 03:48.600 --> 03:52.050 Again I will go ahead and call my convert temperature. 03:52.050 --> 03:56.340 And here I'm actually going to give 77 comma F. 03:56.340 --> 03:57.000 Right. 03:57.000 --> 03:58.920 And this I will be able to get the answer. 03:58.920 --> 04:00.060 Let's see whether it works. 04:00.060 --> 04:07.180 Yes 25 is nothing but 77 degree Fahrenheit, and 77 degree Fahrenheit is nothing but 25 degree Celsius. 04:07.180 --> 04:09.010 So this is how the conversion is done. 04:09.010 --> 04:11.110 And I feel that formula is absolutely right. 04:11.110 --> 04:12.190 What you have written. 04:12.520 --> 04:16.180 Um, and here you can just see based on units we are able to do it. 04:16.180 --> 04:18.520 So this is our first example. 04:18.760 --> 04:23.800 Um, now what I'm actually going to do is that I'm going to show you one more amazing example, which 04:23.800 --> 04:26.440 is called as Password strength checker. 04:26.470 --> 04:26.890 Okay. 04:26.920 --> 04:28.510 Now what exactly is this? 04:28.510 --> 04:31.930 Uh, let's say that we are creating our user ID or login. 04:31.930 --> 04:34.180 And over there we specifically give passwords. 04:34.180 --> 04:34.570 Right. 04:34.570 --> 04:35.230 And it is. 04:35.350 --> 04:38.230 And most of the people just write password as 12345. 04:38.260 --> 04:41.380 So we need to have a strong password check okay. 04:41.800 --> 04:46.810 So I'll be giving some of the check over here to just uh, making you understand whether it is a weak 04:46.810 --> 04:49.900 password or a true power or a very strong password. 04:49.930 --> 04:50.350 Right. 04:50.350 --> 04:55.120 So first of all, I will go ahead and write my definition is strong password. 04:55.930 --> 05:01.490 So this function will be responsible in checking whether a password is strong or not okay. 05:02.000 --> 05:05.780 So here you can see I will just go ahead and write my docstring. 05:05.810 --> 05:13.670 This function checks if the password is strong or not. 05:14.420 --> 05:15.110 Okay. 05:16.490 --> 05:17.660 Now let me go ahead and write. 05:17.690 --> 05:22.310 Let's say first condition that first criteria I want to put with respect to the password. 05:22.310 --> 05:25.550 My password should be minimum of eight character right. 05:25.550 --> 05:34.910 So I will go ahead and write if length of if length of password is less than eight is less than eight. 05:34.910 --> 05:39.710 So that basically means I'm going to just say, hey, this is a very bad password in short. 05:39.710 --> 05:44.870 So I will just go ahead and say false, because this function that I'm actually creating is basically 05:44.870 --> 05:46.850 checking whether a password is strong or not. 05:46.850 --> 05:48.590 So right now the password is not strong. 05:48.590 --> 05:49.880 So I'm returning false. 05:49.910 --> 05:52.580 Then let me just go ahead and write another condition. 05:52.580 --> 05:53.810 If not okay. 05:53.810 --> 05:57.350 So if not is one condition, if not any okay. 05:57.620 --> 06:02.850 So here we are just going to see whether this Character is having any digit or not. 06:02.880 --> 06:07.290 Write whatever character, whatever password we are specifically giving, whether it is having any digit 06:07.290 --> 06:07.860 or not. 06:07.890 --> 06:08.400 Right. 06:08.400 --> 06:14.940 So what I'm actually going to do, if not, is basically like comparing whether there is not present 06:14.940 --> 06:15.240 or not. 06:15.240 --> 06:15.450 Right. 06:15.480 --> 06:16.170 Something like that. 06:16.170 --> 06:20.490 So I will go ahead and use a for loop for character in password. 06:20.490 --> 06:23.100 So we will go ahead and see each and every character. 06:23.100 --> 06:28.230 And here I will just go ahead and see whether this character is having any digit or not. 06:28.350 --> 06:28.830 Okay. 06:28.860 --> 06:34.260 So each digit is a function that is present in every characters or string, right. 06:34.260 --> 06:39.030 So I'm just going to compare for every character in this specific password, whether it is having a 06:39.030 --> 06:39.840 digit or not. 06:39.870 --> 06:40.440 Right. 06:40.470 --> 06:42.990 If there is not any digits right. 06:43.020 --> 06:45.960 So what I will do I will again return false. 06:45.990 --> 06:46.530 Okay. 06:46.650 --> 06:50.040 Please see carefully what kind of condition I'm using. 06:50.070 --> 06:50.550 Right. 06:50.550 --> 06:55.320 So this is just like any function or an inbuilt function that is present in Python. 06:55.320 --> 06:58.950 And we are iterating through each and every characters in that password. 06:58.950 --> 07:00.660 And we are seeing whether it is a digit or not. 07:00.690 --> 07:01.140 Right. 07:01.150 --> 07:05.020 And this is dessert is a kind of function that is available in strings. 07:05.050 --> 07:05.260 Okay. 07:05.290 --> 07:07.600 So this is one of the check that I really want to do. 07:07.810 --> 07:08.380 Right. 07:08.830 --> 07:12.670 Then I will also be checking with respect to the password is lower. 07:12.670 --> 07:19.240 If all the characters is lower then also we should return it false saying that hey it is not exactly 07:19.240 --> 07:20.230 a good password, right? 07:20.230 --> 07:21.670 So I will go ahead and write. 07:21.700 --> 07:22.870 If not any. 07:22.900 --> 07:25.150 Again, I will go ahead and write my next condition. 07:25.150 --> 07:32.380 And here this time I will say hey for car in password and here I'm going to check. 07:32.410 --> 07:32.920 Right? 07:32.920 --> 07:34.960 I'm what I have to check over here. 07:34.990 --> 07:37.540 Whether my character is lower. 07:37.540 --> 07:40.990 So low is lower is one of the function that is again present in Python. 07:40.990 --> 07:43.720 Sorry for character in password I have to write. 07:43.750 --> 07:44.290 Okay. 07:44.620 --> 07:49.240 Uh, I'm just checking whether the character is lower or not for all the characters that are present 07:49.240 --> 07:49.810 over there. 07:49.810 --> 07:53.140 And if it is present, I'm just going to return the false. 07:53.230 --> 07:53.890 Okay. 07:54.010 --> 07:56.800 So guys, now we have written the condition still here. 07:56.800 --> 08:00.340 We have also checked like all the characters should not be lowercase. 08:00.370 --> 08:00.880 Okay. 08:00.950 --> 08:08.000 Now, similarly, all the characters should also not be, you know, uppercase, you know, and we'll 08:08.000 --> 08:09.140 also check for that. 08:09.140 --> 08:09.440 Right. 08:09.440 --> 08:14.420 So here I'm going to write if if not in if not any. 08:14.420 --> 08:17.510 And this time I will be using Cat. 08:17.540 --> 08:19.940 Dot is upper right. 08:19.940 --> 08:25.700 So there are a lot of functions with respect to strings which I can specifically use over here. 08:25.700 --> 08:30.920 And let me just go ahead and write for cat in password okay. 08:30.980 --> 08:37.100 And this we will go ahead and check it out and we'll again write a return false okay. 08:37.250 --> 08:38.840 Now this is there. 08:38.870 --> 08:40.520 Now let's think of more things. 08:40.550 --> 08:44.090 You know uh let's see for any special characters. 08:44.090 --> 08:51.170 So for special character, uh, I would like to add many special characters that are probably present, 08:51.200 --> 08:51.680 right. 08:51.710 --> 08:57.290 If not any, let's say in our character, if there is no special character like this, then also I can 08:57.290 --> 09:01.840 say that, hey, this is basically a weak password right? 09:01.840 --> 09:03.790 At least it should have one upper. 09:03.970 --> 09:04.630 You know. 09:04.660 --> 09:08.290 At least it should have one digits, you know, so this kind of condition. 09:08.290 --> 09:11.740 So here I've used all special characters over here for character in password. 09:11.740 --> 09:15.880 And then if it is not present we are just going to return false. 09:15.910 --> 09:21.070 If everything satisfies then we will go ahead and return true okay. 09:21.190 --> 09:23.200 So here all return false are there. 09:23.200 --> 09:25.150 And then here return true is there. 09:25.150 --> 09:25.420 Right. 09:25.420 --> 09:30.460 So if all this condition are false then uh, if all this condition does not get satisfied, then we 09:30.490 --> 09:31.510 are just going to return true. 09:31.510 --> 09:36.040 Saying that hey, this is super amazing password and it is a strong password. 09:36.040 --> 09:38.350 Now let me just go ahead and call the function. 09:38.350 --> 09:41.560 So calling the function over here okay. 09:41.680 --> 09:45.070 And let me just give some of the things over here. 09:45.100 --> 09:45.310 Right. 09:45.310 --> 09:46.840 So I'll go ahead and write. 09:47.530 --> 09:51.310 Print is underscore strong password. 09:51.310 --> 09:53.020 And let me just give one example. 09:53.050 --> 09:55.210 Let's say I have a capital letter. 09:55.210 --> 09:58.420 And I will write a small letter again a capital letter. 09:58.420 --> 10:00.670 And this is my password okay. 10:00.670 --> 10:05.960 But here you can see that I'm not having any special character or other than that, I think everything 10:05.960 --> 10:11.390 is getting satisfied and digit is also not there, so I should definitely be getting false for this. 10:11.420 --> 10:16.040 One more way is that I can go ahead and print okay is strong password. 10:16.040 --> 10:20.210 And let me just go ahead and use some special characters. 10:20.210 --> 10:26.810 So I will go ahead and write str and let me just go ahead and use a zero over here. 10:26.840 --> 10:27.380 Okay. 10:27.410 --> 10:31.160 And I will be using ng capital P w d. 10:31.280 --> 10:33.830 And let me use one special character like exclamation. 10:33.860 --> 10:34.340 Okay. 10:34.370 --> 10:36.680 Now let's see whether both of them. 10:36.680 --> 10:40.910 I think this should basically be giving me false and this should be giving me true. 10:40.940 --> 10:45.980 Okay, so now if I execute this here, you can see since I do not have a digit or a special character, 10:45.980 --> 10:48.020 I'm actually getting false here. 10:48.020 --> 10:52.790 I have both, uh, a digit and a special character. 10:52.790 --> 10:56.150 So and that is the reason I am also having a capital letter over here. 10:56.150 --> 10:57.770 So that is the reason I am getting true. 10:57.770 --> 11:02.230 So this is one amazing example with respect to password strength checker. 11:02.230 --> 11:07.960 Just with the help of one function, we are able to do this kind of, uh, validation, and we are able 11:07.960 --> 11:08.980 to execute it. 11:09.010 --> 11:09.520 Okay. 11:09.550 --> 11:13.210 Now, uh, let's go with the third example. 11:13.240 --> 11:19.210 Now, this specific example I have actually selected, uh, just to make sure to show you like, uh, 11:19.210 --> 11:22.000 how in the real world application this can be used. 11:22.000 --> 11:26.200 So calculate the total cost of items in a shopping cart. 11:26.200 --> 11:28.330 So here we are going to define a function. 11:28.330 --> 11:34.990 So I will go ahead and write def calculate underscore total underscore cost. 11:35.140 --> 11:37.330 And here I'm going to give my cart. 11:37.360 --> 11:38.020 Okay. 11:38.050 --> 11:43.120 Now this cart will basically be having a lot of uh you know items over there. 11:43.120 --> 11:46.210 And we can also give in the form of dictionary. 11:46.210 --> 11:51.640 So right now I'm just going to do pass because first of all, I will see what kind of data I have. 11:51.670 --> 11:52.180 Okay. 11:52.180 --> 11:56.710 So let me just go ahead and show you some of the example with respect to cart data. 11:56.770 --> 11:59.170 And since we have already learned about dictionary. 11:59.170 --> 12:05.350 So we will go ahead and write cart is equal to and will create a list and this will be a list of dictionaries. 12:05.380 --> 12:13.480 Okay, so let's say my first item is something like with key value pairs like name is equal to uh let's 12:13.480 --> 12:14.860 say I have Apple. 12:15.160 --> 12:15.670 Okay. 12:15.700 --> 12:21.730 Then I have price which is equal to 0.5. 12:22.150 --> 12:26.050 Then I have specifically quantity okay. 12:26.320 --> 12:29.770 And this quantity will be equal to four okay. 12:30.130 --> 12:34.330 Uh now I will go ahead and create my next, uh example. 12:34.330 --> 12:37.780 And let's say this point $5. 12:37.780 --> 12:39.220 I have written like that right. 12:39.310 --> 12:40.240 Obviously. 12:40.300 --> 12:43.630 So here let me just go ahead and and name should be banana. 12:43.660 --> 12:44.290 Okay. 12:44.320 --> 12:46.210 Price will be $0.3. 12:46.240 --> 12:50.560 Let's say quantity I'll say six six bananas. 12:50.590 --> 12:51.880 This is the price. 12:51.880 --> 12:56.230 And let me just go ahead and again add one more item over here. 12:56.260 --> 12:56.830 Right. 12:58.300 --> 13:01.880 Now let me just go ahead and write one more like orange. 13:01.910 --> 13:02.510 Okay. 13:02.540 --> 13:06.200 The price will be 0.7 and quantity. 13:06.200 --> 13:07.610 I can write as three. 13:07.640 --> 13:08.090 Okay. 13:08.120 --> 13:10.040 So this is my cart. 13:10.070 --> 13:10.460 Okay. 13:10.490 --> 13:16.160 With respect to all the items that I have, then I will just go ahead and write my function over here. 13:16.160 --> 13:18.770 So let me just go ahead and create a temporary variable. 13:18.800 --> 13:20.360 Total cost is equal to zero. 13:20.420 --> 13:22.880 Now all I have to do is that I have to explore. 13:22.910 --> 13:25.550 I have to probably go through this each and every cart. 13:25.970 --> 13:28.100 Uh, take the price. 13:28.130 --> 13:28.760 Okay. 13:28.790 --> 13:32.870 And see, this price is basically for one quantity. 13:32.900 --> 13:33.170 Okay. 13:33.200 --> 13:36.560 So we will go ahead and multiply with this many number of quantities. 13:36.590 --> 13:37.070 Okay. 13:37.100 --> 13:40.160 And again we have to retrieve the data from this particular dictionary. 13:40.160 --> 13:42.200 And then we will be doing the total sum. 13:42.230 --> 13:42.680 Okay. 13:42.680 --> 13:46.760 So now let me just go ahead and write and write from item in cart. 13:46.760 --> 13:48.530 So I will go ahead and explore this. 13:48.560 --> 13:49.010 Okay. 13:49.100 --> 13:50.750 So I will just go ahead and write. 13:50.780 --> 13:54.830 Total cost is equal to or plus equal to. 13:54.860 --> 13:55.190 Okay. 13:55.220 --> 13:58.460 So just like an increment operation where we are adding something. 13:58.490 --> 14:01.750 Then here I'm going to write item of Price. 14:01.780 --> 14:02.470 Okay. 14:02.500 --> 14:03.820 Item of price. 14:03.820 --> 14:11.200 So this for every item of price we are just going to multiply with the item of quantity. 14:11.230 --> 14:11.770 Okay. 14:11.770 --> 14:14.170 So let me just go ahead and write it down. 14:14.290 --> 14:16.510 Then I'll be getting my total cost. 14:16.870 --> 14:19.810 Then I can go ahead and return the total cost. 14:19.810 --> 14:25.540 So this function is just going to multiply the price with respect to all the quantity for each and every 14:25.540 --> 14:26.050 item. 14:26.050 --> 14:28.960 Now quickly let me just go ahead and call the function. 14:28.960 --> 14:33.160 So here I'm going to write calling the function okay. 14:33.190 --> 14:39.820 And here I will write total underscore cost is equal to calculate total cost. 14:39.820 --> 14:42.640 And here I'm going to give my data as cart. 14:42.730 --> 14:45.760 Now let's go ahead and execute it I'll press shift enter. 14:46.150 --> 14:48.040 And here uh okay. 14:48.040 --> 14:52.780 Let me just go ahead and print this total cost because we have not displayed anything. 14:52.930 --> 14:55.750 Now here you can see 5.889. 14:55.750 --> 14:59.080 So this is my total cost right. 14:59.080 --> 15:01.850 With respect to all the items that I have actually bought. 15:01.940 --> 15:02.390 Okay. 15:02.420 --> 15:04.010 And this is amazing. 15:04.010 --> 15:07.130 I'm able to see the total cost of my entire cart. 15:07.130 --> 15:10.370 So here we have just created a function which is taking the cart. 15:10.370 --> 15:12.590 Items and cart can be given as a dictionary. 15:12.590 --> 15:14.420 List whatever things you really want. 15:14.450 --> 15:17.960 Then we'll iterate through each and everything and we'll calculate the cost. 15:18.080 --> 15:18.800 Perfect. 15:18.800 --> 15:21.320 Uh, let's go ahead and see one more example. 15:21.320 --> 15:26.570 Uh, this time, what we are basically going to do over here is that we are going to check or we are 15:26.570 --> 15:31.910 going to create a function which will be checking if a string is palindrome. 15:31.910 --> 15:33.830 Now what does palindrome basically mean? 15:33.830 --> 15:37.250 So if you just want to understand about palindrome right. 15:37.280 --> 15:43.460 Some of the examples let's say if I use this string a b a, if you read it from the front direction, 15:43.970 --> 15:44.870 it is ABBA. 15:44.900 --> 15:48.230 If you read it from the backward direction, it is again ABBA only, right? 15:48.230 --> 15:50.900 So from front and back both are same. 15:50.930 --> 15:56.090 Okay, so we are going to basically write a function which will be able to do the check for any string 15:56.090 --> 16:01.340 from whether from the front it is equal and from the back it is equal with respect to the characters 16:01.340 --> 16:02.670 that we have, it should be safe. 16:02.700 --> 16:05.790 Okay, so here let us go ahead and define a function. 16:05.790 --> 16:08.430 So I'm going to write is underscore palindrome. 16:08.430 --> 16:11.370 So I'll just go ahead and write. 16:11.370 --> 16:13.530 My function is underscore palindrome. 16:13.620 --> 16:16.410 And here I'm going to give my string okay. 16:16.680 --> 16:23.070 Now the best way to do is that whatever string I write right between all the spaces. 16:23.070 --> 16:24.690 First of all I should remove it. 16:25.020 --> 16:26.190 So I'll take the string. 16:26.190 --> 16:30.390 I'll write s dot lower because I have to also do the lowering of all the characters. 16:30.390 --> 16:34.020 And let me just replace all the empty string. 16:34.050 --> 16:34.680 Okay. 16:34.710 --> 16:36.930 With a string, right? 16:36.960 --> 16:39.720 With like I should just remove that empty spaces. 16:40.440 --> 16:47.670 Now, the best way to do this is that I hope everybody knows in string we have discussed about, uh, 16:47.730 --> 16:49.800 you know, slicing operations and all. 16:49.800 --> 16:51.810 So I will just go ahead and write colon. 16:51.810 --> 16:53.070 Colon minus one. 16:53.100 --> 16:53.610 Okay. 16:53.640 --> 17:01.470 Now, if this string is, uh, if I see this is what I'm getting the reverse of a string. 17:01.480 --> 17:01.990 right? 17:02.020 --> 17:06.940 If I'm writing this particular code, I just need to compare this with my s, right? 17:06.970 --> 17:11.410 So if I go ahead and write s double equal to, this will either give true or false. 17:11.410 --> 17:15.190 This is basically the reverse of this specific string itself, right? 17:15.220 --> 17:19.540 So if both of them are equal then we can definitely say that it is a palindrome. 17:19.570 --> 17:24.400 Now let us go ahead and see here, uh, I will go ahead and call this palindrome. 17:24.400 --> 17:26.770 Now I in in Google. 17:26.770 --> 17:29.710 Also you can search for different different uh text. 17:29.740 --> 17:30.310 Right. 17:30.310 --> 17:39.730 So I will use a sentence which is called as a man a plan a canal Panama. 17:39.760 --> 17:40.180 Okay. 17:40.210 --> 17:42.310 Now if you read from here. 17:42.340 --> 17:42.820 Right. 17:42.820 --> 17:45.460 And if you read from the reverse, it is almost same. 17:45.490 --> 17:46.660 See a man. 17:46.690 --> 17:46.990 Right. 17:46.990 --> 17:49.120 So if it is starting from a man. 17:49.150 --> 17:54.400 So here also from backwards, if I read a man is over here, right. 17:54.400 --> 17:55.870 Then again a plan. 17:55.900 --> 17:58.480 So A is over here and plan is still here right. 17:58.480 --> 18:01.240 So I if you read this particular sentence it is reverse. 18:01.270 --> 18:03.020 Again it is almost same, right? 18:03.050 --> 18:04.670 So let's go ahead and print this. 18:04.670 --> 18:09.980 And next one I will just go ahead and take one sentence which is not palindrome. 18:09.980 --> 18:11.720 So let me just go ahead and write hello. 18:11.720 --> 18:17.150 So in hello case I don't have the same sentence from forward or backward right. 18:17.180 --> 18:17.900 It is not equal. 18:17.900 --> 18:21.350 So first one should be giving me true and one should be giving me false. 18:21.350 --> 18:22.880 So here you can see it is true. 18:22.880 --> 18:24.920 And the second one is basically false. 18:24.920 --> 18:28.880 So this is one amazing example with respect to palindrome. 18:28.880 --> 18:34.520 And just by using this string operation slicing operation how easily you are able to do it. 18:34.550 --> 18:35.060 Okay. 18:35.090 --> 18:40.760 Now the next example that we are basically going to see is something called as factorial of a number 18:40.760 --> 18:41.570 using recursion. 18:41.570 --> 18:42.710 Now what is recursion? 18:42.740 --> 18:44.540 Recursion is nothing but I. 18:44.570 --> 18:49.520 If I create a function, that function inside, the body of that function will be called again and again. 18:49.550 --> 18:53.900 Okay, and if I talk about factorials, let's say I want to calculate five factorial. 18:53.900 --> 18:59.420 So it is nothing but five into four into three into two into one. 18:59.420 --> 18:59.690 Right. 18:59.690 --> 19:02.670 So this basically is the operation of any factorials. 19:02.700 --> 19:03.060 Right. 19:03.060 --> 19:06.210 So I have to write a function which will be factorial. 19:06.210 --> 19:09.300 And let's say I have given I want a factorial for five. 19:09.330 --> 19:09.930 Right. 19:09.930 --> 19:16.800 So first condition will be that if n is equal to zero right then what I need to do, I just need to 19:16.800 --> 19:17.460 return one. 19:17.490 --> 19:17.700 Right. 19:17.700 --> 19:20.160 Because five into four into three into one right. 19:20.160 --> 19:21.450 So three into two into one. 19:21.450 --> 19:22.470 It should be like that. 19:22.590 --> 19:24.780 If I'm starting from five it should end till one. 19:24.780 --> 19:28.200 So if n becomes zero I need to just return one okay. 19:28.230 --> 19:36.660 Else I will go ahead and just use one simple return n multiplied by factorial n minus one. 19:36.690 --> 19:37.380 Right? 19:37.380 --> 19:41.490 So here I am calling this particular function right. 19:41.490 --> 19:43.290 So initially if I give five right. 19:43.290 --> 19:44.340 So what will happen. 19:44.340 --> 19:45.630 This condition will become false. 19:45.630 --> 19:49.500 So it will just go ahead and write five multiplied by factorial of four. 19:49.530 --> 19:51.300 Then again factorial of four. 19:51.300 --> 19:56.160 When it is called it will be four into factorial of three, then three into factorial of two, then 19:56.160 --> 19:59.430 two into factorial of one, then one into factorial of zero. 19:59.430 --> 20:02.630 When zero comes, return one, so it will be multiplied by one, right? 20:02.660 --> 20:06.920 So now if I just go ahead and call the function, it will be nothing. 20:06.920 --> 20:10.970 But I can just go ahead and write factorial with respect to phi. 20:10.970 --> 20:13.340 And here you can see this is my output. 20:13.340 --> 20:16.340 If I want factorial for six this is the output. 20:16.370 --> 20:18.680 Here you can see that I'm able to get it right. 20:18.710 --> 20:21.410 And this is what is called as recursion and recursion. 20:21.410 --> 20:26.720 Inside a function you're calling the same function unless and until based on this condition it will 20:26.720 --> 20:27.830 keep on executing. 20:27.860 --> 20:28.370 Okay. 20:29.210 --> 20:34.670 Uh, so there are two more examples of function to read a file and count the frequency of the word. 20:34.700 --> 20:39.560 Okay, I know I have not discussed much about file operation yet. 20:39.590 --> 20:40.100 Okay. 20:40.100 --> 20:44.600 But I really want to show you like, let's say that I have one file over here. 20:44.630 --> 20:47.660 Sample text I have written two line of code. 20:47.660 --> 20:48.350 Hello, world. 20:48.350 --> 20:48.800 How are you? 20:48.800 --> 20:49.580 My name is Krish. 20:49.610 --> 20:50.150 Okay. 20:50.480 --> 20:55.370 Uh, as we go ahead, we'll be discussing more about, uh, reading file and doing file operation. 20:55.370 --> 20:59.780 But here I just want to give you an example, like how we can create a function to this. 20:59.810 --> 21:01.130 Do this task okay. 21:01.130 --> 21:02.730 So first of all, what I'll do. 21:02.940 --> 21:05.010 So my task is very simple over here. 21:05.160 --> 21:08.310 I will try to read a file and count the frequency of each word. 21:08.340 --> 21:08.700 Right. 21:08.730 --> 21:10.530 So how many times each word is present? 21:10.560 --> 21:11.070 Okay. 21:11.070 --> 21:19.050 So quickly we will go ahead and write definition count underscore word underscore frequency okay. 21:19.380 --> 21:22.530 And now I'm just going to give my file path. 21:23.160 --> 21:27.570 Uh the best way to read file path is by using with open function. 21:27.570 --> 21:32.640 Open function is there in Python where you can specifically use and open any kind of file. 21:33.330 --> 21:35.520 So I will go ahead and write word underscore count. 21:35.520 --> 21:38.880 And I know that since I need to count the frequency of each word. 21:38.880 --> 21:40.650 So I need a dictionary over here. 21:40.650 --> 21:42.330 So this will be an empty dictionary. 21:42.750 --> 21:47.130 Now I'll go ahead and write with open my file underscore path. 21:47.130 --> 21:49.680 And this will open in my read mode. 21:49.710 --> 21:50.400 Okay. 21:50.940 --> 21:53.430 So for reading mode I will give it in string okay. 21:53.460 --> 21:57.810 And there is also like write mode and all which we will be discussing as we go ahead in the upcoming 21:57.810 --> 21:58.470 sessions. 21:58.470 --> 22:01.170 And then we will go ahead and write as file. 22:01.200 --> 22:04.390 Then we will go ahead and write for line in file. 22:04.420 --> 22:05.050 Okay. 22:05.170 --> 22:11.680 And we are just going to write words is equal to line dot split okay. 22:12.040 --> 22:13.360 Line dot split. 22:13.870 --> 22:17.680 So we are splitting it based on new line characters. 22:17.680 --> 22:22.540 We are going through this particular file right with respect to that. 22:22.570 --> 22:22.990 Okay. 22:23.020 --> 22:28.240 Now once I get the words right, once we by using this particular line of code, we will be getting 22:28.240 --> 22:34.420 words because every space it will try to calculate it will split it and it will retrieve all these words. 22:34.450 --> 22:34.960 Okay. 22:34.990 --> 22:40.960 Now once we get the words, what I will do is that I will go ahead and write for words in word. 22:40.990 --> 22:41.620 Okay. 22:41.650 --> 22:48.700 And here I'm going to basically write word is equal to word dot lower. 22:48.730 --> 22:49.030 Okay. 22:49.060 --> 22:50.890 So I'm going to do the lower operation. 22:50.890 --> 22:55.930 First of all I really need to make small uh for all the words okay. 22:55.960 --> 23:01.630 Then uh, let's say I want to probably do dot strip operation. 23:01.880 --> 23:02.240 Okay. 23:02.270 --> 23:05.930 And if you don't know about dot strip, uh, you'll be able to understand. 23:05.930 --> 23:12.500 Whenever I give any specific words, it should be able to split based on any kind of characters because 23:12.500 --> 23:13.790 I need each and every word. 23:13.790 --> 23:19.100 So I'll be using some special characters like colon slash, exclamation, everything. 23:19.130 --> 23:22.280 I'll be using this even, uh, like it should. 23:22.310 --> 23:24.590 It should also split h e also separately. 23:24.620 --> 23:24.830 Right. 23:24.830 --> 23:26.600 So that is the reason I've given this also. 23:26.600 --> 23:31.970 And if there is exclamation everything, I'll try to strip it and I will try to get the word okay. 23:32.000 --> 23:38.270 Then I will just go ahead and write word of count and I will take that specific word okay. 23:38.300 --> 23:40.190 Please focus on the logic okay. 23:40.220 --> 23:41.810 Logic is super important. 23:41.810 --> 23:44.690 And logic, you become better when you keep on practicing. 23:44.690 --> 23:48.800 Then I'm going to write word underscore count dot get. 23:48.890 --> 23:55.640 And here I'm going to write word comma zero okay word comma zero. 23:55.640 --> 23:59.330 And then we are going to add it with one okay. 23:59.360 --> 24:06.000 So I'm using this get function which is available in the in the dictionary, as I have already shown 24:06.000 --> 24:06.330 you. 24:06.330 --> 24:08.880 And I will go and search for this specific word. 24:08.910 --> 24:09.510 Okay. 24:09.930 --> 24:12.990 Uh, if it is not present, then the value will be assigned to zero. 24:13.020 --> 24:15.000 Otherwise we are just going to increment with one. 24:15.030 --> 24:21.120 And we have already seen Dot get in our previous, uh videos when we discussed about dictionaries. 24:21.150 --> 24:24.990 And finally when once it does it, I'm just going to return my word count. 24:24.990 --> 24:29.580 And it needs to be with respect to this particular width right in the same line. 24:29.640 --> 24:33.150 Now let me just go ahead and call the function here. 24:33.150 --> 24:36.360 First of all I need to give my file path okay. 24:36.390 --> 24:37.830 File path is very simple. 24:37.830 --> 24:40.830 In the same working location I have sample dot txt file. 24:40.860 --> 24:42.150 So this is the same file. 24:42.150 --> 24:46.920 It is present in my uh same folder location that is functions. 24:46.920 --> 24:49.800 So I'm just going to go ahead and call this. 24:49.800 --> 24:51.990 Then I'm going to use word underscore. 24:51.990 --> 24:57.540 Frequency is equal to count underscore word underscore frequency. 24:57.540 --> 25:01.260 And then I'm just going to give the file path okay. 25:01.260 --> 25:03.490 So this will basically be my file path. 25:03.520 --> 25:08.380 Now after this, I will just go ahead and print the word frequency. 25:08.410 --> 25:10.060 Now see each and every thing is done. 25:10.150 --> 25:15.190 Let me execute and always make sure guys indentation is the main key thing many people may face problem 25:15.190 --> 25:16.720 if your indentation is not correct. 25:16.750 --> 25:22.750 Okay, so now if I go ahead and execute it cannot access local variable word where it is not associated 25:22.750 --> 25:23.560 with a value. 25:23.560 --> 25:27.070 So let's see where is the error. 25:27.070 --> 25:31.870 So word frequency of word uh frequency of file path. 25:32.110 --> 25:38.740 Um if I'm going inside this particular function inside this it is going to for words in word okay. 25:38.920 --> 25:39.370 Uh okay. 25:39.370 --> 25:40.570 It should be opposite. 25:40.600 --> 25:41.110 Okay. 25:41.140 --> 25:44.800 So I will just go ahead and write this because I have to access words. 25:44.800 --> 25:46.540 So here you can see hello is present. 25:46.540 --> 25:47.920 One word is present. 25:47.950 --> 25:49.240 Everything is present one. 25:49.270 --> 25:49.480 Okay. 25:49.510 --> 25:53.050 So let me just go ahead and save it and let me write again. 25:53.050 --> 25:53.890 Crush. 25:54.460 --> 25:54.700 Okay. 25:54.730 --> 25:56.080 So crush is present two times. 25:56.080 --> 25:59.140 So if I go ahead and execute I should be getting crush two times. 25:59.140 --> 26:05.160 So here is crush okay a simple example of a function to read a file and count the frequency of each 26:05.160 --> 26:05.490 word. 26:05.520 --> 26:09.540 So here we have taken a sample file, and we have read it in the read mode. 26:09.540 --> 26:11.460 And we have counted each and every word. 26:11.490 --> 26:15.030 Amazing function again and I hope you are learning many things out of it. 26:15.060 --> 26:18.540 Okay, more about the file operations we will be discussing. 26:18.540 --> 26:22.710 There is a separate section that will be coming up as we go ahead. 26:23.460 --> 26:25.590 Now final task. 26:25.650 --> 26:26.700 This is for you. 26:27.120 --> 26:29.580 Um, anyhow, I'll be giving you the code. 26:29.610 --> 26:33.030 Okay, so here, the question is very simple. 26:33.060 --> 26:34.800 You need to validate the email address. 26:34.830 --> 26:35.430 Okay. 26:35.430 --> 26:41.640 So let's say that you are there is a subscription, uh, emails that you really want to get from a company. 26:41.640 --> 26:46.590 Let's say there is a page and people will go ahead and write any email and just click on start subscription, 26:46.620 --> 26:49.440 right if they want the free materials or anything as such. 26:49.710 --> 26:53.790 Uh, now the problem is that someone may not put a valid email address. 26:53.790 --> 26:56.070 So we also need to do the valid email check. 26:56.070 --> 27:00.210 So for this I will already give you this particular code okay. 27:00.210 --> 27:04.180 And you can go ahead and try it out and just try to understand it. 27:04.210 --> 27:06.790 Here I've used every special characters okay. 27:06.820 --> 27:09.400 It should it should be matching this pattern. 27:09.400 --> 27:09.820 Right. 27:09.850 --> 27:16.240 Like let's say one of my email address is some username at the rate it can be gmail.com. 27:16.270 --> 27:16.540 Right. 27:16.540 --> 27:19.750 So similarly this is my first regular expression right. 27:19.750 --> 27:26.560 It can be between A to z capital E to z 0 to 9 plus uh then again add that it will be there again. 27:26.560 --> 27:30.610 You can have Gmail, you can have Hotmail, you can have Yahoo anything as such. 27:30.610 --> 27:32.170 And then finally.com. 27:32.170 --> 27:32.530 Right. 27:32.530 --> 27:39.220 So this will be the entire, uh, matching uh for the regular expression I will talk more about regular 27:39.220 --> 27:40.930 expression as I go ahead. 27:40.960 --> 27:43.660 Now if I go ahead and check this you will be able to see it. 27:43.690 --> 27:46.240 Here you can see this is my true email. 27:46.270 --> 27:47.440 And this is a valid email. 27:47.440 --> 27:48.370 This is not a valid email. 27:48.370 --> 27:50.560 So just go through this and check it out. 27:50.560 --> 27:55.480 Uh the reason why I'm including some new new things so that you get excited by just seeing all this 27:55.480 --> 27:56.710 kind of application. 27:56.710 --> 27:59.440 So I hope you like this particular video. 27:59.470 --> 28:01.090 Uh, this was it from my side. 28:01.090 --> 28:02.680 I will see you in the next video. 28:02.680 --> 28:03.070 Thank you.