WEBVTT 00:00.320 --> 00:00.980 Hello guys. 00:00.980 --> 00:03.470 So we are going to continue the discussion with respect to Python. 00:03.470 --> 00:06.890 And in this video we are going to discuss about filter function. 00:06.920 --> 00:08.780 Now what exactly is filter function. 00:08.780 --> 00:14.600 So filter function constructs an iterator from elements of an iterable for which a function returns 00:14.600 --> 00:15.170 true. 00:15.200 --> 00:19.280 It is used to filter out items from a list based on a condition. 00:19.280 --> 00:26.120 So finally, just to understand what this filter function do, it is used to filter out items from a 00:26.120 --> 00:29.300 list or any iterable based on a condition. 00:29.330 --> 00:35.090 Okay, so in order to make you understand, let me just go ahead and quickly, uh, write a code for 00:35.090 --> 00:35.420 you. 00:35.420 --> 00:37.790 So here I'm going to create a definition. 00:37.790 --> 00:43.730 Let's say this is my function which will tell whether a number is, uh, even or odd. 00:43.760 --> 00:44.000 Right. 00:44.030 --> 00:48.470 Or let's say this particular number is just this function is just going to check whether the number 00:48.470 --> 00:50.600 is even and it is just going to return true or false. 00:50.600 --> 00:52.880 So here if I am giving num okay. 00:52.910 --> 00:55.880 And let's say that I'm going to write my condition. 00:55.880 --> 01:00.740 If num percentile two is double equal to zero, then what we are going to do we are just going to return 01:00.760 --> 01:01.270 True. 01:01.300 --> 01:01.750 Right. 01:01.750 --> 01:02.680 So perfect. 01:02.680 --> 01:03.940 This works absolutely fine. 01:03.940 --> 01:05.770 We have seen this kind of function a lot. 01:05.770 --> 01:08.230 So now if I just go ahead and give my 24. 01:08.230 --> 01:12.070 So it is just going to give me true because this is obviously a true number. 01:12.460 --> 01:16.750 But let's say that now I have a list of elements. 01:16.750 --> 01:21.670 And here I have like 123456789 ten something like this. 01:21.880 --> 01:29.350 1112 okay, now I want to apply the same operation on top of this particular element. 01:29.350 --> 01:34.930 And I want to just filter out which satisfies only this specific condition. 01:34.960 --> 01:35.380 Right. 01:35.380 --> 01:37.540 So now focus on the last statement. 01:37.540 --> 01:41.620 It is used to filter out items from a list based on a condition. 01:41.650 --> 01:42.160 Right. 01:42.160 --> 01:46.090 So this is my condition and I want to filter out from this specific list. 01:46.120 --> 01:46.600 Right. 01:46.600 --> 01:47.770 So how do I do it. 01:47.800 --> 01:48.880 Yes, I can actually do it. 01:48.880 --> 01:52.270 I can just iterate through all this particular elements inside this even function. 01:52.270 --> 01:54.580 And then I should be able to do it right. 01:54.580 --> 01:59.170 I should be able to get true, you know, probably append it in another list and get the values. 01:59.170 --> 02:02.220 But let's do this with the help of filter. 02:02.280 --> 02:04.140 Okay, now in filter. 02:04.770 --> 02:07.110 If if you know about filter, right. 02:07.140 --> 02:10.470 Filter usually takes first parameter as again function. 02:10.470 --> 02:12.840 So in this case even is my function. 02:12.840 --> 02:15.510 And the second parameter will be my list okay. 02:16.440 --> 02:21.420 Now what this filter does is that whatever condition I have written inside this particular function 02:21.420 --> 02:27.300 only that will get applied into this and the elements will be taken from the list only which satisfies 02:27.300 --> 02:28.410 this condition. 02:28.440 --> 02:28.800 Right? 02:28.800 --> 02:32.010 Which is returning true, only that elements will be taken out. 02:32.040 --> 02:32.370 Okay. 02:32.400 --> 02:35.280 So here when I say filter even off list. 02:35.280 --> 02:41.130 And let me just go ahead and probably convert this into a list, you will be able to see that I will 02:41.160 --> 02:44.850 be getting all the elements that are only even right. 02:44.880 --> 02:50.160 So this is a basic example to understand about filter function, right. 02:50.160 --> 02:54.510 So it applies a kind of filter on the list that we specifically have. 02:54.540 --> 02:54.960 Okay. 02:54.990 --> 02:57.210 A very easy uh with respect to this. 02:57.210 --> 02:59.550 Now let's go ahead and see more examples. 02:59.550 --> 03:02.890 And this time I'm going to take filter with a lambda function. 03:03.040 --> 03:03.550 Okay. 03:03.550 --> 03:06.610 So lambda function and I will try to use the same thing. 03:06.610 --> 03:10.660 Or let me just use some other things like let's say this is my number variable. 03:10.660 --> 03:14.770 I have like 123456789 okay. 03:14.770 --> 03:21.850 And then I will say hey do a filter and try to just take out greater than five okay. 03:22.000 --> 03:24.010 Greater than five okay. 03:24.040 --> 03:25.840 Try to create a filter, something like that. 03:25.840 --> 03:28.960 From this particular list I should only get numbers that are greater than five. 03:28.960 --> 03:31.210 So now I will just go ahead and write list. 03:31.240 --> 03:33.610 I will go ahead and use filter function. 03:33.640 --> 03:35.800 And let me just go ahead and define my lambda function. 03:35.800 --> 03:37.870 Write Lambda function will be very simple. 03:37.870 --> 03:43.150 If I go ahead and write just lambda expression this will this will be my argument. 03:43.180 --> 03:43.780 Oh, sorry. 03:43.810 --> 03:44.620 Uh, yes. 03:44.650 --> 03:45.250 Argument. 03:45.250 --> 03:46.960 And I'll be writing my expression. 03:46.960 --> 03:53.800 That is x is greater than five and on which list I will basically apply this entire thing in my numbers. 03:53.830 --> 03:54.010 Right. 03:54.040 --> 03:57.580 So this entire function is going to get applied on this particular list. 03:57.610 --> 04:03.180 Now once I go ahead and print it you will you'll be able to see that I will only be getting the elements 04:03.210 --> 04:04.230 greater than five. 04:04.260 --> 04:04.620 Right. 04:04.650 --> 04:07.350 So this is one amazing thing with respect to list. 04:07.350 --> 04:12.420 And here with a simple just logic how you are able to use filter. 04:12.450 --> 04:15.480 Even in the previous video we saw about Lambda also. 04:15.510 --> 04:21.270 Now I will show you filter operation with uh with multiple condition. 04:21.300 --> 04:21.570 Okay. 04:21.600 --> 04:24.990 So here I'm going to say filter with a lambda function. 04:25.440 --> 04:28.800 Lambda function and multiple conditions. 04:28.800 --> 04:32.520 So just to make you understand that what all things are possible. 04:32.550 --> 04:33.120 Okay. 04:33.120 --> 04:39.360 So multiple conditions now as usual I'll take this numbers okay. 04:39.990 --> 04:40.710 Right. 04:40.710 --> 04:44.730 And let's say I will write a variable even. 04:44.730 --> 04:48.030 And it should be even I'm writing two check okay. 04:48.060 --> 04:50.610 Even and greater than five. 04:50.640 --> 04:50.880 Okay. 04:50.880 --> 04:53.280 So this is my variable that I'm actually going to create. 04:53.310 --> 04:54.900 Two things I'm actually doing over here. 04:54.930 --> 04:57.420 First of all I will check whether the number is even or not. 04:57.420 --> 05:01.130 Will filter out based on the number is even or not, and it should be greater than five. 05:01.160 --> 05:03.320 So in this I will again use list. 05:03.350 --> 05:05.030 I will again use filter. 05:05.060 --> 05:05.600 Okay. 05:05.600 --> 05:11.600 And along with that I will use my lambda x x colon greater than five okay. 05:11.630 --> 05:13.100 So this is my one condition. 05:13.100 --> 05:15.020 And I will go ahead and use one logical. 05:15.020 --> 05:20.420 And so and operation over here I will use and this will be x percentile two or modulus two is double 05:20.420 --> 05:20.990 equal to zero. 05:20.990 --> 05:22.640 So these are my two conditions. 05:22.640 --> 05:23.900 If it is getting satisfied. 05:23.900 --> 05:28.070 And this will get applied to all my numbers list of numbers that is available over here. 05:28.070 --> 05:31.640 So inside this lambda function what we are doing we are applying two expression. 05:31.640 --> 05:38.030 One is x is greater than five and the other one is x modulus two r is double equal to zero. 05:38.060 --> 05:40.100 Right now if I go ahead and print. 05:40.100 --> 05:41.090 So what it is going to do. 05:41.120 --> 05:45.440 First of all it is going to check whether it is even or not and then whether it is greater than five. 05:45.440 --> 05:50.150 So out of this elements you will be able to see that I am able to get only six and eight remaining. 05:50.150 --> 05:52.460 All elements are odd or less than five. 05:52.580 --> 05:53.330 Perfect. 05:53.360 --> 05:57.470 Uh, let's go ahead and see one more way of doing this. 05:57.500 --> 05:57.980 Okay. 05:58.010 --> 06:03.340 Now let's say that I want to apply a filter operation not only on list, let's say on dictionaries. 06:03.370 --> 06:07.060 Okay, so here I will just go ahead and do this. 06:07.090 --> 06:07.510 Okay. 06:07.540 --> 06:19.780 I will say hey apply filter to check if the age is greater than 25 in dictionary. 06:20.260 --> 06:20.920 Okay. 06:21.280 --> 06:25.810 So here you can basically see I will just create some data. 06:25.810 --> 06:27.940 And again I have already created this kind of data. 06:27.940 --> 06:35.410 So let me see from my which functions map function I think I have actually used this kind of data. 06:35.650 --> 06:36.610 Uh yeah. 06:36.610 --> 06:39.070 So this is my people data. 06:39.100 --> 06:39.280 Okay. 06:39.310 --> 06:41.230 So here I have specifically people data. 06:41.260 --> 06:42.820 I will use this same thing. 06:43.990 --> 06:44.560 Okay. 06:45.400 --> 06:47.470 Just trying to save time. 06:47.500 --> 06:48.040 Okay. 06:48.070 --> 06:56.020 Now from this I will create a function where I will say age greater than 25. 06:56.050 --> 06:56.620 Okay. 06:56.620 --> 07:03.920 And, uh, let's say I will just make some more data over here, I will copy, I'll put over here. 07:03.950 --> 07:05.300 I'll say Jack. 07:05.330 --> 07:10.100 Then along with this, I'll say John, age will be 25. 07:10.130 --> 07:10.670 Okay. 07:10.790 --> 07:14.660 And then what we are going to basically do, we are going to create a function here. 07:14.660 --> 07:18.560 We are going to give the person information, one item person information. 07:18.560 --> 07:22.850 And then we are just going to return the person of age. 07:22.850 --> 07:23.720 Right. 07:23.720 --> 07:29.060 And this age should be greater than 25. 07:29.150 --> 07:31.820 And based on this either it will return true or false. 07:31.850 --> 07:35.600 Right now we are just going to apply this with the help of filter. 07:35.600 --> 07:37.970 And we will use this particular function. 07:37.970 --> 07:45.110 So I will say filter and this will be my age greater than 25 along with my people because I need to 07:45.110 --> 07:51.440 apply this on my entire um uh, what to say collection that is iterable. 07:51.440 --> 07:53.510 And then I'll try to convert this into a list. 07:53.510 --> 07:54.830 So if I go ahead and print it. 07:54.830 --> 08:01.060 So here you will be able to see name age age 32 and 33 because this particular condition checks only 08:01.060 --> 08:04.840 and returns only the age based on the age condition greater than 25. 08:04.870 --> 08:06.730 It will return those specific records. 08:06.730 --> 08:10.930 And yes, from this particular filter operation, you will be able to see that I'm able to do this. 08:10.960 --> 08:11.320 Right. 08:11.320 --> 08:14.350 So these are some of the amazing operations that you can do with filter. 08:14.380 --> 08:16.960 So I would definitely try to put some kind of conclusions. 08:16.960 --> 08:21.730 And I'm doing that particular thing with respect to every video that I record in this. 08:21.730 --> 08:24.820 So here these are some of the conclusions. 08:25.300 --> 08:29.740 So here you can see the filter function is a powerful tool for creating iterators that filter items 08:29.740 --> 08:31.960 out of an iterable based on a function. 08:31.960 --> 08:35.860 It is commonly used for data cleaning filter objects and removing unwanted elements. 08:36.100 --> 08:40.000 By mastering filter, you can write more concise and efficient code for processing and manipulating 08:40.000 --> 08:41.140 collections in Python. 08:41.140 --> 08:43.150 So yes, this was about filter. 08:43.180 --> 08:48.100 Now as we go ahead, we will be discussing about and again we will be reusing all these things. 08:48.100 --> 08:51.160 But I think you got a clear idea about functions. 08:51.160 --> 08:52.300 Different types of functions. 08:52.300 --> 08:55.720 Anonymous function Lambda function maps function filter function. 08:56.110 --> 08:57.760 Uh, so yes, this was it from my side. 08:57.760 --> 08:59.560 I will see you all in the next video. 08:59.560 --> 09:00.100 Thank you. 09:00.130 --> 09:00.430 Take care.