WEBVTT 00:02.340 --> 00:07.680 Hello and welcome back to the costs on the last session we learned about basic data types like integers 00:07.740 --> 00:09.390 floats and strings. 00:09.690 --> 00:16.000 And also we learned about basic operations like addition multiplication and so on. 00:16.000 --> 00:19.710 And now in this session we are introducing where I was. 00:20.370 --> 00:22.020 So what is the variety. 00:22.050 --> 00:26.590 Let's assume we have an immediate object five. 00:26.760 --> 00:36.120 We can print it out and instead of having the five as the number itself we can assign a variety of let's 00:36.120 --> 00:37.470 call it a. 00:37.540 --> 00:38.900 So a equals five 00:41.760 --> 00:49.940 in Python now makes internally a reference that whenever we call a meets calculating five for its its 00:49.960 --> 00:50.860 returning five. 00:50.860 --> 00:54.730 So if we now just print a we are getting five. 00:55.000 --> 00:58.000 So A stands for five. 00:58.720 --> 01:04.930 And as we learned in the last session we can also print out a by calling the print function. 01:05.050 --> 01:14.290 So that's actually the same and we can also change the reference so if we say OK if I was five but now 01:14.320 --> 01:17.800 a seven we can just change it. 01:17.800 --> 01:22.680 So a seven and let's check if A's now seven and eight seven now. 01:22.690 --> 01:30.930 So we can simply change our reference so before our reference was to five to the integer object five 01:30.950 --> 01:32.970 and now a reference is to seven. 01:32.980 --> 01:37.350 So we can change for the reference all right. 01:37.370 --> 01:49.620 So let's introduce another variable let's call it B B equals 2 and we can also print out b b as to and 01:49.640 --> 01:55.730 then the last lesson we have learned that if you want to print out both A and B and one cell 01:59.180 --> 02:05.940 so by default to put a notebook only print out the last statement or the last line that's B here. 02:05.940 --> 02:09.930 So now if you want to print out both we have to call the print function 02:12.970 --> 02:15.480 and A and B. 02:16.480 --> 02:20.160 So now we can print out both 7 and 2. 02:20.570 --> 02:20.890 All right. 02:20.900 --> 02:26.870 So basically we can do with varietals the same as with integers or floats. 02:27.020 --> 02:41.770 We can do the basic operations like additions so we can take a plus b s nine A minus B S five B minus 02:41.860 --> 02:53.800 a minus five B can also multiply so A times B and we can of course we can also divide a divided by B 02:57.820 --> 03:02.830 and 0 for example we can assign the result of a divided by B 03:05.960 --> 03:10.430 so it's three point five we kind of can assign a new override but see to it. 03:10.850 --> 03:13.170 So C equals a divided by B. 03:14.300 --> 03:21.000 Let's print out C So c is three point five and we can also check the data type of C. 03:21.390 --> 03:24.880 So I would expect that it's a float. 03:25.020 --> 03:27.770 Yes exactly. 03:28.020 --> 03:33.560 And of course we cannot only assign over either to an integer or an end and float. 03:33.570 --> 03:37.050 We can also assign a rival to an end String object. 03:37.050 --> 03:47.260 So for example we have dark and we can assign the right of a d d equals stock and we can of course print 03:47.260 --> 03:48.430 out D so D. 03:48.850 --> 03:55.750 So internally a person makes a reference from the right a deed to our string object talk. 03:55.840 --> 04:01.530 So these stock and we can also check the data type of D. 04:03.120 --> 04:10.350 And it's a string so dark dog is a string of costs and the idea's referencing to talk and there's also 04:10.350 --> 04:17.700 a string then and former Ibo name we can actually make any name we we we want to have so we can say 04:18.270 --> 04:30.170 my favorite dog is Lassie for example and this works. 04:30.200 --> 04:39.140 Now if I want to print out my variable my favorite dog I can start typing my end by pressing the tab 04:39.170 --> 04:39.680 key. 04:41.300 --> 04:48.930 Supplies and automatically completes my where I ever saw my wife Leslie is oh that's called the tab 04:48.950 --> 04:51.940 completion supplies. 04:52.010 --> 04:55.150 Knows that a variable caught my favorite dog is start. 04:55.170 --> 05:04.090 Um yeah internally and whenever I start typing my then I can press tap and um yeah Python automatically 05:04.110 --> 05:07.420 um yeah completes my my arrival. 05:07.430 --> 05:11.320 So that's that's quite helpful actually when when the rivals. 05:11.320 --> 05:17.600 This is quite long like here in that case and I what I would also like to highlight this and that I 05:17.600 --> 05:19.510 need the under slash here. 05:19.520 --> 05:25.670 So if it's just a space my favorite dog so that's that cannot serve as a rival. 05:25.670 --> 05:29.470 So here it gives me an error message. 05:29.750 --> 05:36.150 So space space is not defined as us as part of a rival actually. 05:36.260 --> 05:37.700 So the only works in this way 05:43.740 --> 05:51.990 and also a string itself like let's say Doc a string like DA cannot be in our arrival so dark equals 05:52.080 --> 05:52.650 Spike 05:56.250 --> 05:58.830 gets me as well and an error message. 06:00.330 --> 06:03.060 N on into da float cannot be in viable. 06:03.070 --> 06:14.920 So let's say 5 equals Spike let's say it also doesn't work but an integer can be part often variety. 06:14.970 --> 06:19.840 So let's say dark 5 is a spike. 06:20.490 --> 06:21.270 So that works 06:27.850 --> 06:30.120 and that's one last thing I want to highlight here. 06:30.130 --> 06:35.590 So let's assume I assign to the variable E equals 10 06:38.960 --> 06:55.680 so we use 10 and then I assign F equals E Oh sorry F equals E sum this case f is 10 because E M and 06:55.680 --> 06:59.370 F equals E so f also must be 10. 06:59.700 --> 07:01.940 And now if I change E. 07:01.950 --> 07:07.380 So before you reference was a reference to the object 10. 07:07.620 --> 07:17.990 If I change e to let's say 15 and I again check the reference of F F is 13. 07:18.030 --> 07:21.360 Even if I before I referenced F equals E. 07:21.390 --> 07:28.150 So what happened internally so internally here and not object 10 was created and then reference. 07:28.260 --> 07:37.300 And it was reference to the variable e and here and we say F equals E then internally a reference to 07:37.300 --> 07:45.160 the same object 10 was created to F so we have one object an integer 10 and we have two references from 07:45.160 --> 07:54.880 tend to we and 2 F and if you change here the reference to 15 internally a new object 15 is created 07:55.120 --> 08:03.380 and the reference for you was changed from 10 to 15 but there was no impact on F so the reference from 08:03.380 --> 08:09.890 F is still to the integer object 10 not to 15 so that's that's quite important to understand due out 08:10.300 --> 08:13.780 how Python works internally all right. 08:13.800 --> 08:15.320 So that's it. 08:15.390 --> 08:16.650 So thank you very much. 08:16.650 --> 08:17.700 And um yeah. 08:17.700 --> 08:18.670 Hope you enjoyed it. 08:18.700 --> 08:20.310 And uh see you in the next lesson.