WEBVTT 00:01.470 --> 00:03.150 Hello and welcome back to the costs. 00:03.150 --> 00:11.160 So in the last sessions we already got in touch with String objects and now we we dig a bit deeper into 00:11.520 --> 00:13.130 the strings however. 00:13.440 --> 00:20.370 Also later in our real world projects then our focus is not on strings so we we keep it here as hard 00:20.370 --> 00:22.590 as possible. 00:22.590 --> 00:30.920 So at the end of the last session we transformed an integer five into a string by putting it into quotation 00:30.920 --> 00:32.140 marks. 00:32.180 --> 00:34.370 Let's repeat this again. 00:34.370 --> 00:41.090 So we are transforming into a five to a string and this completely changes the functionality of the 00:41.090 --> 00:41.660 object. 00:41.660 --> 00:44.360 So before five plus to give seven. 00:44.360 --> 00:54.740 And now if you execute this string five so represented by C plus two you get an error message. 00:54.740 --> 01:00.740 So it says it must be a string not an integer so it completely changes the functionality. 01:00.890 --> 01:02.900 But what other strings actually. 01:02.930 --> 01:08.040 Well strings up a sequence of Unicode characters inside a quotation mark. 01:08.660 --> 01:14.280 And this is treated like any other sequence like Lists Tuples which we see later. 01:14.280 --> 01:21.710 And yeah actually we can when we can put into a string many different characters like numbers letters 01:21.710 --> 01:27.170 special characters like question marks and exclamation marks and so on which you will see later. 01:27.200 --> 01:29.750 But before now let's start with. 01:29.750 --> 01:30.590 Just um. 01:30.590 --> 01:30.950 Yeah. 01:30.950 --> 01:38.240 Assigning or creating and string object Doc and assign the variable D. 01:38.870 --> 01:44.060 And also we create a string object cat and assign the right E. 01:45.110 --> 01:54.320 And no surprise if we print the types of DNA e both strings and if you tried to add both strings as 01:54.320 --> 01:59.410 before we tried to apply the plus operator let's see what we get here. 01:59.570 --> 02:05.350 So not Python does it just concatenate both strings so D plus E gets dark. 02:05.360 --> 02:11.590 Cat and if we might add E plus D we get cat dog. 02:11.600 --> 02:18.880 So it's just concatenate ing both strings and I yeah if you try to to a substrate you can. 02:18.890 --> 02:19.580 Error message. 02:19.580 --> 02:28.790 So minus the the minus operator is not the defined four strings and if you tried to multiply two strings 02:29.450 --> 02:31.970 we also get them error message. 02:32.600 --> 02:38.850 And if we tried to add uh let's say an integer to a string. 02:39.140 --> 02:40.050 That's awesome. 02:40.070 --> 02:47.960 Error message it doesn't work but if we transform our integer five into a string then of course we can 02:47.960 --> 02:55.810 add this string to another string like a cat or dog so we can talk five and it works. 02:55.820 --> 02:57.990 Also the other way around. 02:58.190 --> 03:06.680 So we get five dog and if you tried to multiply a string with an integer like five we get and string 03:06.680 --> 03:16.980 with a five times the copy of dog so we get talk talk talk talk dog so dark and times five is just concatenated 03:16.980 --> 03:22.580 ing five times talk and we can also do it the other way around and get the same result. 03:23.350 --> 03:26.330 So it doesn't matter if three times five four five times D. 03:26.620 --> 03:34.550 However if you transform the integer five to a string and try to multiply it with our string do you. 03:34.720 --> 03:40.560 Of course we get an error message and also we can concatenate many strings to one string. 03:40.560 --> 03:51.060 So for example we have the string I we the string half string 5 and the string docs and thought we get 03:51.060 --> 03:55.080 the statement I have five docs. 03:55.240 --> 03:59.010 So as you can see here we need the empty spaces here. 03:59.020 --> 04:07.750 If we forget these our sentence or our statement looks a bit a little bit unreadable. 04:07.750 --> 04:15.520 So Python can also handle spaces here and spaces can be part of a string so that s s quite comfortable 04:15.520 --> 04:16.930 here. 04:17.050 --> 04:20.740 What I would like to introduce here is string formatting. 04:20.890 --> 04:29.980 So we are assigning um the string docs to the variety of animal and the integer 6 to amount and then 04:29.980 --> 04:31.500 we print the statement. 04:32.020 --> 04:42.350 I have curly brackets curly brackets dot end of the quotes and then I apply it to the string the method 04:42.620 --> 04:49.580 format and insides of the brackets a format I'm I'm defining for which the curly brackets are place 04:49.580 --> 04:56.610 holders so undefined execute the cell here I get I have five docs. 04:56.810 --> 05:00.780 So what the method dot format actually does is that the. 05:00.810 --> 05:07.040 Yeah it fits the place holders um in the sequence as defined within the brackets here. 05:07.070 --> 05:13.760 So so the first curly bracket will be replaced by the amount and the second curly bracket will be replaced 05:13.760 --> 05:14.830 by animal. 05:15.050 --> 05:16.940 And uh yeah for example. 05:16.960 --> 05:19.460 So yesterday I had six docs. 05:19.520 --> 05:25.590 Now today I have not docs but cards and not six. 05:25.670 --> 05:34.830 But let's say eight I updated I got I have eight kids and this is quite helpful actually if you had 05:34.980 --> 05:41.610 your variables are changing many times and you want to automate your statement how many cards or talks 05:41.610 --> 05:43.610 you have currently. 05:43.620 --> 05:45.800 So that's that's quite helpful here. 05:45.950 --> 05:51.170 What you can also do you can delete a whole string by calling the DL function. 05:51.180 --> 06:03.950 So inside the brackets you put the object D so D stands for dark and if you deleted so if you then tried 06:03.950 --> 06:09.010 to print the so pretty is not defined here it says. 06:09.110 --> 06:19.250 So now we have to redefine DIA again in order D again OK dark before I mentioned that a string is a 06:19.250 --> 06:26.240 sequence of Unicode characters and um yeah you by calling the line function you can count the numbers 06:26.240 --> 06:36.180 of items in a string so with these we would expect three items d o a.. 06:36.180 --> 06:37.110 All right. 06:37.110 --> 06:45.010 And we can also count the number of items or the number of characters and statement it's 40 and so let's 06:45.010 --> 06:47.640 go back to our statement. 06:48.430 --> 06:50.750 So our statement is I have five talks. 06:51.280 --> 06:55.000 So when we count we have to count actually all characters. 06:55.020 --> 06:56.660 So also the space character. 06:56.680 --> 07:08.080 So one two three four five six seven eight nine ten eleven twelve thirteen and also the DOT 14 characters. 07:08.080 --> 07:09.710 So that is correct here. 07:09.970 --> 07:16.540 And before we set different data types have different functionality so we could call the length length 07:16.540 --> 07:21.730 function on strings but we cannot call the length function on integers or floats. 07:21.730 --> 07:24.600 If you tried to do so you get an error message. 07:24.640 --> 07:32.450 So object type Integer has no length function or the length function is not defined and earlier we saw 07:32.450 --> 07:39.450 that integers and floats they have built in methods attributes and this holds also true for String object. 07:39.470 --> 07:47.270 So seeing objects also have predefined appeared in methods and attributes and one of this is uh the 07:47.360 --> 07:57.540 upper method and it's execute the upper method on our String objects statement and that s print statement. 08:02.090 --> 08:07.990 Now you can see all items all our characters are converted to uppercase. 08:08.120 --> 08:11.780 So what actually the upper method does that just. 08:12.010 --> 08:12.630 Yeah. 08:12.770 --> 08:20.970 It converts all characters to the uppercase and we can also call the opposite method. 08:21.010 --> 08:24.850 Dot lower if we do so we get. 08:24.850 --> 08:28.070 I have talked some here we can see all characters are. 08:28.160 --> 08:28.390 Yeah. 08:28.420 --> 08:30.140 Lowercase and s. 08:30.160 --> 08:32.280 Another method called capitalize. 08:32.290 --> 08:38.520 And if we call this method on statement we get I have talks but the. 08:38.620 --> 08:40.870 I hear you see is capitalized. 08:40.900 --> 08:47.690 So the first character in our string is capitalized with them the capitalized method and there are many 08:47.690 --> 08:51.300 more build and methods for String objects. 08:51.440 --> 08:59.550 And if you like you can look at the documentation or just press the dots tab to see what pace and office 08:59.550 --> 09:07.580 here and I can just try out what what happens if you call the the method then then the and attributes 09:07.580 --> 09:07.880 here 09:10.730 --> 09:18.650 but for now we are finished here with the strings and we head over to lists and s some function call 09:18.680 --> 09:24.980 list which tree app transforms a string object into a list so we can try. 09:25.130 --> 09:27.020 What happens here. 09:27.110 --> 09:34.150 So our statement is I have five docs and we transform it into a list and what we can see here. 09:34.160 --> 09:42.600 We have all single characters separated by a comma inside craft bracket brackets and this is called 09:42.600 --> 09:43.040 The List. 09:43.040 --> 09:50.270 So if you check the type type l This is a list and then the next lesson we will have a deeper look. 09:50.270 --> 09:51.960 To to the list object. 09:51.990 --> 09:54.100 But so for the time being. 09:54.140 --> 09:54.900 This is it. 09:54.920 --> 09:55.580 And the. 09:55.620 --> 09:55.880 Yeah. 09:55.880 --> 09:56.620 Hope you enjoyed it. 09:56.630 --> 09:58.010 And see you in the next session.