Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:00,030 --> 00:00:05,240 Hi, welcome again. In the previous lecture we were talking about numbers. 3 00:00:05,240 --> 00:00:11,370 Specifically we looked at integers and float data types so these are referred 5 00:00:11,370 --> 00:00:15,809 to as data types in Python, so integers and floats. In this lecture we're going 7 00:00:15,809 --> 00:00:23,970 to look at strings. I already mentioned strings in the previous lecture. 9 00:00:23,970 --> 00:00:30,410 So a string is everything that goes inside quotes. "Hi there". That is a string. 11 00:00:30,410 --> 00:00:40,170 And of course strings can be stored in variables and you can print those 13 00:00:40,170 --> 00:00:44,579 variables, so we're using the interactive shell now, but of course you can use a 15 00:00:44,579 --> 00:00:51,899 part of script as we did previously. So numbers were used to do math operations, 17 00:00:51,899 --> 00:00:58,070 but strings, strings are used for displaying information for the user. 19 00:00:58,070 --> 00:01:04,320 So let's say you have a web application, and you want to generate some text 21 00:01:04,320 --> 00:01:10,140 dynamically on the web page, so you'd use would use Python on the backend and 23 00:01:10,140 --> 00:01:18,509 Python would send strings to the HTML code and HTML would render the 25 00:01:18,509 --> 00:01:24,689 code on the web page basically that's the idea or if you want to create a 27 00:01:24,689 --> 00:01:31,229 notepad, an editor with Python such as Atom let's say, all these things you see 29 00:01:31,229 --> 00:01:37,170 here so my program.py selection file, so all this would be written as 31 00:01:37,170 --> 00:01:43,710 strings inside Python and then you display them on the interface using 33 00:01:43,710 --> 00:01:48,780 various functions, for instance if you want to display a string on the terminal 35 00:01:48,780 --> 00:01:57,030 you'd use the print function. Now strings have methods associated with them. What I 37 00:01:57,030 --> 00:02:04,079 mean with methods is let me go ahead and try out a method. Methods, for 39 00:02:04,079 --> 00:02:10,860 methods you need to use the dot notation. So you'd refer to the string which is 41 00:02:10,860 --> 00:02:15,760 string c in our case actually variable c, but the variable is holding 43 00:02:15,760 --> 00:02:24,750 the strings so it's the same as doing here dot, so let's do c dot, replace and 45 00:02:24,750 --> 00:02:33,910 what I want to replace is e with i. So I'm replacing, for string here I'm 47 00:02:33,910 --> 00:02:42,310 replacing letter e with later i and what that will do it will replace all 49 00:02:42,310 --> 00:02:50,620 the letters, all the occurrences of this letter in the string, so you'd ask where 51 00:02:50,620 --> 00:02:55,739 can we see these method? Well that's very easy actually. You can do dir and 53 00:02:55,739 --> 00:03:01,540 then pass the string there, any string. It could be c, it could be an empty string 55 00:03:01,540 --> 00:03:07,930 or whatever and that will print out all the available methods that you can use 57 00:03:07,930 --> 00:03:16,630 with strings, so let's say c dot upper. That will cover the strings to 59 00:03:16,630 --> 00:03:22,630 upper case letters. Now if you want to know what these methods are about you 61 00:03:22,630 --> 00:03:29,380 could ask for help. Just do help and then c, so the 63 00:03:29,380 --> 00:03:40,810 string or just empty string dot 65 00:03:44,320 --> 00:03:52,450 here replace method of the string instance, so string is like the blueprint 67 00:03:52,450 --> 00:03:58,560 that creates strings objects or you can say the data type that represents texts. 69 00:03:58,560 --> 00:04:08,950 Look here. Here is the syntax, so what you do is, you use a string like we did. 71 00:04:08,950 --> 00:04:16,840 So let's say here replace. Then you open brackets. Here is the old item you want 73 00:04:16,840 --> 00:04:24,490 to remove from the string and then the new item we want to replace it with i and 75 00:04:24,490 --> 00:04:30,140 then what you see here in square brackets, that means this parameter is 77 00:04:30,140 --> 00:04:35,330 optional so you can either pass it or not and you know in the previous case we 79 00:04:35,330 --> 00:04:42,100 didn't pass it so what Python did was it replaced all the occurrences of the i 81 00:04:42,100 --> 00:04:48,070 item but if you want to replace only the first occurrence you do one there and 83 00:04:48,070 --> 00:04:54,770 that will replace all the first i over the first e with i. That's how it works 85 00:04:54,770 --> 00:05:02,720 So strings, they support functions, so print is a function. Here. And they support 87 00:05:02,720 --> 00:05:08,530 methods like this one here and they also support operators so you get "Here" 89 00:05:08,530 --> 00:05:19,190 plus "There" and you get "HereThere" or you can make it more readable like that so 91 00:05:19,190 --> 00:05:23,930 an empty space is also a string and yeah that's about strings for now and I'll 93 00:05:23,930 --> 00:05:26,380 talk to you later. 5564