1 00:00:01,260 --> 00:00:06,420 How would you make a program that behaves like this? 2 00:00:06,450 --> 00:00:13,500 It asks you for your name and you put your name as a user, and the program will greet you, wLL output 3 00:00:13,560 --> 00:00:19,650 a message "Hello" and your name there, and also an exclamation mark at the end of the string. 4 00:00:19,650 --> 00:00:21,650 Well you do that with two things. 5 00:00:21,660 --> 00:00:28,440 First you need the input function to ask the user for input, to prompt the user for input and then you 6 00:00:28,440 --> 00:00:31,230 need string formatting. 7 00:00:31,230 --> 00:00:33,830 This is how string formatting looks like in Python. 8 00:00:35,020 --> 00:00:41,060 So in the first line, we are getting the user input, storing that input as a string in user input. 9 00:00:41,150 --> 00:00:48,620 Then we create a variable. In that variable, we will store the message we are constructing and this here 10 00:00:48,640 --> 00:00:51,210 is a string formatting expression. 11 00:00:51,340 --> 00:01:00,160 So we want to print out "Hello", and then have a space and then we want to print out the name of the user. 12 00:01:00,160 --> 00:01:09,000 So the value that the user inputs. This here, %s is a special string in Python, then we have 13 00:01:09,000 --> 00:01:13,950 an exclamation mark which is a normal string and the double quotes. 14 00:01:14,070 --> 00:01:15,630 So this is special here. 15 00:01:16,260 --> 00:01:23,670 And then after the string, you don't want to put a comma. What you want to do is use this percentage 16 00:01:23,730 --> 00:01:27,150 operator and then use a variable. 17 00:01:27,160 --> 00:01:33,450 Now the value of this variable will go and replace the %s. 18 00:01:33,500 --> 00:01:35,620 So what you get instead is "Hello" 19 00:01:35,670 --> 00:01:37,140 and your name there. 20 00:01:37,170 --> 00:01:43,980 Now, this method of string formatting by using this %s here and percentage operator in here, 21 00:01:44,230 --> 00:01:49,200 this is valid for Python 2 and Python 3 as well. 22 00:01:49,200 --> 00:01:53,680 Now there is another method that was introduced in Python 3.6. 23 00:01:53,940 --> 00:02:00,060 So the method I'll introduce now will not work if you run it with a Python version earlier than 24 00:02:00,060 --> 00:02:01,500 3.6. 25 00:02:01,500 --> 00:02:04,740 The method goes like this. 26 00:02:04,740 --> 00:02:12,750 Let's store the entire string in a variable again and so it will be a string with double quotes or single 27 00:02:12,750 --> 00:02:14,680 quotes whatever you prefer. 28 00:02:14,670 --> 00:02:22,770 I'm using double quotes, so "Hello", and you use these curly brackets and inside that you put the name 29 00:02:22,800 --> 00:02:31,350 of the variable which value you want to be put in this place. 30 00:02:31,350 --> 00:02:32,910 Now this is not all. 31 00:02:32,910 --> 00:02:40,400 So if I save these and execute the code and I say "Ardit", it will return the string. 32 00:02:40,400 --> 00:02:41,770 So we need to do something else. 33 00:02:42,030 --> 00:02:47,490 What we need to do is we need to add a prefix f just outside of the qoutes. 34 00:02:47,550 --> 00:02:48,820 So this is the string. 35 00:02:48,900 --> 00:02:51,240 This f goes outside of the quotes. 36 00:02:51,660 --> 00:03:00,950 If I save the script now, execute again, write my name, and now we get the expected output, note that 37 00:03:01,610 --> 00:03:04,250 we've got two variables with the same name here. 38 00:03:04,610 --> 00:03:09,950 And what it will happen is that the first Python executes a script from top to bottom so it executed 39 00:03:09,950 --> 00:03:12,560 the first line it executes the second line. 40 00:03:12,560 --> 00:03:23,450 So it will store "Hello Ardit" in the message variable, but then we are overwriting that variable. 41 00:03:23,450 --> 00:03:28,490 So in this case the string will be written in that message variable. 42 00:03:28,490 --> 00:03:33,530 So whatever you create in here, whatever object you store in here, in the variable that object will be 43 00:03:33,530 --> 00:03:37,550 the current object that that variable will refer to. 44 00:03:37,550 --> 00:03:43,430 So in this case here you will print out the object that you created in here which happens to be "Hello Ardit". 45 00:03:45,480 --> 00:03:46,720 Which one should you use? 46 00:03:46,740 --> 00:03:55,260 Well, if you think that your project is going to be run with Python 3.6 or above, then use this 47 00:03:55,650 --> 00:04:02,310 nicer version, it's more readable, if you think that your project, your python files will be run with 48 00:04:02,400 --> 00:04:09,660 Python 2 or 3.1, or 3.2, or 3.3, then you might want to opt in for this method because sometimes 49 00:04:09,660 --> 00:04:16,320 when you deploy your scripts in a server for example let's say you want to execute a script every day 50 00:04:16,350 --> 00:04:23,160 at the certain hour, you want to deploy it on a web server, and that's web server will have a specific 51 00:04:23,160 --> 00:04:24,700 version of Python. 52 00:04:24,720 --> 00:04:27,700 Sometimes that version is Python 2. 53 00:04:27,750 --> 00:04:34,890 So in that case you want to adjust your scripts so that it works with Python 2 and the web server, 54 00:04:34,890 --> 00:04:40,440 the server, the computer will run your script with a particular Python version. 55 00:04:40,440 --> 00:04:44,130 We're going to look at this later when we deploy the web apps. 56 00:04:44,550 --> 00:04:47,540 So for now these are the two methods of string formatting.