1
00:00:05,240 --> 00:00:08,580
So it's a tradition, when learning any new programming language,

2
00:00:08,580 --> 00:00:12,520
that the first program you write should print out the text Hello World,

3
00:00:12,520 --> 00:00:14,740
and we're going to do just that in this video.

4
00:00:14,740 --> 00:00:21,520
So start Intellij DEA, as I have, and choose Create New Project from the Main menu.

5
00:00:21,520 --> 00:00:27,760
Now if you're using a different IDE or editor, use its command for creating a new Python project.

6
00:00:27,760 --> 00:00:31,160
So we want to select Python, on the left hand side, as I've done here,

7
00:00:31,160 --> 00:00:39,080
and also make sure you've got a valid Python SDK selected at the top right, and click on Next.

8
00:00:39,080 --> 00:00:42,940
Once you get to this screen, you can type in the project name.

9
00:00:42,940 --> 00:00:47,620
So I'm just going type in there, Hello World.

10
00:00:47,620 --> 00:00:52,020
Now I don't like using spaces in the names of things, as that can cause problems.

11
00:00:52,020 --> 00:00:54,940
To make the name more readable, I've used Pascal case.

12
00:00:54,940 --> 00:00:59,660
I've used a capital H for the word Hello, and W for the word World.

13
00:00:59,660 --> 00:01:05,840
Now you can change the location if you want, but make sure you don't put one project inside another project directory

14
00:01:05,840 --> 00:01:10,080
So what I'm going to do, and I'll fix up that spelling first,

15
00:01:10,080 --> 00:01:14,880
I'm going to move to a new folder, just to show you what you would do, the first time you're setting this up.

16
00:01:14,880 --> 00:01:16,680
Then come to the folder.

17
00:01:16,680 --> 00:01:19,780
That's my main folder where I've got all my different programming languages.

18
00:01:19,780 --> 00:01:22,640
I'm going to create a new project.

19
00:01:22,640 --> 00:01:23,560
I need folder, rather, and I'm going to call

20
00:01:23,560 --> 00:01:33,200
this one python-masterclass-remaster-shared, and this is just a format that I've used on my computer.

21
00:01:33,200 --> 00:01:37,260
Alright, so scrolling up here, i'm gonna do the same thing that I've done for my java masterclass.

22
00:01:37,260 --> 00:01:44,080
I'm gonna create a subfolder called current Java masterclass remaster, but we're going to obviously call that Python.

23
00:01:44,080 --> 00:01:47,500
And this is just the way that I've set things up:

24
00:01:47,500 --> 00:01:57,420
python-masterclass-remaster, and I think I called it current at the start, so I'll put that current,

25
00:01:57,420 --> 00:02:01,100
and that's where all my projects are going to go, in that folder.

26
00:02:01,100 --> 00:02:06,140
Now the first time you do that, you create a new folder. If we look at the end of this project location,

27
00:02:06,140 --> 00:02:08,340
note that it hasn't got the project name there.

28
00:02:08,340 --> 00:02:16,360
So what you'll need to do for the very first project, is put a slash in there, and HelloWorld, being the name of the project.

29
00:02:16,360 --> 00:02:21,040
Subsequent times that you create new projects, it'll automatically find this project location,

30
00:02:21,040 --> 00:02:23,060
and put the project name after it.

31
00:02:23,060 --> 00:02:27,480
Alright, so at this point now that I've done that, I'm going to click on Finish.

32
00:02:27,480 --> 00:02:29,860
You're prompted now, do we want to create that folder?

33
00:02:29,860 --> 00:02:35,880
This is, I know it's a long path, but this is the path that I'm storing my files on a network drive,  so for me that's valid.

34
00:02:35,880 --> 00:02:40,660
You would choose whichever folder you wanted to, and make sure that was valid and then click OK.

35
00:02:40,660 --> 00:02:43,640
At this point, IntelliJ is setting up the project.

36
00:02:43,640 --> 00:02:47,820
Now it won't take long but it's a good idea not to do anything until it's finished.

37
00:02:47,820 --> 00:02:51,360
So you can see the messages down there
in the status bar, at the bottom of the screen.

38
00:02:51,360 --> 00:02:58,000
Wait for these to disappear, and you'll see IntelliJ uploading skeletons, whatever that means, and indexing the project,

39
00:02:58,000 --> 00:03:06,740
and then the project's been built and we should see the project pane open, and we'll be able to see some files there.

40
00:03:06,740 --> 00:03:09,760
Alright, so you can see now the project
pane open. There's no more,

41
00:03:09,760 --> 00:03:13,300
well actually there is a bit, there's the updating skeletons message you can see down the bottom there.

42
00:03:13,300 --> 00:03:15,340
So we'll just give that a moment to finish.

43
00:03:15,340 --> 00:03:18,900
Once it's done that, we can get started.

44
00:03:18,900 --> 00:03:25,180
Alright, so you can see now it's finally finished. There's now no more working messages appearing in the status bar.

45
00:03:25,180 --> 00:03:29,040
So what we want to do is create a new file for our program.

46
00:03:29,040 --> 00:03:32,360
So you want to make sure the project pane is open and you can see it is there.

47
00:03:32,360 --> 00:03:35,480
If it wasn't, by the way, you can come over here and click on project,

48
00:03:35,480 --> 00:03:39,420
and that will open and close the project tab. So make sure that's open.

49
00:03:39,420 --> 00:03:42,840
So at the top of the project pane in bold,
is the name of our project.

50
00:03:42,840 --> 00:03:45,060
That's Hello World in this case.

51
00:03:45,060 --> 00:03:47,880
So make sure that you click on this, which I'm doing now,

52
00:03:47,880 --> 00:03:52,920
before we do the next step, and once we do that the file menu changes, depending on what you've got selected.

53
00:03:52,920 --> 00:03:56,120
So after clicking on the Hello World project, which I've just done,

54
00:03:56,120 --> 00:04:01,380
I can either right click and select New, Python File.

55
00:04:01,380 --> 00:04:07,300
Alternatively, I could come up here after selecting that and click on File, New, Python File.

56
00:04:07,300 --> 00:04:13,380
Either way will do the same thing. Okay, I'm going to call this one helloworld.

57
00:04:13,380 --> 00:04:16,399
Then note that I've typed it all in lowercase with no spaces.

58
00:04:16,399 --> 00:04:23,700
IntelliJ will automatically add the dot py extension to the file, which is what Python files typically have as their source file,

59
00:04:23,700 --> 00:04:28,940
but if your IDE or editor doesn't do that, then you would type in the full name, helloworld.py

60
00:04:28,940 --> 00:04:30,580
I'm gonna click on OK

61
00:04:30,580 --> 00:04:35,440
and we can see there in the project pane to the left, that it has been named with helloworld.py.

62
00:04:35,440 --> 00:04:39,400
So at this point we've now got a new Python file open in the editor.

63
00:04:39,400 --> 00:04:43,260
I'll talk a bit more about these files and directories in the project pane later.

64
00:04:43,260 --> 00:04:50,060
The best advice I can give at the moment, is that if you didn't create a file or a directory,  then don't mess with it.

65
00:04:50,060 --> 00:04:55,000
You'll get strange problems if you try and put anything in that
.idea directory, for example.

66
00:04:55,000 --> 00:05:00,240
The only thing we're interested in at the moment, are the .py files that we create,

67
00:05:00,240 --> 00:05:04,240
and obviously helloworld.py is the one that we've created for this project.

68
00:05:04,240 --> 00:05:10,560
And for the moment they should all be created inside, directly inside, the HelloWorld project structure,

69
00:05:10,560 --> 00:05:12,280
and that's what we've done here.

70
00:05:12,280 --> 00:05:17,160
Alright, so in terms of the actual code for our first program, it's extremely simple.

71
00:05:17,160 --> 00:05:24,040
We're going to come up and start typing print left parenthesis, noting that a right one gets added for us automatically,

72
00:05:24,040 --> 00:05:28,300
single quote, noting that a second single quote gets added automatically,

73
00:05:28,300 --> 00:05:33,340
and if you're using another IDE or editor, you'll need to perhaps enter those manually yourself.

74
00:05:33,340 --> 00:05:38,680
We're going to type Hello, World and an exclamation mark,

75
00:05:38,680 --> 00:05:41,820
and that's literally it. That's our first Python program.

76
00:05:41,820 --> 00:05:47,780
To run the program, we want to right click anywhere here in the editor window, which is where we've typed our code,

77
00:05:47,780 --> 00:05:52,160
right click and click on Run Helloworld.

78
00:05:52,160 --> 00:05:55,620
You can see straight away, the output appears in the run window at the bottom,

79
00:05:55,620 --> 00:05:58,560
and that's initially configured to be at the bottom of the screen,

80
00:05:58,560 --> 00:06:01,200
and we can see the output, Hello World!

81
00:06:01,200 --> 00:06:03,760
And that's our first Python program.

82
00:06:03,760 --> 00:06:08,820
Although it's very simple, our Hello World program does include a few important basics.

83
00:06:08,820 --> 00:06:12,240
Firstly, we've used the Python function print.

84
00:06:12,240 --> 00:06:14,140
Python has many functions,

85
00:06:14,140 --> 00:06:19,260
such as mathematical functions like round, to round the number of digits after the decimal point

86
00:06:19,260 --> 00:06:25,740
and char, chr and ord, to convert characters to their numeric representations and vice-versa,

87
00:06:25,740 --> 00:06:27,240
as well as many more.

88
00:06:27,240 --> 00:06:30,580
You can also define your own functions, as we'll see later.

89
00:06:30,580 --> 00:06:34,640
In the next video, we'll see more ways to use the print function.

90
00:06:34,640 --> 00:06:37,520
See you in the next video.