1 00:00:05,200 --> 00:00:08,400 In this video, we're going to have a quick look at how files and directories 2 00:00:08,400 --> 00:00:13,360 are stored on your computer's hard drive. There's nothing complicated in this video. 3 00:00:13,360 --> 00:00:17,600 If you already know about file paths, you may want to skip it, and the next two videos, 4 00:00:17,600 --> 00:00:21,840 and move on to the Text files video. I'm using a Windows computer to record 5 00:00:21,840 --> 00:00:27,625 these videos. Most students are running Windows, which is why I'm using it. 6 00:00:28,320 --> 00:00:33,760 If you're using a Mac, or a Linux computer, there are two main differences you need to be aware of. 7 00:00:33,760 --> 00:00:38,640 The first is that Windows uses drive letters. Linux and Mac OS don't. 8 00:00:38,640 --> 00:00:42,240 If you're not using Windows, you can ignore drive letters. 9 00:00:42,240 --> 00:00:46,880 Each drive, on Mac OS or Linux, is mounted and appears as a directory. 10 00:00:46,880 --> 00:00:49,578 So what are drive letters? 11 00:00:51,360 --> 00:00:54,960 It's common to have more than one disk drive connected to your computer. 12 00:00:54,960 --> 00:00:59,520 That may seem like a strange thing to say, when many computers only come with one disk drive, 13 00:00:59,520 --> 00:01:04,000 but consider what happens when you plug a USB drive or memory stick into your computer. 14 00:01:04,000 --> 00:01:07,200 Once your operating system has recognised the USB device, 15 00:01:07,200 --> 00:01:11,280 it behaves like a separate disk drive. On Linux or Mac OS, 16 00:01:11,280 --> 00:01:16,289 the external device will appear as a folder. Windows doesn't work like that. 17 00:01:16,289 --> 00:01:22,974 I'll fire up the Windows file manager, called File Explorer, to show how Windows uses drive letters. 18 00:01:23,760 --> 00:01:30,160 Ok, this is the Windows file manager. In many ways, for programmers, it's hideous! 19 00:01:30,160 --> 00:01:33,200 Microsoft have tried to make it as easy to use as possible, 20 00:01:33,200 --> 00:01:38,960 for people who don't know much about computers. To a large extent, they've succeeded. 21 00:01:38,960 --> 00:01:41,840 If you're still watching this video, then you've probably been using your 22 00:01:41,840 --> 00:01:46,272 computer quite happily, without knowing about drive letters and file paths. 23 00:01:46,272 --> 00:01:51,471 At the top of the File Explorer window, we have a set of Frequent Folders. 24 00:01:52,880 --> 00:01:57,280 These are the folders that Windows has noticed you use most often. They include things like 25 00:01:57,280 --> 00:02:02,800 your Downloads and Documents folders. You might also have your IntelliJ projects folder there. 26 00:02:02,800 --> 00:02:07,520 As you can see, a lot of the folders I frequently use, on this computer, are related 27 00:02:07,520 --> 00:02:13,520 to my Python and Java courses. My Downloads folder is in there, and so is my Desktop. 28 00:02:13,520 --> 00:02:18,800 The exact contents will change, as Windows notices you frequently using certain folders. 29 00:02:18,800 --> 00:02:23,520 All of this is intended to shield people from having to understand file paths. You put your 30 00:02:23,520 --> 00:02:29,267 documents in Documents. What could be simpler? But we're no longer average users. 31 00:02:29,267 --> 00:02:33,599 We need to understand what's really happening, and where these directories really are. 32 00:02:33,599 --> 00:02:38,400 If you're not using Windows, keep watching. Windows is still the most popular operating 33 00:02:38,400 --> 00:02:43,075 system out there, and you will want to make sure that your code runs correctly on Windows. 34 00:02:43,280 --> 00:02:46,960 Over on the left, we have a list of the directories on my computer. 35 00:02:46,960 --> 00:02:52,000 Once again, that's been simplified. The first section is labelled Quick access, 36 00:02:52,000 --> 00:02:55,979 and contains the same directories as the Frequent folders list on the right. 37 00:02:56,080 --> 00:03:00,560 Where it gets interesting, is when we view the real directory structure. Scrolling down 38 00:03:00,560 --> 00:03:05,920 through the This PC list, on the left, we can see the disk drives connected to my computer. 39 00:03:05,920 --> 00:03:09,718 The first entry we're interested in is the Local Disk C. 40 00:03:10,640 --> 00:03:14,880 Drive C is the default drive on Windows computers. That's where Windows itself 41 00:03:14,880 --> 00:03:19,040 is normally installed, and also where all your files will probably end up. 42 00:03:19,040 --> 00:03:23,040 The reason why it's "C", rather than "A", is because drives "A" 43 00:03:23,040 --> 00:03:26,400 and "B" are reserved for removable floppy disks. 44 00:03:26,400 --> 00:03:30,640 Floppy disks aren't used these days, but in the days before hard disk drives, 45 00:03:30,640 --> 00:03:36,640 we used to store our files on removable disks, that could store up to 1.4 megabytes of data. 46 00:03:36,640 --> 00:03:42,480 Yes, you heard that right. 1.4 megabytes was considered a lot of storage back then! 47 00:03:42,480 --> 00:03:45,520 A selfie taken on a modern mobile phone could be bigger than that, 48 00:03:45,520 --> 00:03:49,534 but 30 years ago, one megabyte was large! 49 00:03:50,320 --> 00:03:54,080 Ok, that's why the first hard drive is called Drive C. 50 00:03:54,080 --> 00:03:59,920 On your computer, that may be the only drive shown. On my computer, I also have a Drive Y, 51 00:03:59,920 --> 00:04:02,640 and a few network drives. So on Windows, 52 00:04:02,640 --> 00:04:08,560 each disk drive is given a drive letter. On Mac OS or Linux, drive letters aren't used. 53 00:04:08,560 --> 00:04:13,842 That's the first difference between paths on those operating systems, and paths on Windows. 54 00:04:13,842 --> 00:04:17,440 I'll come to the second difference, when we look at file paths. 55 00:04:17,440 --> 00:04:22,339 Let's have a look at what's on my Drive Y. You probably won't have a Drive Y on your computer. 56 00:04:22,339 --> 00:04:26,917 Don't worry, this is one of those videos where you won't be following along at first. 57 00:04:26,917 --> 00:04:32,160 Just watch, and make notes about what I'm explaining. I've only got one directory on that drive, 58 00:04:32,160 --> 00:04:35,600 a directory called current-python-masterclass-remaster. 59 00:04:35,600 --> 00:04:39,389 That's where I store all the projects for the remastered sections of this course. 60 00:04:39,520 --> 00:04:44,400 Your projects will probably be on drive C, in a directory called IdeaProjects. 61 00:04:44,400 --> 00:04:47,840 If you've put them somewhere else, then you'll know where to find them. 62 00:04:47,840 --> 00:04:53,360 I've also got a file, called dot DS_Store. Note the different icons that Windows uses 63 00:04:53,360 --> 00:04:59,040 for directories and files. The Mac and Linux file managers also use different icons. 64 00:04:59,040 --> 00:05:03,280 Directories are represented by a folder icon. Files have different icons, 65 00:05:03,280 --> 00:05:06,800 depending on what the file contains. On my screen, 66 00:05:06,800 --> 00:05:11,788 the current-python-masterclass-remaster directory is represented by a yellow folder icon. 67 00:05:11,788 --> 00:05:16,160 The dot DS_Store file is represented by an icon that represents a sheet of paper, 68 00:05:16,160 --> 00:05:21,884 with one corner turned down. That's become a universal icon for a document. 69 00:05:22,560 --> 00:05:25,600 What's the difference between a file and a directory? 70 00:05:25,600 --> 00:05:29,120 All the information you save on your computer is stored in files. 71 00:05:29,120 --> 00:05:34,339 We've created a lot of Python files throughout this course, and each one contained Python code. 72 00:05:34,560 --> 00:05:37,516 So you've already seen that you can store text in files. 73 00:05:37,680 --> 00:05:42,640 Files can also contain images, or music. If you've used a spreadsheet program, 74 00:05:42,640 --> 00:05:47,588 or word processor, your documents are also stored in files. 75 00:05:49,280 --> 00:05:54,399 Files are stored in directories. So a directory is just a container for files. 76 00:05:54,480 --> 00:05:58,640 Think of a directory as the digital equivalent of folders in a filing cabinet. 77 00:05:58,640 --> 00:06:04,080 In fact, directories are also called folders. I'll use both terms, so you get used to the 78 00:06:04,080 --> 00:06:09,520 fact that they mean the same thing. Back in the Windows file manager, 79 00:06:09,520 --> 00:06:14,548 I'll double-click that directory, to open it up and have a look at what it contains. 80 00:06:15,680 --> 00:06:19,680 Inside, I've got folders for each of the Projects for the course. 81 00:06:19,680 --> 00:06:26,480 There's DictAndSet, Functions_Intro, and so on. Folders can contain other folders. They're used 82 00:06:26,480 --> 00:06:31,040 to organise the files on your hard drive, so that you can find things more easily. 83 00:06:31,040 --> 00:06:35,520 They also prevent the files from one application interfering with the files from another. 84 00:06:35,520 --> 00:06:39,360 We can see an example of that. I'll double-click Functions_Intro and we 85 00:06:39,360 --> 00:06:47,035 can see the __pycache__ directory, at the top. That holds the compiled Python code for this project. 86 00:06:47,035 --> 00:06:50,000 Each project will have its own pycache folder. 87 00:06:50,000 --> 00:06:56,320 I'll go back one level, and open the Sequences directory. That also has a pycache folder. 88 00:06:56,320 --> 00:06:58,560 If projects weren't stored in their own folders, 89 00:06:58,560 --> 00:07:04,000 one project might change the compiled files for a different project, and things could get messy. 90 00:07:04,000 --> 00:07:08,640 Directories, or folders, are used to organise the files on the hard drive. 91 00:07:08,640 --> 00:07:13,520 As you'll have noticed, IntelliJ creates a new directory for each new project. 92 00:07:13,520 --> 00:07:17,200 That keeps the files for each project together, which is much tidier than having 93 00:07:17,200 --> 00:07:24,000 hundreds of Python files in the same folder. Ok, that's a quick look at files and directories. 94 00:07:24,000 --> 00:07:27,680 Before we move on, there are a couple of settings you should know about. 95 00:07:27,680 --> 00:07:30,800 The first one is one I definitely recommend you turn on. 96 00:07:30,800 --> 00:07:35,680 Open the View menu in the Windows file explorer, and have a look at the options over on the right. 97 00:07:35,680 --> 00:07:41,360 The one I recommend you tick is File name extensions. For quite a while, 98 00:07:41,360 --> 00:07:45,826 that option was disabled by default. If it's unticked, File Explorer doesn't 99 00:07:45,826 --> 00:07:49,760 show the file extensions for a lot of the file types that it recognises. 100 00:07:49,760 --> 00:07:53,582 That can be confusing, so make sure you tick that box. 101 00:07:54,720 --> 00:07:58,480 Mac OS has a similar option, in the Finder preferences. 102 00:07:58,480 --> 00:08:01,760 Have a look on the Advanced tab, if you want to change it. 103 00:08:01,760 --> 00:08:06,720 Linux doesn't have an equivalent option. File extensions aren't hidden on Linux. 104 00:08:06,720 --> 00:08:10,800 File extensions are used by Windows to identify the file's contents. 105 00:08:10,800 --> 00:08:16,640 For example, a jpeg image will be stored in a file with the extension .jpg or .jpeg. 106 00:08:16,640 --> 00:08:19,680 Text files are usually stored in .txt files. 107 00:08:19,680 --> 00:08:24,432 And we've been using the extension .py for our Python source code files. 108 00:08:25,520 --> 00:08:28,402 The other option you should know about is Hidden items. 109 00:08:28,402 --> 00:08:32,640 I've got that ticked, which means hidden items are showing in the File Explorer. 110 00:08:32,640 --> 00:08:35,760 The default is unticked. Most of the time, 111 00:08:35,760 --> 00:08:41,655 you probably don't want to see hidden files. If you can't see them, you can't accidentally delete them – 112 00:08:41,655 --> 00:08:45,840 that's one reason why they're hidden. They're also of no interest to ordinary users, 113 00:08:45,840 --> 00:08:50,539 so they're hidden to avoid cluttering the display with files that most people aren't interested in. 114 00:08:50,640 --> 00:08:55,212 As programmers, we will sometimes need to view those hidden files and directories. 115 00:08:55,280 --> 00:08:59,158 So now you know how to reveal them – just tick that box. 116 00:09:00,160 --> 00:09:05,200 The Finder in Mac OS, and Linux file managers such as Nautilus, also have options to hide 117 00:09:05,200 --> 00:09:11,760 certain files. On those operating systems, hidden files have names that start with a dot, or period. 118 00:09:11,760 --> 00:09:16,406 Configuration files for programs are often stored in a folder whose name starts with a dot, 119 00:09:16,406 --> 00:09:18,880 and you may need to examine those folders. 120 00:09:18,880 --> 00:09:23,429 If you're using a Mac, you can show hidden files in Finder with Cmd-Shift-Period. 121 00:09:23,429 --> 00:09:27,760 That toggles hidden files on or off, for the current directory you're displaying. 122 00:09:27,760 --> 00:09:32,704 On Linux, Nautilus uses Ctrl-H to show hidden files. 123 00:09:34,400 --> 00:09:38,880 Use your operating system's file manager – Windows Explorer, Mac's Finder, 124 00:09:38,880 --> 00:09:42,960 or Nautilus on Ubuntu – to browse through the directories on your hard drive, 125 00:09:42,960 --> 00:09:48,960 and get a feel for how directories (or folders) can contain files, and other directories. 126 00:09:48,960 --> 00:09:55,157 Don't move or delete anything, just spend a bit of time examining the contents of your hard drive. 127 00:09:56,480 --> 00:09:59,280 You should be able to find your home folder. Its name 128 00:09:59,280 --> 00:10:02,800 will usually be the same as the name you use to log into your computer. 129 00:10:02,800 --> 00:10:06,800 On Windows, it will normally be on Drive C in the Users directory. 130 00:10:06,800 --> 00:10:11,760 But it could be on a different drive, if your computer was set up with additional disk drives. 131 00:10:11,760 --> 00:10:18,080 On a Mac, your home folder is also in Users. On Linux, look for /home. Your home folder 132 00:10:18,080 --> 00:10:20,983 should be in there. Inside your home folder, 133 00:10:20,983 --> 00:10:24,080 you should find the directories where your operating system defaults to storing 134 00:10:24,080 --> 00:10:29,600 your documents, pictures, videos and so on. In the next video, we'll have a quick look 135 00:10:29,600 --> 00:10:38,480 at the command prompt (on Windows) and terminal (on Mac OS and Linux). See you in the next video.