1 00:00:00,480 --> 00:00:05,480 Up until now we've been using Repl.it as our code editor and Repl.it has a 2 00:00:06,330 --> 00:00:11,330 number of great features like how easy it is to share code and to fork copies of 3 00:00:12,720 --> 00:00:17,370 the same code so that you can always get the starting code and the final code. 4 00:00:18,120 --> 00:00:21,090 But Repl.it does have its limitations. 5 00:00:21,600 --> 00:00:26,600 And as you're becoming more and more advanced and you start building more 6 00:00:26,610 --> 00:00:31,380 complex projects, you'll start to feel the constraints of a simple text editor 7 00:00:31,410 --> 00:00:36,390 like Repl.it. Now PyCharm is a tool that's used by professionals. 8 00:00:36,900 --> 00:00:41,280 And I want to show you a couple of features so that you can see firsthand why 9 00:00:41,280 --> 00:00:44,340 PyCharm is so popular with Python developers. 10 00:00:44,640 --> 00:00:48,450 And the first thing I really like about it is also a very, very basic thing, 11 00:00:48,840 --> 00:00:53,040 it's spellcheck for the English words that you use in your code. 12 00:00:53,610 --> 00:00:55,710 This just means that while you're writing code, 13 00:00:55,710 --> 00:00:59,970 you are creating names for your variables, creating your keys, your values, 14 00:01:00,450 --> 00:01:05,160 or your print statements, that it makes sure that the English that you write, 15 00:01:05,160 --> 00:01:09,060 the parts that's not actually code, is actually spell-checked 16 00:01:09,240 --> 00:01:12,330 and you won't believe how many times this will save your skin. 17 00:01:13,050 --> 00:01:15,840 Here's an example, something that's really, 18 00:01:15,840 --> 00:01:19,380 really sensitive to spelling is a dictionary. 19 00:01:19,770 --> 00:01:24,770 We all know that when we're using a dictionary and let's say we wanted to print 20 00:01:26,100 --> 00:01:31,100 one of the values from our dictionary. We're taking our contacts and getting hold 21 00:01:31,860 --> 00:01:36,720 of James's details, and then we're trying to get hold of his phone number. 22 00:01:37,170 --> 00:01:40,230 Now, if you type this wrong, for example, 23 00:01:40,230 --> 00:01:44,910 if I wrote phone number without an 'e', and I try to run this, 24 00:01:45,090 --> 00:01:47,100 then you'll see, I get an error. 25 00:01:47,610 --> 00:01:52,050 But the spell check should already alert you to the issue before you even hit 26 00:01:52,050 --> 00:01:55,590 run. See how this is underlined with a squiggle 27 00:01:55,890 --> 00:01:58,890 and it tells you that there's a typo in the word phon, 28 00:01:59,310 --> 00:02:02,610 and you can click change to phone maybe. 29 00:02:03,360 --> 00:02:06,300 And it's just a subtle hint to say, 'Hey, 30 00:02:06,570 --> 00:02:10,800 I think maybe you got that wrong. Just DoubleCheck.' And indeed, 31 00:02:10,830 --> 00:02:11,970 once we fix that, 32 00:02:12,270 --> 00:02:16,290 then we get rid of all our issues and everything works perfectly. 33 00:02:17,070 --> 00:02:22,070 The next feature that I really like is having more space to develop. 34 00:02:23,370 --> 00:02:25,140 What do I mean by this? Well, 35 00:02:25,200 --> 00:02:29,940 very often we actually tend to have more than one code file, right? 36 00:02:30,210 --> 00:02:30,840 For example, 37 00:02:30,840 --> 00:02:35,840 let's say that we moved our contacts into this data file and we imported it 38 00:02:37,200 --> 00:02:38,033 instead. 39 00:02:38,460 --> 00:02:42,870 So it will say from data import contacts. 40 00:02:43,590 --> 00:02:48,590 And now when I want to code things up and I want to get hold of certain things, 41 00:02:49,350 --> 00:02:51,840 for example I want to get Jenny's email, 42 00:02:53,190 --> 00:02:57,300 then ideally I would want to see this side by side, 43 00:02:57,300 --> 00:02:59,500 right? In PyCharm 44 00:02:59,710 --> 00:03:03,190 all you have to do to split the screen is just right 45 00:03:03,190 --> 00:03:06,640 click on the file and then say split and move right. 46 00:03:07,390 --> 00:03:10,990 And now all of a sudden you can see both sides at once. 47 00:03:11,230 --> 00:03:16,120 This means it so much easier to refer to some other piece of code when you're 48 00:03:16,120 --> 00:03:16,953 developing. 49 00:03:17,020 --> 00:03:22,020 So here I can now easily see that the key for Jenny has a capital J, 50 00:03:22,540 --> 00:03:24,430 so I have to tap into my contacts, 51 00:03:24,730 --> 00:03:28,600 tap into the key Jenny and then get hold of her email. 52 00:03:29,020 --> 00:03:34,020 This split-screen comes in really handy as your code gets more complex and 53 00:03:34,330 --> 00:03:35,890 there's more and more files. 54 00:03:37,240 --> 00:03:42,240 And now another advanced feature of an IDE compared to a simple text editor like 55 00:03:43,300 --> 00:03:46,630 Repl.it is a built-in linter. 56 00:03:47,020 --> 00:03:52,020 So what is a linter? Well, a linter in real life, is something that picks off a 57 00:03:52,510 --> 00:03:53,470 little bits of dust, 58 00:03:53,470 --> 00:03:58,470 bits of lint from your clothing, and in Programming it's something that picks out 59 00:04:00,370 --> 00:04:05,370 bits of code that you've written that might not be in accordance to the style 60 00:04:05,770 --> 00:04:10,540 guide. When we're writing code and we're trying to decide, well, 61 00:04:10,570 --> 00:04:15,430 how many spaces do I leave between things, do I use tabs or spaces, 62 00:04:15,790 --> 00:04:17,680 what is the maximum line length, 63 00:04:18,010 --> 00:04:22,720 all of these sort of things that maybe won't break your program per se, 64 00:04:23,140 --> 00:04:27,550 but it will mean that your program might look different from somebody else's 65 00:04:27,880 --> 00:04:31,630 and you just want to know what is the convention so that you can keep your code 66 00:04:31,630 --> 00:04:34,480 consistent with other Python developers. Well, 67 00:04:34,480 --> 00:04:36,760 this is what a style guide is for. 68 00:04:37,030 --> 00:04:41,650 And the style guide that most Python developers will abide by is something 69 00:04:41,650 --> 00:04:43,000 called PEP 8. 70 00:04:43,600 --> 00:04:47,560 And we've already seen this when we were talking about tabs versus spaces. 71 00:04:47,860 --> 00:04:48,460 For example, 72 00:04:48,460 --> 00:04:53,460 the guidance is that an indentation should have four spaces, and indeed it should 73 00:04:55,360 --> 00:04:57,970 be spaces over tabs. 74 00:04:58,540 --> 00:05:02,020 And then there are other things like what's the maximum line length 75 00:05:02,050 --> 00:05:04,630 so that your lines of code don't become really, 76 00:05:04,630 --> 00:05:09,630 really long and difficult to read, or things like how many blank lines should 77 00:05:09,970 --> 00:05:14,970 there between functions and variables in your code and all sorts of things. 78 00:05:15,340 --> 00:05:20,340 This is a very long document and it's actually very difficult to read all of it 79 00:05:21,160 --> 00:05:24,040 and remember all of it while you're in the middle of coding. 80 00:05:24,550 --> 00:05:28,030 But luckily for us, if we're using PyCharm, 81 00:05:28,300 --> 00:05:33,070 it automatically applies those rules and guidance to our code 82 00:05:33,430 --> 00:05:36,130 and lints our code. For example, 83 00:05:36,130 --> 00:05:39,250 if I was to create a function called my_function, 84 00:05:40,030 --> 00:05:41,290 and inside here 85 00:05:41,320 --> 00:05:45,280 I've just got two inputs, n1 and n2, 86 00:05:45,820 --> 00:05:50,560 and then it calculates the total by adding n1 to n2, 87 00:05:51,220 --> 00:05:55,210 and it returns the total as an output. Now, 88 00:05:55,420 --> 00:05:59,870 at a later point, I decide to call my function, passing in some numbers, 89 00:05:59,900 --> 00:06:03,470 maybe say 4 and 5. Now firstly, 90 00:06:03,500 --> 00:06:08,500 notice how I've got some light yellow squiggly lines under both of these lines. 91 00:06:09,200 --> 00:06:12,320 And when I hover over it, so I don't have to click on it. 92 00:06:12,350 --> 00:06:16,400 I just keep my cursor on top of the line which has the squiggles, 93 00:06:16,820 --> 00:06:17,390 you can see 94 00:06:17,390 --> 00:06:22,390 it tells me that PEP 8 guidance specifies that there should be two blank lines 95 00:06:23,210 --> 00:06:25,550 after a class or function definition, 96 00:06:25,970 --> 00:06:28,370 but instead it only found one. 97 00:06:28,880 --> 00:06:32,510 So basically what it's trying to say is that the style guide says that there 98 00:06:32,510 --> 00:06:37,510 should be two lines after and before each of your functions so that everything 99 00:06:38,450 --> 00:06:43,430 is more spaced out and easier to read. And here, when I hover over it, 100 00:06:43,760 --> 00:06:47,150 you can see it says there's missing white space after the comma. 101 00:06:47,570 --> 00:06:50,960 So the style guide says that every time you use a comma in your code, 102 00:06:51,290 --> 00:06:54,920 you should always have a space. This way again 103 00:06:54,920 --> 00:06:59,000 it's easier to read and it keeps your code consistent with other Python 104 00:06:59,000 --> 00:07:01,460 developers so that when people look at your code, 105 00:07:01,610 --> 00:07:04,700 they can see that you're following the standard conventions. 106 00:07:05,210 --> 00:07:09,260 But remember that this does not affect how your code runs. 107 00:07:09,650 --> 00:07:13,610 Even with all of these suggestions and these style guide rule breaks, 108 00:07:13,940 --> 00:07:17,420 it doesn't actually mean my code won't work. If I run it, 109 00:07:17,540 --> 00:07:21,350 you can see that it works perfectly without any errors. 110 00:07:21,770 --> 00:07:26,770 And it's only a matter of keeping your code tidy and keeping it in line with the 111 00:07:27,260 --> 00:07:30,890 conventions that Python developers have set out. Now, 112 00:07:30,920 --> 00:07:35,920 another advanced feature of an IDE compared to a text editor is the ability to 113 00:07:36,650 --> 00:07:38,270 view your local history. 114 00:07:39,080 --> 00:07:42,980 What that means is I can go to show history 115 00:07:43,550 --> 00:07:47,030 and just as if you were in a browser, you can see your browsing history, 116 00:07:47,360 --> 00:07:50,450 well here you can see all of your coding history. 117 00:07:50,810 --> 00:07:55,640 So you can scroll back all the way in the last 12 hours and see the edits that 118 00:07:55,640 --> 00:08:00,230 you've made. For example, at thirteen past four today, 119 00:08:00,650 --> 00:08:05,030 I created this brand new function. So this is the current file 120 00:08:05,090 --> 00:08:08,150 and this is what it looked like at that moment in time. 121 00:08:08,810 --> 00:08:11,390 Now scrolling forward into the future, 122 00:08:11,600 --> 00:08:16,600 the next thing I did was I added a new function call here and I added some space 123 00:08:17,540 --> 00:08:18,373 here. 124 00:08:18,500 --> 00:08:23,000 So if you've had some sort of catastrophic events and you realize that you've 125 00:08:23,000 --> 00:08:25,070 really messed up, you've deleted everything, 126 00:08:25,370 --> 00:08:29,810 you can always scroll back to previous time points and simply just copy and 127 00:08:29,810 --> 00:08:30,643 paste the code. 128 00:08:30,920 --> 00:08:35,059 Or you can revert back to that particular time point. 129 00:08:35,690 --> 00:08:40,340 Can you imagine if you are writing your essay and the number of times I have 130 00:08:40,340 --> 00:08:43,309 lost my essay because my computer is crashed. 131 00:08:43,760 --> 00:08:48,500 Imagine if you had this ability to just scroll back in time and find one 132 00:08:48,500 --> 00:08:52,910 snapshot that you liked and then revert everything back to that moment in time, 133 00:08:53,450 --> 00:08:55,830 how powerful could that be? Well, 134 00:08:55,860 --> 00:08:59,820 you now have that in your hands with local history in PyCharm. 135 00:09:00,480 --> 00:09:05,130 Now another really handy feature is the ability to view the structure of your 136 00:09:05,130 --> 00:09:08,610 code. Instead of going to the project navigation, 137 00:09:08,640 --> 00:09:11,130 if I click on this structure pane here 138 00:09:11,580 --> 00:09:16,580 you can see that it breaks down my code into all of the variables and all of the 139 00:09:16,860 --> 00:09:21,180 functions. That means that my function could be declared, you know, 140 00:09:21,210 --> 00:09:24,270 many hundreds of lines somewhere else, 141 00:09:24,630 --> 00:09:28,080 and I'm scrolling around and I'm trying to find it. 142 00:09:28,410 --> 00:09:32,490 All I have to do is look at well, here's my function, 143 00:09:32,730 --> 00:09:33,690 and if I click on it 144 00:09:33,930 --> 00:09:37,860 it takes me straight there and I can now edit it if I wish. 145 00:09:38,130 --> 00:09:41,040 And if I needed the variable jenny_email, well 146 00:09:41,040 --> 00:09:42,630 it takes me straight there as well. 147 00:09:42,750 --> 00:09:46,650 Once you start having lots and lots of variables and lots of lots of functions, 148 00:09:47,010 --> 00:09:48,570 this is a lifesaver. 149 00:09:49,320 --> 00:09:53,280 Now there's a lot of other features that I'm going to show you that PyCharm 150 00:09:53,290 --> 00:09:56,250 can do, but I want to do it gradually. For now 151 00:09:56,310 --> 00:09:58,380 here's the last tip on PyCharm. 152 00:09:58,980 --> 00:10:03,980 Whenever you create a variable or a function name and you end up using it in 153 00:10:04,740 --> 00:10:06,900 lots of places, so for example 154 00:10:06,900 --> 00:10:11,340 you might call my_function here and then you might call my_function again 155 00:10:11,340 --> 00:10:15,270 passing in some different parameters at some later point in time. 156 00:10:15,810 --> 00:10:17,700 And then you decide that actually, 157 00:10:18,120 --> 00:10:21,000 I really don't like the way that I've named that function. 158 00:10:21,420 --> 00:10:26,420 It would make so much more sense if it was called add instead because it returns 159 00:10:26,970 --> 00:10:31,500 the total right? If I was to do this manually in a code editor, 160 00:10:31,500 --> 00:10:32,880 I would have to go add, 161 00:10:33,150 --> 00:10:37,530 and then all of these lines will break and I have to find all of them and then 162 00:10:37,530 --> 00:10:40,050 change them manually. And that's very painful. 163 00:10:40,590 --> 00:10:43,890 So instead, what you can do in PyCharm is you can 164 00:10:43,980 --> 00:10:48,980 right-click on the name of your function or your variable, go to refactor -> rename. 165 00:10:50,790 --> 00:10:55,590 And now it will find all of the places where this function is created, 166 00:10:55,620 --> 00:10:59,100 where it's called, and you can now change it everywhere. 167 00:10:59,490 --> 00:11:01,080 So click refactor, 168 00:11:01,560 --> 00:11:06,560 and it's now found the function that needs to be renamed and also all the places 169 00:11:07,440 --> 00:11:10,770 where it's used. So it's used in two places, here 170 00:11:10,770 --> 00:11:13,140 on line 11 and here on line 14. 171 00:11:13,560 --> 00:11:18,560 So now I click do refactor and what'll happen is it'll change all the places where 172 00:11:20,250 --> 00:11:22,590 it occurs. And it's much, 173 00:11:22,590 --> 00:11:26,160 much safer than say just using find and replace. 174 00:11:26,520 --> 00:11:30,420 Let's say that I had a print statement here that said, um, 175 00:11:30,450 --> 00:11:33,090 my_function is a function. 176 00:11:33,990 --> 00:11:37,110 And if I used find and replace where I just say, well, 177 00:11:37,110 --> 00:11:42,110 my_function now equals add and I click on replace all, 178 00:11:42,420 --> 00:11:47,160 it's going to now change it in all the places. But on the other hand, 179 00:11:47,160 --> 00:11:49,020 if I use refactor -> rename, 180 00:11:49,590 --> 00:11:54,590 then it's going to be intelligent enough to know that this print statement is 181 00:11:55,000 --> 00:11:55,470 just 182 00:11:55,470 --> 00:11:57,630 text whereas the places 183 00:11:57,630 --> 00:12:02,630 where my function is used and the places where my function is declared, 184 00:12:02,880 --> 00:12:05,640 that is what I want to refactor and rename. 185 00:12:05,820 --> 00:12:09,090 And it leaves all of the innocent bystanders alone. 186 00:12:10,080 --> 00:12:15,080 There's a lot of really exciting things yet to come as we start getting used to 187 00:12:15,120 --> 00:12:18,540 using PyCharm. But as with any new tool, 188 00:12:18,840 --> 00:12:22,530 you'll spend a little bit of time getting up and running with it and getting 189 00:12:22,530 --> 00:12:26,190 used to using it. Now, when I was in primary school, 190 00:12:26,520 --> 00:12:31,520 I still remember the moment when I got to graduate from writing with pencils 191 00:12:32,220 --> 00:12:35,640 to writing with a Berol handwriting pen. 192 00:12:36,150 --> 00:12:41,150 And it was a really significant moment in my life when I was allowed to write 193 00:12:41,250 --> 00:12:46,230 with the adult tools. So this is kind of what's happening right here. 194 00:12:46,560 --> 00:12:48,270 We're graduating to PyCharm. 195 00:12:48,510 --> 00:12:52,320 It's going to take a little bit of getting used to and learning our ropes, 196 00:12:52,620 --> 00:12:55,170 but it's going to take us closer to our goals. 197 00:12:55,710 --> 00:13:00,300 Hopefully by now, PyCharm should have now downloaded and you're ready to head 198 00:13:00,300 --> 00:13:03,450 over to the next lesson where we're going to install it.