Effective PyCharm (2021 edition) Transcripts
Chapter: Refactoring
Lecture: Concept: Refactorings

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0:00 Let's do a quick flyover of all the main concepts around re factoring and PyCharm we've
0:04 covered and actually introduce one or two more that we didn't take the time to do
0:08 as a demo. So remember we have the re factoring menu,
0:12 we can get to all sorts of good things.
0:14 I would say extract and introduces probably where you're gonna be most as well as rename
0:18 But there is the more specialized ones like pull members up,
0:21 push members down and so on.
0:23 The way that I typically get to refactoring is using the refactor this the
0:27 first thing in this menu which on Mac OS is ctrl+t.
0:30 So highlight the code or put the cursor on the thing you want to
0:34 rename. Refactor or whatever.
0:36 Press 'ctrl+t' or your OS is hotkey.
0:39 And then after the races, the first thing that we looked at was renaming.
0:44 Remember having a good name is super important and it can help avoid using comments as
0:49 deodorant for code smells. So good name often tells you what's happening in the code
0:53 without the need for comments here.
0:55 Maybe this was just for CN creatures,
0:58 we want to make it more obvious.
0:59 So for creature in creatures, you notice we're renaming in the for loop location and
1:05 it's changing throughout this whole file where the creature or see what's being used before,
1:11 if we wanted to change the way the game played.
1:13 So not just wizard could attack,
1:15 but like a toad could emerge from the forest and surprise attack us.
1:18 We'd want to use the attack functionality built into wizard,
1:22 but make it available to all creatures.
1:23 So we could use pull members up over here to attack,
1:27 say pull members up and say we'd like to push this up to the creatures so
1:30 all creatures have the ability to attack,
1:32 not just wizards, we wanted to reverse that,
1:36 we had some functionality that was in creature,
1:38 but we want a specialised version in each class,
1:40 we can push members down and we can check it off like that and then every
1:45 drive class will get its own copy,
1:46 which we can then specialize. I love the extract variable feature,
1:52 it helps with debugging, it helps with understanding and so on.
1:55 We talked about this, get defensive role,
1:57 we said, you know, this is not great,
1:59 it's not entirely clear what's happening here.
2:02 So we could extract this out as a variable and then we'll let us see it
2:06 in the debugger what we did is broken into multiple variables,
2:09 so we could actually see each little piece but still this will help us in our
2:12 debugging if we decided, you know,
2:15 that's not the way we wanted to go.
2:16 Actually, there's no real reason for this variable here,
2:19 let's just return that expression itself.
2:22 We can do the reverse of extract very but we can in line a variable and
2:25 now we have just this like,
2:27 clean one line feature. Another thing that's really cool is we can extract a constant
2:33 constant in python, it's not a real language way to enforce it,
2:37 but the convention is that they're all caps.
2:40 So if we go over here and we try to extract this 12,
2:44 it's a constant. It's going to put it at the module level and then we
2:47 can give it a name like the dye sides.
2:49 Like how many sides does my dye have this one,
2:51 it's a 12 sided one. This will let us easily change this one.
2:55 Constant that will apply to the rest of the program,
2:57 highlight the 12. We? Refactor and say create extract the constant and go
3:02 over here and then it's going to replace the usage of the 12 wherever we were
3:06 using it with the constant. We also saw that we might want to have some
3:11 kind of constant become configurable. That could be passed into a method.
3:16 Something that's not a variable at the moment,
3:17 but on an argument, what could be?
3:19 So in the for example, we have the seven.
3:21 That was our modifier. We can go over here and do an extract parameter.
3:25 It will create a modifier parameter,
3:27 give it the default value. So by default it behaves the same.
3:30 But now it's configurable. This is really handy way to add more extensive bility and
3:36 more flexibility to your code. Here's one that we did not cover if we're going
3:41 to create a python package, there's a certain structure that it has to have.
3:46 There's a directory name. That's the name of the package And in there there's a
3:50 '__init.py' file and potentially others what we've been working with so far
3:55 is just a couple of files that run together and they're technically known as modules.
3:59 So notice we have this actors.py,
4:02 we can re factor, convert to a python package,
4:05 watch what's going to happen here,
4:07 This actors right there and all the code in it is going to get changed.
4:11 Actors are going to become a directory.
4:14 There's going to be a file called __init.py.
4:17 And the implementation that was in that module is now moved to the __init.py
4:22 By default, we've got this new structure,
4:25 which it's not usually required, but if you're working with packages and you need to
4:30 install things or especially if you want to ship this over two PyPI or
4:33 share it with other programs, having it as a package might be exactly what you need. It's the quick way to do inPyCharm.