Python for Beginners, Part 4: Interactive Shell vs. Script

We will discuss the difference between an interactive python terminal vs. A python script. In case you missed it, here are the previous parts of the series:

• Python for Beginners, Part 1: How to Download and Install Python
• Python for Beginners, Part 2: Hello World Exercise
• Python for Beginners, Part 3: The Turtle Module

Transcript

00:00 - Okay, in this video,00:01I'm gonna go over the solution to the previous problem00:03 that I posed to you, and also,00:05 we're gonna learn how to write the turtle,00:07 the entire thing,00:09 in one go.00:11 So, the problem that I posed to you is,00:14 make a square with the turtle.00:16 Well, in your case,00:17 let's see how you could do exactly that.00:21 So, let me find the file where we opened up the turtle.00:23 Let me close that guy right there.00:25 Copy this line and paste it right there.00:29 Okay, my turtle has begun.00:31 Well, the idea is simple.00:34 I take this line forward, and go 100.00:38 Now, since sometimes programmers are lazy,00:40 I don't want to keep writing this over and over again,00:42 so one thing I can do to make my life easier00:45 is go to the line that I want to click on,00:48 I want to use, basically.00:50 Go to that line, click my mouse there,00:52 hit 'enter', it brings that down at the bottom,00:55 as you can see right here.00:56 And now I can just hit 'enter'.00:59 So, you can see my turtle just moved left, okay?01:02 Now it's facing up.01:05 Now what I want to do is move it forward again,01:08 and you can see that it's facing up again,01:11 er, I'm sorry, it's ...01:13 It moved up, now I need to make it face left.01:16 So, how do I do that?01:17 I go left, make it turn 90 degrees,01:19 and you can see it turned 90 degrees.01:22 Now I want it to move 100 again.01:25 You can see it move forward.01:27 And 90 degrees, and then 100 once again,01:31 and I have made the square.01:34 Now, what I want you to be able to do is,01:38 make a Python file, which means that,01:41 remember this thing that we opened up right here,01:45 where we write all of the code at once?01:48 So, for example,01:50 I'm gonna close it,01:51 I'm gonna show you how to open it again, okay?01:53 So, I'm gonna close this one,01:54 and I will simply open it again.01:56 'New file', or 'Command-N'.01:59 And I will go and put it to the right side,02:02 just so I have these side by side,02:05 and I will say something like 'import turtle'.02:08 Remember that command.02:09 If you don't use that command02:11and you try to do 'turtle',02:12 your program will be like,02:14 "What the heck is 'turtle'?"02:16 So, by doing 'import turtle',02:18 now it knows what 'turtle' is.02:20 It's like when you're talking about your friends,02:24 if you talk about your friend John, right?02:27 Like, let's say you're talking about your friend John02:29 to your mom, or to your dad,02:32 and you're like,02:33 "Dad, this guy blah blah blah",02:35 you're dad's gonna be like,02:36 "Who the heck is John?"02:37 So, you're gonna be like,02:38 "Oh, yeah, you remember John from my fifth grade class?"02:43 And then your dad, if you're talking to him,02:44 he's gonna say,02:45 "Oh, okay, I know who you're talking about".02:47 So, 'import' is basically like,02:50 hey, Python,02:51 import that turtle that those coders wrote,02:54 and now we can use it,02:55 and Python is like,02:56 "Oh, that turtle",02:58 but if you don't have this 'import' command here,03:01Python's gonna be like,03:02 "What the heck?03:03 "What turtle are you talking about?03:04 "You must be out of your mind."03:06 Anyways.03:07 We're gonna import this turtle.03:09 Alright, so now here's what I want you to do.03:11 I want you to write a script that makes the turtle03:14 in one single go, okay?03:18 And I want you to make that square with the turtle03:21 straight up in one go.03:22 For example,03:23 let's come over here to our script that I've written,03:26 and if I write stuff here,03:28 it does things immediately, right?03:30 As you saw,03:30 but if I come to my right side over here ...03:34 Oh, by the way, just one quick note.03:36 Whatever you do, do not name this file 'turtle.py'.03:40 You can name it 'turtle_game', or 'game',03:44 or something else,03:45 just don't name it turtle,03:47 because then it confuses this turtle here03:49 with this file,03:50 and everything goes all over the place.03:53 So, don't do that,03:54 'cause I ended up doing that and it caused lots of problems.03:58 Alright, so let me just show you what happens04:00 when I run this file.04:02 I'll go to 'Run', I'll hit 'Run module',04:04 and hit 'OK'.04:06 And you can see that my turtle went04:08 and did all those things in one go.04:10 How cool is that?04:11 So you don't have to sit there, type it all in.04:13 You can just write it in one go,04:14 and it'll do that every single time.04:17 So, I want you to work on that square,04:19 but before you go and do that,04:21I just want to show you what this file actually looks like.04:24 So, if I go to,04:29 let's say,04:30 'Documents', and 'Clever Programmer',04:33 'Practice Exercises',04:35 and we take a look at this file, 'turtle_game',04:38 it's just a text file with this code in here, okay?04:42 That's really it, that's all that's going on in here.04:45 So, I'm gonna04:47 leave it here.04:50 The code that you write for the square,04:52 I want you to either go to the Youtube place,04:55 Youtube channel, and post it in the comments,04:58 or I want you to paste your code right here in the comments05:01on cleverprogrammer.com, okay?05:03 I'm gonna take a look at it.05:05 I will see you in the next video.