https:/.../fb58d0e3-0e42-41ee-b5a6-ad75015afcbf-2bbdb9c5-cb09-436f-9ff5-ad8c0120ab50.mp4?invocationId=1a5223d2-6e03-ec11-a9e9-0a1a827ad0ec

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Well, in this video, I'm going to talk with you about some of the basic control structures that we have

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in Python and the syntax that Python uses for indicating different pieces of code.

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The learning outcomes for this video are for you to be able to write basic python control structures.

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Understand the python block syntax. No, the standard practice for using whitespace in Python.

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One of the key concepts here is that Python uses whitespace to detect blocks such as the bodies of loops or conditionals.

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Unlike other languages such as Java, JavaScript, HPC, etc., all use squiggly braces.

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Python uses indentation as syntactically significant indicator of what a block is, such as the body of a loop.

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So in the first Python intro video, we saw a for loop in the for loop iterates over it iterable.

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So you the, the, the syntax is that we have for ie the variable name in.

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Range of music range here, but this is the iterable expression.

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That's something that we can we can loop over and then within within that loop, we are going to we're gonna print and we're using an F string.

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Remember the F string that says use variables in the string.

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And so we are we're printing out the iteration number through each iteration of this loop.

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And then at the end of the loop, we're gonna print done, and that's gonna happen once.

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Because whitespace still limits blocks.

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The colon and the and the indentation, they indicate that we're in a new block.

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And then when the indentation stops and it goes back out to the same level.

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As the for loop started, that indicates the end of the block.

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So, as I said, the python block begins with a colon at the end of the line.

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And there's several different python keywords that. Are something that can start a block the if family f.

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Else L.F., the loop's foreign while and then the keywords for defining functions and classes, def and class block contents indented one level.

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The standard practice here is to use force bases.

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Jupiter, along with most modern python editing environments, default their configuration to force spaces for you automatically.

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But this convention, while Python does not strictly mandate this.

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All it mandates is that you are consistent. You can't say mixed tabs and spaces in the same file.

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This almost universally standard python practice is to indent with four spaces

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and then the block ends when the indentation returns to the previous level.

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You can also have comments in Python, a comment begins with a hash and continues until the end of the line.

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You can have a car line where all it is is a comment. You can also put a comment at the end of a line that contains some code.

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When we're writing Jupiter notebooks,

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we're going to put a lot of the discussion and the explanation in markdown cells in the Jupiter notebook rather than in comments.

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But comments are very useful when you're when you start writing Python scripts.

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They're also useful when you want when you want to write.

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Just really briefly, why a particular line in one of your code cells is working the way that it's working?

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The if statement is structure.

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It works like the fourth statement in terms of how the blocks work.

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And we open with if we don't need any parentheses, we have F and we have an expression in this case,

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we're gonna say if X is greater than or equal to 10, then we're one to print big if Elif is the python else.

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If you can have as many of these as you want and if you don't have to have one, you don't have to have an else either.

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But it's not else F or else, if it's just L.F. e-Life is the python syntax for else F.

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So if it's not greater than 10 but it is greater than or equal to five, it's going to print medium.

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And that's the one we're actually going to run in this case because X is equal to five.

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And then finally. Else we're going to print small. So in Python there are several things that are considered false.

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For the purpose. Most for the purposes of. Of an if statement.

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The bout valued the boolean value false, which you write with an uppercase F, is considered false as is none, which is a special python value.

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That is the python's version of a no means no data here.

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Zero is false. Empty containers, empty lists, sets, tuples and empty strings are all also false.

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Most other things are true. But those are the.

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Those are the. That's how ifs work in Python. They aren't strict like in Java.

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It has to be a boolean python does not require it to be a billion.

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It requires to be something that can be converted to a boolean. And then these are the things that.

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These are the things that Python converts to false when it's doing that boolean conversion a while loop iterates until a condition becomes false.

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I'd put a past statement here. The past is not part of the while loop. The past is just here to make the syntactically valid python.

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Because while loops can't be empty in general, Bloks cannot be empty.

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So passe is a python statement that does nothing.

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It's just needed when you need to make something syntactically valid. Maybe you're in the middle of testing some code.

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Maybe you're working on an F and you don't have all that figured out yet. So you just want to make one of the branches of the F.

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Do nothing. For now, you can just say pass. So to wrap up, Python provides the usual control control structures for a programing language.

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If for while blocks crucially are based on indentation and the standard there is to use for spaces.

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The hash sign starts a comment. There is some limitations to working with for loops.

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We're not going to use for work to working with, well, any loops in Python.