Python for Absolute Beginners Transcripts
Chapter: Writing your first lines of code
Lecture: Concept: Variables and types

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0:00 Let's review this idea of variables data values, and types. We saw that we can create variables
0:07 just by saying their name, and then giving them a value. Though, in our Python REPL, Read, Eval, Print, Loop we were able to type x = 42.
0:16 Notice this green dip with a hash in Python you can make comments that are meant for people that have no effect on how code runs.
0:23 So we're going to say hash if we were to run Typhon X but what we'd get back is this class inch. Remember we said there's a way in Python to ask
0:32 What type of data are we working with? And here when you work with whole numbers in Python that's an integer.
0:38 We came up with another variable, 19, also an integer then we saw we can use them in expressions like what is x + 7 * y?
0:48 Then if we don't assign it to a value that just kicks out whatever the response or the evaluation, the value of it is, so 175.
0:55 We can also create text base data and these are strings. They go in single quotes, or double quotes. Like we have here, so we said name = 'Michael'.
1:05 Now if we asked the type again this one has changed from int to str. And you can combine strings and numbers by adding them together
1:14 but if you try to mix these types it doesn't really like it so much. Here we saw that there was an error if we said name + x. We got an exception.
1:22 The program sort of crashed and if it was a real program that we were running it wouldn't continue, it would just stop and say
1:27 Something's broken, we're done. But in the REPL it just prints out the error and carries on. If we didn't want to combine numbers and strings
1:35 we can use a format string. We know we have a format string because it has that little f at the beginning. So here we say, Hi, pearly name.
1:43 And that just takes the value, currently Michael. Looks like you did math, and then we want to restate the equation and then the value.
1:49 So x, {x + 7 * y} is going to be whatever that value is. Now, I could've assigned that response or that evaluation to a variable.
2:01 We could've said something like z = x + 7 * Y and that's probably the best thing to do actually. But I wanted to make the point
2:09 that it's not just variables that can go into these format strings inside those curly braces. More general Python expressions can go in there.
2:17 So, if you wanted to compute something or you wanted to call a function get some behavior out of a piece of data we'll see how to do that later.
2:24 You can do that there. So, these are very very flexible. And we run this code, we get Hey Michael looks like you did math, 42 + 7 * 19 is 175.
2:35 Aright, so here we've created a bunch of variables we've set their data and we've set their data values which implies a data type.
2:42 We saw that we don't say the type in Python but that it is important to know about it. Like for example, name plus X, we should know
2:49 that we can't do those things. We need to do the thing at the bottom. Create that cool little string that we got in the end.

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