Editing Intro to Programming and Data Science (Fall 2024)/Day 1 Tutorial (section)

==Types==

[[File:Geometry.png|150px]]

There's a helpful '''function''' (more on what a function is in a second) called <code>type</code> that tells you what kind of thing -- what '''data type''' -- Python thinks something is. We can check for ourselves that Python considers '1' and '1.0' to be different data types:
<syntaxhighlight lang="python">
 type(1)</syntaxhighlight>
<syntaxhighlight lang="python">

 type(1.0)
</syntaxhighlight>
So now we've seen two data types: '''integers''' and '''floats'''. Python tags your variables with a data type to make better guesses about what you want and to prevent errors. Another data type you'll run into is strings (a sequence of letters, numbers, and symbols, like the ones you're reading right now -- we'll look at strings a bit more in a moment).

What's a "function"? Here are the important ideas about functions:

* A function encapsulates (packages up) a useful bit of work and gives that work a name.
* You provide input to a function and it produces output. For example, the <code>type</code> function takes data as an input, and produces what type of data the data is (e.g. an integer or a float) as output.
* To use a function, write the name of the function, followed by an open parenthesis, then what the function needs as input (we call that input the '''arguments''' to the function), and then a close parenthesis.
* Programmers have a lot of slang around functions. They'll say that functions "take" arguments, or that they "give" or "pass" arguments to a function. "call" and "invoke" are both synonyms for using a function.

In the example above, "type" was the name of the function. <code>type</code> takes one argument; we first gave <code>type</code> an argument of 1 and then gave it an argument of 1.0.

==== Diagram of "calling" a function ====

[[File:Function_diagram.png]]

===Jupyter history===

In your Jupyter notebook, any time you want to re-run a command, you can select that cell again and repeat the same Shift+Enter action to re-run the cell.