Boston Python Workshop 7/Friday/Tutorial: Difference between revisions

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<b>Step 1: write a function signature</b>
<b>Step 1: write a function signature</b>


A <b>function signature</b> tells you how the function will be called. It starts with the keyword <code>def</code>, which tells Python that you are defining a function. Then comes a space, the name of your function, an open parenthesis, the comma-separated input <b>parameters</b> for your function, a close parenthesis, and a colon. Here's what a function signature looks like for a function that takes no arguments:
A <b>function signature</b> tells you how the function will be called. It starts with the keyword <code>def</code>, which tells Python that you are defining a function. Then comes a space, the name of your function, an open parenthesis, the comma-separated input <b>arguments</b> for your function, a close parenthesis, and a colon. Here's what a function signature looks like for a function that takes no arguments:


<code>def myFunction():</code>
<code>def myFunction():</code>
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<code>def myFunction(myList, myInteger):</code>
<code>def myFunction(myList, myInteger):</code>


Parameters should have names that usefully describe what they are used for in the function.
Arguments should have names that usefully describe what they are used for in the function.

We've used the words <b>parameters</b> and <b>arguments</b> seemingly interchangeably to reference the input to functions. The distinction isn't really important right now, but if you're curious: in function signatures the input is called parameters, and when you are calling the function the input is called arguments.


<b>Step 2: do useful work inside the function</b>
<b>Step 2: do useful work inside the function</b>
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Underneath the function signature you do your useful work. Everything inside the function is indented, just like with if/else blocks, so Python knows that it is a part of the function.
Underneath the function signature you do your useful work. Everything inside the function is indented, just like with if/else blocks, so Python knows that it is a part of the function.


You can use the variables passed into the function as parameters, just like you can use variables once you define them outside of functions.
You can use the variables passed into the function as arguments, just like you can use variables once you define them outside of functions.


<pre>
<pre>
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