1.3. Documenting functions

You can document a Python function by giving it a doc string.

Example 1.4. Defining the `buildConnectionString` function’s `doc string`


def buildConnectionString(params):
    """Build a connection string from a dictionary of parameters.

    Returns string."""

Triple quotes signify a multi-line string. Everything between the start and end quotes is part of a single string, including carriage returns and other quote characters. You can use them anywhere, but you’ll see them most often used when defining a doc string.


	Triple quotes are also an easy way to define a string with both single and double quotes, like `qq/.../` in Perl.

Everything between the triple quotes is the function’s doc string, which documents what the function does. A doc string, if it exists, must be the first thing defined in a function (i.e. the first thing after the colon). You don’t technically have to give your function a doc string, but you always should. I know you’ve heard this in every programming class you’ve ever taken, but Python gives you an added incentive: the doc string is available at runtime as an attribute of the function.


	Many Python IDEs use the `doc string` to provide context-sensitive documentation, so that when you type a function name, its `doc string` appears as a tooltip. This can be incredibly helpful, but it’s only as good as the `doc string`s you write.

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