# 4.9 Default Parameter Values¶

- You can specify that a parameter has a default parameter value.
- When calling the function, if you omit the argument for a parameter with a default parameter value, the default value for that parameter is automatically passed.

In [1]:

    def rectangle_area(length=2, width=3):
        """Return a rectangle's area."""
        return length * width

- Specify a default parameter value by following a parameter’s name with an `=` and a value.
- Any parameters with default parameter values must appear in the parameter list to the right of parameters that do not have defaults.

In [2]:

    rectangle_area()

Out[2]:

    6

In [3]:

    rectangle_area(10)

Out[3]:

    30

In [4]:

    rectangle_area(10, 5)

Out[4]:

    50

In [ ]:

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