Practical Programming, 2nd Edition

Functions That Python Provides

Python comes with many built-in functions that perform common operations. One example is abs, which produces the absolute value of a number:

>>> abs(-9)
9
>>> abs(3.3)
3.3

Each of these statements is a function call.

Keep Your Shell Open

As a reminder, we recommend that you have IDLE open (or another Python editor) and that you try all the code under discussion: this is a good way to cement your learning.

The general form of a function call is as follows:

function_name(arguments)

An argument is an expression that appears between the parentheses of a function call. In abs(-9), the argument is -9.

Here, we calculate the difference between a day temperature and a night temperature, as might ...