5.2 Using the map() function to apply a function to a collection
A scalar function maps values from a domain to a range. When we look at the math.sqrt() function, as an example, we’re looking at a mapping from a float value, x, to another float value, y = sqrt(x), such that y2 = x. The domain is limited to non-negative values for the math module. When using the cmath module, any number can be used, and the results can be complex numbers.
The map() function expresses a similar concept; it maps values from one collection to create another collection. It assures that the given function is used to map each individual item from the domain collection to the range collection—this is the ideal way to apply a built-in function to a collection of data.
Our first example involves parsing a block of text to get a sequence of numbers. Let’s say we have the following chunk of text:
>>> text= """\
... 2 3 5 7 11 13 17 19 23 29
....
