13.5. Defining a function as a parameter
In Section 11.6 we have seen an example of
a function that can take another function as a parameter. This
is a general mechanism in Python. Another example is
the sort() function. This function can
take a comparison function as a parameter.
def numeric_compare(x, y):
if x>y:
return 1
elif x==y:
return 0
else: # x<y
return -1
>>> a = [5, 1, 10, 2]
>>> a.sort(numeric_compare)
>>> print a
[1, 2, 5, 10]
 | Exercise 13.1. Sorting a dictionary by its values |
|
Let's say that we have a dictionary of the words occurring in
a file associated with their number of occurrences. How would
you print this dictionary by descending occurrences? You have
to define a function freq_compare which
takes as its two parameters the key of the entries that you
want to compare.
|
