Subsection 1.1.1: Example 1 - Using Length Method

One prominent illustration of duck typing is utilizing sequences like lists, tuples, and strings. Though these are distinct types, the len() function can be applied to all because they share a common behavior: the implementation of the length method, which counts the elements in a sequence. For instance:

def print_length(sequence):

print("Length:", len(sequence))

# Works for list

print_length([1, 2, 3]) # Output: Length: 3

# Works for tuple

print_length((1, 2, 3)) # Output: Length: 3

# Works for string

print_length("Hello") # Output: Length: 5

Here, although we designed our function to accept any form of "sequence," we never explicitly defined the types of objects that could be passed in. Instead, we relied on their shared behavior, enhancing flexibility and readability in our code.

Subsection 1.1.2: Example 2 - Creating Iterable Objects

Another excellent case of duck typing involves iterable objects. An iterable is any object that includes an __iter__() method, enabling iteration through its contents using a for-loop. Let’s create a custom iterable object named CountUpTo:

class CountUpTo:

def __init__(self, max_count=10):

self._current = 0

self.max_count = max_count

def __iter__(self):

return self

def __next__(self):

if self._current >= self.max_count:

raise StopIteration

current = self._current

self._current += 1

return current

for i in CountUpTo():

print(i)

# Output:

# 0

# 1

# ...

# 9

In this example, we did not inherit from any built-in classes like list, tuple, or str. However, by implementing the necessary methods (__iter__() and __next__()), our custom object can be treated as any other iterable in Python.