For Each w/ Index

# Lists in Python are frequently used, one task that's frequently needed
# is to iterate over a list and retrieve the index of each item in the list
# in Python, this may not as straight-forward as you would be used to in
# some other languages.  We're going to use the sample list below to
# demonstrate a few ways of accomplishing this.
animals = ["Dog", "Cat", "Bird", "Fish"]

# The idiomatic way to do this in Python is with the enumerate function
# https://docs.python.org/3/library/functions.html#enumerate
print("For Each w/ enumerate():")
for index, item in enumerate(animals):
  print("Index : " + str(index) + "\nAnimal: " + item + "\n")

# Example Output:
# For Each w/ enumerate():
# Index : 0
# Animal: Dog
#
# Index : 1
# Animal: Cat
#
# Index : 2
# Animal: Bird
#
# Index : 3
# Animal: Fish

# Often, people seeking a more direct analog to what they're used to, might end up with
# something closer to the following using the range and len functions.  Many people come across
# this solution from Google.
# ex: http://hplgit.github.io/primer.html/doc/pub/looplist/._looplist-solarized003.html
print("For Each w/ range(len()):")
for index in range(len(animals)):
  print("Index : " + str(index) + "\nAnimal: " + animals[index] + "\n")

# Example Output:
# For each, w/ range(len()):
# Index : 0
# Animal: Dog
#
# Index : 1
# Animal: Cat
#
# Index : 2
# Animal: Bird
#
# Index : 3
# Animal: Fish


# As well, the more direct port of a for loop in a language that doesn't have proper
# enumerables is even demonstrated in the documentation for the enumerate function
print("For each, w/ manual indexing:")
index = 0
for animal in animals:
  print("Index : " + str(index) + "\nAnimal: " + animal + "\n")
  index += 1

# Example Output:
# For each, w/ manual indexing:
# Index : 0
# Animal: Dog
#
# Index : 1
# Animal: Cat
#
# Index : 2
# Animal: Bird
#
# Index : 3
# Animal: Fish

# Note that enumerate returns each item as a tuple.  You can see this in action by creating a list
# out of the returned items.
new_list = list(enumerate(animals))
print(str(new_list)) # => [(0, 'Dog'), (1, 'Cat'), (2, 'Bird'), (3, 'Fish')]