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Read sections 16.1, 16.2, 16.3, and 16.4 in the book and try out the code samples. You don't have to do any of the exercises.
When you have a function that takes an object parameter, you can access all the attributes of that object. We saw this last time in print_recipe:
def print_recipe(recipe):
"""Nicely prints a Recipe object."""
print("Recipe:", recipe.name)
print() #Add a blank line
print("Ingredients:")
for ingredient in recipe.ingredients:
print(" *", ingredient)
print() #another blank line
print("Steps:")
for i in range(len(recipe.steps)):
step = recipe.steps[i]
print(" " + str(i) + ":", step)
Let's create some other functions that take Recipe objects.
def num_steps(recipe):
"""Returns the number of steps in a recipe."""
return len(recipe.steps)
We can have functions that return a Recipe also:
def has_more_ingredients(recipe_0, recipe_1):
"""Returns the recipe with more ingredients."""
if len(recipe_0.ingredients) < len(recipe_1.ingredients):
return recipe_1
else:
return recipe_0
Try these out with the recipes we created last time:
>>> fake_chx_parm = Recipe()
>>> fake_chx_parm.name = "Microwave Chicken Parm"
>>> fake_chx_parm.ingredients = []
>>> fake_chx_parm.steps = []
>>> fake_chx_parm.ingredients.append("5 frozen chicken nuggets")
>>> fake_chx_parm.ingredients.append("1/3 cup pasta sauce")
>>> fake_chx_parm.ingredients.append("1 provolone slice")
>>> fake_chx_parm.steps.append("Microwave the frozen chicken nuggets in a small bowl for 1 minute, 25 seconds.")
>>> fake_chx_parm.steps.append("Pour the pasta sauce over one side of the heated nuggets.")
>>> fake_chx_parm.steps.append("Place the provolone slice over the pasta sauce.")
>>> fake_chx_parm.steps.append("Put everything back in the microwave for 25 more seconds, then enjoy!")
>>>
>>> cup = Recipe()
>>> cup.name = "PB Cup"
>>> cup.ingredients = ["Peanut Butter Cup"]
>>> cup.steps = ["Unwrap it and eat."]
>>> recipe = has_more_ingredients(fake_chx_parm, cup)
>>> recipe.name
'Microwave Chicken Parm'
>>> num_steps(cup)
1
>>>