8000 Merge pull request #8 from tecladocode/lambda_function_improvements · coding794/complete-python-course@d5a1ef1 · GitHub
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Merge pull request tecladocode#8 from tecladocode/lambda_function_improvements
Add improvements as discussed with Phil
2 parents 2bb8298 + 9df8eb8 commit d5a1ef1

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  • course_contents
    • 10_advanced_python/lectures/16_higher_order_functions
    • 2_intro_to_python/lectures

9 files changed

+124
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‎course_contents/10_advanced_python/lectures/16_higher_order_functions/code.py

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# `before_and_after` is a higher-order function. That just means it's a function which has another function as a parameter.
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def before_and_after(func): # func is a function passed
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print("Before...")
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func()
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print("After...")
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# greet, not greet(). That's because we're passing the function, not the result of calling the function.
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before_and_after(greet)
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# Another example
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movies = [
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{"name": "The Matrix", "director": "Wachowski"},
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{"name": "A Beautiful Day in the Neighborhood", "director": "Heller"},
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{"name": "The Irishman", "director": "Scorsese"},
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{"name": "Klaus", "director": "Pablos"},
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{"name": "1917", "director": "Mendes"},
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]
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def find_movie(expected, finder):
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found = []
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for movie in movies:
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if finder(movie) == expected:
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found.append(movie)
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return found
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find_by = input("What property are we searching by? ")
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looking_for = input("What are you looking for? ")
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movie = find_movie(looking_for, lambda x: x[find_by])
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print(movie or 'No movies found.')
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‎course_contents/2_intro_to_python/lectures/14_enumerate/code.py

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# https://blog.tecladocode.com/python-enumerate/
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friends = ["Rolf", "John", "Anna"]
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for counter, friend in enumerate(friends, start=1):
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print(counter, friend)
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# 1 Rolf
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# 2 John
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# 3 Anna
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friends = ["Rolf", "John", "Anna"]
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print(list(enumerate(friends))) # [(0, 'Rolf'), (1, 'John'), (2, 'Anna')]
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print(dict(enumerate(friends))) # {0: 'Rolf', 1: 'John', 2: 'Anna'}

‎course_contents/2_intro_to_python/lectures/14_functions/code.py renamed to ‎course_contents/2_intro_to_python/lectures/15_functions/code.py

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‎course_contents/2_intro_to_python/lectures/15_arguments_and_parameters/code.py renamed to ‎course_contents/2_intro_to_python/lectures/16_arguments_and_parameters/code.py

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‎course_contents/2_intro_to_python/lectures/16_return_values/code.py renamed to ‎course_contents/2_intro_to_python/lectures/17_return_values/code.py

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‎course_contents/2_intro_to_python/lectures/17_default_parameter_values/code.py renamed to ‎course_contents/2_intro_to_python/lectures/18_default_parameter_values/code.py

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‎course_contents/2_intro_to_python/lectures/19_first_class_higher_order_functions/code.py

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‎course_contents/2_intro_to_python/lectures/18_lambda_functions/code.py renamed to ‎course_contents/2_intro_to_python/lectures/19_lambda_functions/code.py

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‎course_contents/2_intro_to_python/lectures/20_first_class_functions/code.py

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# In Python, functions are first class citizens.
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# That means that, just like any other value, they can be passed as arguments to functions or assigned to variables.
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# Here's a simple (yet not terribly useful) example to illustrate it:
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def greet():
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print("Hello!")
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hello = greet # hello is another name for the greet function now.
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hello()
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# Let's move on to a more useful example.
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# These don't _have_ to be lambdas. They could be normal functions too!
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# I'm making them lambdas because they're really short.
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avg = lambda seq: sum(seq) / len(seq)
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total = lambda seq: sum(seq) # could just be `sum`
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top = lambda seq: max(seq) # could just be `max`
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students = [
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{"name": "Rolf", "grades": (67, 90, 95, 100)},
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{"name": "Bob", "grades": (56, 78, 80, 90)},
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{"name": "Jen", "grades": (98, 90, 95, 99)},
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{"name": "Anne", "grades": (100, 100, 95, 100)},
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]
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for student in students:
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name = student["name"]
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grades = student["grades"]
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print(f"Student: {name}")
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operation = input("Enter 'average', 'total', or 'top': ")
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if operation == "average":
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print(avg(grades))
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elif operation == "total":
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print(total(grades))
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elif operation == "top":
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print(top(grades))
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# Here, you can see how we can store functions inside a dictionary—just as we could do with numbers, strings, or any other type of data.
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# We're creating a dictionary of what would be user input to the function that we want to run in each case.
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operations = {
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"average": avg,
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"total": total, # could just be `sum`
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"top": top, # could just be `max`
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}
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# The `operations` dictionary could also be defined inline:
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operations = {
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"average": lambda seq: sum(seq) / len(seq),
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"total": lambda seq: sum(seq), # could just be `sum`
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"top": lambda seq: max(seq), # could just be `max`
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}
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# The rest of the code can make use of the `operations` dictionary
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for student in students:
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name = student["name"]
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grades = student["grades"]
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print(f"Student: {name}")
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operation = input("Enter 'average', 'total', or 'top': ")
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operation_function = operations[operation] # This means we don't need an if statement (but could get errors!)
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print(operation_function(grades))
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