Open file data/unsorted_names.txt in data folder. Sort the names and write them to a new file called sorted_names.txt. Each name should start with a new line as in the following example:

Adele
Adrienne
...
Willodean
Xavier

Implement a function which search for most common words in the file. Use data/lorem_ipsum.txt file as a example.

def most_common_words(filepath, number_of_words=3):
    pass

print(most_common_words('lorem_ipsum.txt'))
>>> ['donec', 'etiam', 'aliquam']

NOTE: Remember about dots, commas, capital letters etc.

File data/students.csv stores information about students in CSV format. This file contains the student’s names, age and average mark.

1. Implement a function which receives file path and returns names of top performer students

def get_top_performers(file_path, number_of_top_students=5):
    pass

print(get_top_performers("students.csv"))
>>> ['Teresa Jones', 'Richard Snider', 'Jessica Dubose', 'Heather Garcia', 'Joseph Head']

2. Implement a function which receives the file path with students info and writes CSV student information to the new file in descending order of age. Result:

student name,age,average mark
Verdell Crawford,30,8.86
Brenda Silva,30,7.53
...
Lindsey Cummings,18,6.88
Raymond Soileau,18,7.27

Look through file modules/legb.py.

1. Find a way to call inner_function without moving it from inside of enclosed_function.

2.1) Modify ONE LINE in inner_function to make it print variable 'a' from global scope.

2.2) Modify ONE LINE in inner_function to make it print variable 'a' form enclosing function.

Implement a decorator remember_result which remembers last result of function it decorates and prints it before next call.

@remember_result
def sum_list(*args):
	result = ""
	for item in args:
		result += item
	print(f"Current result = '{result}'")
	return result

sum_list("a", "b")
>>> "Last result = 'None'"
>>> "Current result = 'ab'"
sum_list("abc", "cde")
>>> "Last result = 'ab'" 
>>> "Current result = 'abccde'"
sum_list(3, 4, 5)
>>> "Last result = 'abccde'" 
>>> "Current result = '12'"

Implement a decorator call_once which runs a function or method once and caches the result. All consecutive calls to this function should return cached result no matter the arguments.

@call_once
def sum_of_numbers(a, b):
    return a + b

print(sum_of_numbers(13, 42))
>>> 55
print(sum_of_numbers(999, 100))
>>> 55
print(sum_of_numbers(134, 412))
>>> 55
print(sum_of_numbers(856, 232))
>>> 55

Run the module modules/mod_a.py. Check its result. Explain why does this happen. Try to change x to a list [1,2,3]. Explain the result. Try to change import to from x import * where x - module names. Explain the result.

• Decorators
• Decorators in python
• Python imports
• Files in python