first function

# define the function
def hello_func():
	pass # do not do anything with this for now but it won't throw any errors for leaving it blank

hello_func() # run the function

# define the function
def hello_func():
	print("hello function!")
	
hello_func() # run the function

'''
out:
hello function!
'''

return

# define the function
def hello_func():
	return "hello function!"

hello_func() # run the function
'''
out:
[Finished in 53ms]
'''
print(hello_func())
'''
out:
hello function!
[Finished in 52ms]
'''

parameters

def hello_func(gretting):
	return '{} function!'.format(gretting)

print(hello_func('hello'))
'''
out:
hello function!
[Finished in 56ms]
'''

parameters with default value

def hello_func(gretting, name='you'):
	return '{}, {}!'.format(gretting,name)

print(hello_func('hello'))
'''
out:
hello, you!
[Finished in 56ms]
'''
print(hello_func('hello','Eric'))
'''
hello, Eric!
'''

*args **kwargs

接收任意数量的

def student_info(*args, **kwargs):
	print(args)
	print(kwargs)
student_info('Math', 'Art', name='John', age=22)

'''
out:
('Math', 'Art')
{'name': 'John', 'age': 22}
[Finished in 53ms]
'''

#--------
def student_info(*args, **kwargs):
	print(args)
	print(kwargs)

courses = ['Math', 'Art']
info = {'name': 'John', 'age': 22}
student_info(courses, info)
'''
out:
(['Math', 'Art'], {'name': 'John', 'age': 22})
{}
'''
student_info(***courses, **info**)
'''
out:
('Math', 'Art')
{'name': 'John', 'age': 22}
[Finished in 53ms]
'''

simple sample

month_days = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

def is_leap(year):
	'''Return True or False for leap years or non-leap years.'''
	return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)

def days_in_month(year, month):
	'''Return number of days in that month in that year.'''
	if not 1 <= month <= 12:
		return 'Invalid month'
	if month == 2 and is_leap(year):
		return 29
	return month_days[month]

print(is_leap(2017))
print(is_leap(2020))

print(days_in_month(2017,2))
print(days_in_month(2020,2))

'''
out:
False
True
28
29
[Finished in 54ms]
'''