Eighth: function的定义及调用

# basic function
def fib(n):
    a, b, result = 0, 1, []
    while a < n:
        result.append(a)
        a, b = b, a+b
    return result

print(‘fib(10)=‘,fib(10))

# function with default argument values
def sum(x, y=0):
    return x + y

print(‘sum(2)=‘,sum(2))    
print(‘sum(2,5)=‘,sum(2,5))
print(‘sum("2","5")=‘,sum(‘2‘,‘5‘))


# The value of the function name has a type that is recognized by the interpreter as a user-defined function. 
# This value can be assigned to another name which can then also be used as a function.
fib_copy = fib
print(‘fib_copy(10)=‘,fib_copy(10))

"""
    function with default argument values
"""
def full_name(first_name=‘Miles‘, middle_name=‘M‘, last_name=‘Yao‘):
    return first_name + ‘ ‘ + middle_name + ‘ ‘ + last_name

print(‘full_name()=‘,full_name())
print(‘full_name("Miles")=‘,full_name(‘Miles‘))
print(‘full_name("Miles","MM")=‘,full_name(‘Miles‘,‘MM‘))

print("full_name(last_name=‘Lee‘, middle_name=‘XX‘)=",full_name(last_name=‘Lee‘, middle_name=‘XX‘))

polulation = 5

def f_population(arg=polulation):
    print(arg)

polulation = 6
# the print value would be 6
f_population()    

def f_list(i, _list=[]):
    _list.append(i)
    return _list

print(‘f_list(1)=‘,f_list(1))    
print(‘f_list(2)=‘,f_list(2))
print(‘f_list(3)=‘,f_list(3))

‘‘‘
    Arbitrary Argument Lists
‘‘‘

def concat_a(*args, seperate=‘/‘):
        return seperate.join(args)

print("concat_a(‘hello‘,‘world‘)=",concat_a(‘hello‘,‘world‘))
print("concat_a(‘hello‘,‘world‘, seperate=‘:‘=",concat_a(‘hello‘,‘world‘, seperate=‘:‘))



‘‘‘
    dictionaries can deliver keyword arguments with the **-operator:
‘‘‘

print(‘sum(**{"x":12, "y":15})=‘,sum(**{"x":12, "y":15}))