Python基础-4 使用函数减少重复操作

print("5月10号")
print("去水果店")
print("买苹果，花费5.2元")

print("5月11号")
print("去水果店")
print("买橘子，花费6元")

print("5月12号")
print("去超市")
print("买牛奶，花费60元")

def record_consume(date, place, item, price):
    print(date)
    print(f"去{place}")
    print(f"买{item}，花费{price}元")


record_consume("5月10日", "水果店", "苹果", 5.2)
record_consume("5月11日", "水果店", "橘子", 6)
record_consume("5月12日", "超市", "牛奶", 60)

def record_consume(date, place, item, price):
    """记账函数，传入参数日期，地点，物品，价格"""
    print(date)
    print(f"去{place}")
    print(f"买{item}，花费{price}元")

record_consume("5月10日", "水果店", "苹果", 5.2)

def 函数名(参数列表):
    函数内容

def distance_to_avg(scores):
    """计算到平均值的差值"""
    avg = sum(scores) / len(scores)
    return [x - avg for x in scores]


scores = [90, 80, 70, 80, 90]
distances = distance_to_avg(scores) # 将返回的列表赋值给distances变量
print(distances)

def 函数名(必选参数，默认值参数=默认值):

def calculate_list_sta(list_a, mood='avg'):
    if mood == 'avg':
        return sum(list_a) / len(list_a)
    elif mood == 'sum':
        return sum(list_a)
    else:
        return -1

scores = [90, 80, 70, 80, 90]
avg = calculate_list_sta(scores)
s = calculate_list_sta(scores,"sum")
print(avg,s)

i = 5

def f(arg=i):
    print(arg)

i = 6
f()  # 5

def f(a, L=[]):
    L.append(a)
    return L

print(f(1)) #[1]
print(f(2)) #[1, 2]
print(f(3)) #[1, 2, 3]

def f(a, L=None):
    if L is None:
        L = []
    L.append(a)
    return L

print(calculate_list_sta(scores, 'sum'))
print(calculate_list_sta(list_a=scores, mood='sum'))
print(calculate_list_sta(mood='sum', list_a=scores))
print(calculate_list_sta(mood='sum',scores)) # 错误，位置参数必须在关键字参数前

def cheeseshop(kind, *arguments, **keywords):
    print("-- Do you have any", kind, "?")
    print("-- I'm sorry, we're all out of", kind)
    for arg in arguments:
        print(arg)
    print("-" * 40)
    for kw in keywords:
        print(kw, ":", keywords[kw])

cheeseshop("Limburger", "It's very runny, sir.",
           "It's really very, VERY runny, sir.",
           shopkeeper="Michael Palin",
           client="John Cleese",
           sketch="Cheese Shop Sketch")

-- Do you have any Limburger ?
-- I'm sorry, we're all out of Limburger
It's very runny, sir.
It's really very, VERY runny, sir.
----------------------------------------
shopkeeper : Michael Palin
client : John Cleese
sketch : Cheese Shop Sketch

def standard_arg(arg):
    print(arg)

standard_arg(2)
standard_arg(arg=2)


def pos_only_arg(arg, /):
    print(arg)

pos_only_arg(1)
pos_only_arg(arg=1)    #报错，只能通过位置传参，不能用关键字传参


def kwd_only_arg(*, arg):
    print(arg)

kwd_only_arg(3)     #报错，只能关键字传参
kwd_only_arg(arg=3)


# /前面仅位置传参，*后面仅关键字，standard不受约束
def combined_example(pos_only, /, standard, *, kwd_only):
    print(pos_only, standard, kwd_only)

combined_example(1, 2, kwd_only=3)  
combined_example(1, standard=2, kwd_only=3)

def foo(name, **kwds):
    return 'name' in kwds
foo(1, **{'name': 2}) # 冲突，1会先传递给name,{'name':2}会以关键字方式再传递给name

def foo(name, /, **kwds):
    return 'name' in kwds
print(foo(1, **{'name': 2}))

def write_multiple_items(file, separator, *args):
    file.write(separator.join(args))

def concat(*args, sep="/"):
    return sep.join(args)

concat("earth", "mars", "venus")
concat("earth", "mars", "venus", sep=".")

list(range(3, 6))            # 正常调用，使用两个参数

args = [3, 6]
list(range(*args))            # 使用解包(unpack)，两个参数从列表中取出

def parrot(voltage, state='a stiff', action='voom'):
    print("-- This parrot wouldn't", action, end=' ')
    print("if you put", voltage, "volts through it.", end=' ')
    print("E's", state, "!")

d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
parrot(**d)

pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
pairs.sort(key=lambda pair: pair[1])
pairs

def my_function():
    """Do nothing, but document it.

    No, really, it doesn't do anything.
    """
    pass

print(my_function.__doc__)

#输出：
Do nothing, but document it.

    No, really, it doesn't do anything.

def 函数名(形参: 参数类型, 关键字参数: 参数类型 = '默认值') -> 返回值类型:

def f(ham: str, eggs: str = 'eggs') -> str:
    print("Annotations:", f.__annotations__)
    print("Arguments:", ham, eggs)
    return ham + ' and ' + eggs