#函數(shù)參數(shù)

# 位置參數(shù)
# 計算一個數(shù)的平方
def power(x):
    return x*x

# 計算一個數(shù)的n次方
def powers(x,n):
    s = 1
    while n > 0:
        n = n - 1
        s = s * x
    return s

#默認參數(shù)
# 必選參數(shù)在前面，默認參數(shù)在后面
# 多個參數(shù)時：變化大的參數(shù)在前面，變化小的參數(shù)在后面。
def powerA(x, n=2):
    s = 1
    while n > 0:
        n = n - 1
        s = s * x
    return s
# 學生注冊函數(shù)
def eroll(name, gender):
    print('name:',name)
    print('gender:',gender)
eroll('Sarah','F')
# name: Sarah
# gender: F
#上面的函數(shù) 繼續(xù)傳入 年齡，城市信息
def erollA(name, gender, age = 6, city = 'Beijing'):
    print('name:',name)
    print('gender:',gender)
    print('age:',age)
    print('city:',city)

erollA('Tim','A')
# name: Tim
# gender: A
# age: 6
# city: Beijing

erollA('Bob','M',7)
# 不按照 默認參數(shù)順序傳入，直接寫上對應參數(shù)名
erollA('Adam','M',city='Tianjin')

#默認參數(shù)的坑
# 在傳入list 后面加上 END
def add_end(L=[]):
    L.append('END')
    return L

#abc =  add_end([1,2,3])#[1, 2, 3, 'END']
add_end()
add_end()#['END', 'END']
#連續(xù)調(diào)用兩次 add_end() 函數(shù)后， 會出現(xiàn)不正確的結(jié)果
# 因此，默認參數(shù)必須是不可變對象

#上面的函數(shù) 優(yōu)化一下
def add_endA(L=None):
    if L is None:
        L = []
    L.append('END')
    return L
# 這下無論調(diào)用多少次都不會出問題了


# 可變參數(shù)
# 允許你傳入 0 個或者任意個參數(shù)
# 給定一組數(shù)字，a, b, c .... 計算 a^2 + b^2 + c^2 + ,,,,,,
def calc(numbers):
    sum = 0
    for n in numbers:
        sum = sum + n * n
    return sum
jkj = calc([1,2,3,4])#30
jkj = calc([1,3,5,7])#84

# 把上面的函數(shù)修改為可變參數(shù)
def calcA(*numbers):# numbers 相當于 tuple
    sum = 0
    for n in numbers:
        sum = sum + n * n
    return sum
calcA(1,2)#5
calcA()#0

nums = [1,2,3]
calcA(*nums)# 可以在 list tuple 前面加上*號，當做可變參數(shù)傳入
nums = (1,2,3)
calcA(*nums)



# 關(guān)鍵字參數(shù)
# 允許你傳入 0 個 或者人一個含參數(shù)名的參數(shù)， 這些關(guān)鍵字參數(shù)在函數(shù)內(nèi)部自動組裝成一個dict
def person(name, age, **kw):
    print('name:',name,'age:',age,'other:',kw)

# 只傳入必選參數(shù)
person('Michael', 30)#name: Michael age: 30 other: {}
#傳入任意個數(shù)的關(guān)鍵字參數(shù)
person('Bob',35,city='Beijing')#name: Bob age: 35 other: {'city': 'Beijing'}

#也可以先組裝成一個dict 然后把該dict 轉(zhuǎn)換為關(guān)鍵字傳進去
extra = {'city':'Beijing','Job':'Engineer'}
person('Jack',24,**extra)#name: Jack age: 24 other: {'city': 'Beijing', 'Job': 'Engineer'}
# 函數(shù)內(nèi)對 extra 的拷貝 進行處理， 不會影響到 extra本身

#命名關(guān)鍵字參數(shù)
def personY(name, age, **kw):
    if 'city' in kw:
        #說明有 city 參數(shù)
        pass
    if 'job' in kw:
        # 說明有job參數(shù)
        pass
    print('name:',name, 'age:',age,'other:',kw)
# 調(diào)用者可以傳入不受限制的關(guān)鍵字參數(shù)
personY('Jack',24,city = 'Beijing', addr = 'Chaoyang',zipcode=123456)
# name: Jack age: 24 other: {'city': 'Beijing', 'addr': 'Chaoyang', 'zipcode': 123456}

# 限制關(guān)鍵字參數(shù)的名字 需要用到 * 號， * 號 后面的參數(shù)被視為命名關(guān)鍵字參數(shù)
# 所有參數(shù)都必須傳入， 不然會報錯
# 關(guān)鍵字參數(shù)必須傳入?yún)?shù)名字
def personX(name, age, * ,city, job):
    print(name, age, city, job)
personX('Jack',24,city = 'Beijing',job='Enginner')

# 如果函數(shù)中有一個可變參數(shù)， 后面跟著的命名參數(shù)不需要 * 來分隔了
def personZ(name, age, *args, city, job):
    print(name, age, args, city, job)
personZ('Jack',24,city='Beijing',job='Enginner')

#命名關(guān)鍵字 缺省
def personT(name, age, *  , city='Beijing',job):
    print(name,age,city,job)
personT('Jack',24,job='Enginner')

#參數(shù)組合， 順序為 必選參數(shù)，默認參數(shù)，可變參數(shù)，關(guān)鍵字參數(shù)，命名關(guān)鍵字參數(shù)
def f1(a, b, c = 0, *args, **kwargs):
    print('a = ',a,'b = ',b, 'c = ',c, 'args = ',args, 'kargs = ',kwargs )

def f2(a,b,c=0,*,d,**kwargs):
    print('a = ',a, 'b =  ',b, 'c = ',c, 'd = ',d, 'kwargs = ',kwargs)

f1(1,2)
#a =  1 b =  2 c =  0 args =  () kargs =  {}
f1(1,2,c=3)
#a =  1 b =  2 c =  3 args =  () kargs =  {}
f1(1,2,3,'a','b')
#a =  1 b =  2 c =  3 args =  ('a', 'b') kargs =  {}
f1(1,2,3,'a','b',x=99)
#a =  1 b =  2 c =  3 args =  ('a', 'b') kargs =  {'x': 99}
f2(1,2,d=99,extra = None)
#a =  1 b =   2 c =  0 d =  99 kwargs =  {'extra': None}

# 通過一個tupel 和 dict 也可以像上面那樣傳參
args = (1,2,3,4)
kw = {'d':99,'x':'#'}
f1(*args,**kw)
#a =  1 b =  2 c =  3 args =  (4,) kargs =  {'d': 99, 'x': '#'}
args = (1,2,3)
kw = {'d':88,'x':'#'}
f2(*args,**kw)
#a =  1 b =   2 c =  3 d =  88 kwargs =  {'x': '#'}

# 所有任意函數(shù) 都可以通過類似func(*args,**kw)的形式調(diào)用。