lambda λ函式

功能：具有函式功能且一行就能使用，可接受任意數量的參數
double

def double(x):
    return x * 2
    
print(double(10))


20

lambda λ改寫

double2 = lambda x: x*2
print(double2(50))


100

傳入多個參數

mutiply = lambda x, y: x * y
print(mutiply(5, 10))


50

if, else條件語句

result = lambdax: f"{x}是偶數" if x % 2 == 0 else f"{x}是奇數"
print(result(15))


15 是奇數

處理字串方式

full_name = lambda first_name, last_name: f"{first_name} {last_name}"
print(full_name("Jemmy", "Wang"))


Jemmy Wang

map

map(函式,可迭代列表[])

store = [
    ('襯衫‘, 20) #美元
    ('褲子', 30)
    ('夾克', 50)
    ('襪子', 10)
]
#美元轉歐元
to_euros = lambda date: (date[0], date[] * 0.82)
store_euros = list(map(to_euros, store))
print(store_euros)


[('襯衫', 16.4), ('褲子', 24.599999999999998), ('夾克', 41.0), ('襪子', 8.2)]

store = [
    ('襯衫‘, 600) #台幣
    ('褲子', 1200)
    ('夾克', 1600)
    ('襪子', 200)
]
#新台幣轉美金
to_usd = lambda date: (date[0], round(date[1] / 30)
store_usds = list(map(to_usd, store))
for item in store_usds:
    print(item)

('襯衫', 20)
('褲子', 40)
('夾克', 53)
('襪子', 7)

filter 過濾函式

功能：過濾可迭代的物件，如：列表list

friend = [
    ('Bob', 18)
    ('Steven', 17)
    ('Micheal', 19)
    ('Susan', 16)
]

age_filter = lambda date: date[1] >= 18
can_drink_friends = list(filter(age_filter, friend))
for friend in can_drink_friends:
    print(friend[0])
    print(friend[1])
    
    
Bob
18
Micheal
19