vcs/_4.python/function/test_lambda.py at master · bunshue/vcs · GitHub

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print("------------------------------------------------------------") # 60個

# 函數: 計算2個參數和

def sum(a, b):

return a + b

# 建立匿名函數

square = lambda x: x * x

# 將變數指定成函數

total = sum

r = square(10) # 呼叫匿名函數

print("square(10) = ", r)

r = sum(10, 5) # 呼叫函數

print("sum(10, 5) = ", r)

r = total(10, 5) # 使用變數呼叫函數

print("total(10, 5) = ", r)

print("------------------------------------------------------------") # 60個

# 定義lambda函數

square = lambda x: x**2

# 輸出平方值

print(square(10))

print("------------------------------------------------------------") # 60個

# lambda : 只有單一運算式的匿名函式

add = lambda x, y: x + y # 冒號前是參數, 冒號後是運算式

cc = add(3, 5)

print("使用 lambda 做加法:", cc)

print("------------------------------------------------------------") # 60個

from functools import reduce

def strToInt(s):

def charToNum(s):

return {

"0": 0,

"1": 1,

"2": 2,

"3": 3,

"4": 4,

"5": 5,

"6": 6,

"7": 7,

"8": 8,

"9": 9,

}[s]

return reduce(lambda x, y: 10 * x + y, map(charToNum, s))

string = "5487"

x = strToInt(string) + 10

print("x = ", x)

print("------------------------------------------------------------") # 60個

str_len = lambda x: len(x)

strs = ["abc", "ab", "abcde"]

strs.sort(key=str_len)

print(strs)

print("------------------------------------------------------------") # 60個

strs = ["abc", "ab", "abcde"]

strs.sort(key=lambda x: len(x))

print(strs)

print("------------------------------------------------------------") # 60個

sc = [["John", 80], ["Tom", 90], ["Kevin", 77]]

sc.sort(key=lambda x: x[1])

print(sc)

print("------------------------------------------------------------") # 60個

sc = [["John", 80], ["Tom", 90], ["Kevin", 77]]

newsc = sorted(sc, key=lambda x: x[1])

print(newsc)

print("------------------------------------------------------------") # 60個

sc = {"John": 80, "Tom": 90, "Kevin": 77}

newsc1 = sorted(sc.items(), key=lambda x: x[0]) # 依照key排序

print("依照人名排序")

print(newsc1)

newsc2 = sorted(sc.items(), key=lambda x: x[1]) # 依照value排序

print("依照分數排序")

print(newsc2)

print("------------------------------------------------------------") # 60個

mylist = [5, 10, 15, 20, 25, 30]

evenlist = list(filter(lambda x: (x % 2 == 0), mylist))

# 輸出偶數串列

print("偶數串列: ", evenlist)

print("------------------------------------------------------------") # 60個

result = lambda x: 3 * x - 1 # lambda()函數

print(result(3)) # 輸出數值8

print("------------------------------------------------------------") # 60個

def formula(x, y): # 自訂函數

return 3 * x + 2 * y

formula = lambda x, y: 3 * x + 2 * y # 表示lambda有二個參數

print(formula(5, 10)) ##傳入兩個數值讓lambda()函數做運算，輸出數值35

print("------------------------------------------------------------") # 60個

# lambda 函式簡介

power = lambda x: x**2

print(power(10))

add = lambda a, b: a + b

print(add(5, 3))

print("------------------------------------------------------------") # 60個

# 定義lambda函數

square2 = lambda x: x**2

# 輸出平方值

print(square2(10))

print("------------------------------------------------------------") # 60個

total = lambda a, b: a + b

num1 = 0

num2 = 0

num1 = 123

num2 = 456

print("數值 1+數值 2 =", total(num1, num2))

# 在 lambda 內使用一行 if 條件判斷式

absolute = lambda x: x if x >= 0 else -x

func = lambda x: (x**2 - 40 * x + 350) if 10 <= x < 30 else 50

# str.split()：分割字串為 list 元素

sentence = "This is a test sentence"

print(sentence.split(" "))

["This", "is", "a", "test", "sentence"]

print("------------------------------------------------------------") # 60個

# 用 flter() 篩選容器元素

str_list = ["This", "is", "a", "test", "sentence"]

print(list(filter(lambda x: len(x) >= 3, str_list)))

["This", "test", "sentence"]

# 再探 sorted()：自訂目標容器的排序方式

str_list = ["This", "is", "a", "test", "sentence"]

print(sorted(str_list, key=len, reverse=True))

nest_list = [[0, 9], [1, 8], [2, 7], [3, 6], [4, 5]]

print(sorted(nest_list))

print(sorted(nest_list, key=lambda x: x[1]))

print(sorted(nest_list, key=lambda x: x[1], reverse=True))

print("------------------------------------------------------------") # 60個

mylist = [5, 10, 15, 20, 25, 30]

oddlist = list(filter(lambda x: (x % 2 == 1), mylist))

# 輸出奇數串列

print("奇數串列: ", oddlist)

print("------------------------------------------------------------") # 60個

mylist = [5, 10, 15, 20, 25, 30]

squarelist = list(map(lambda x: x**2, mylist))

# 輸出串列元素的平方值

print("串列的平方值: ", squarelist)

print("------------------------------------------------------------") # 60個

cal_dict = {

"加": lambda x, y: x + y,

"減": lambda x, y: x - y,

"乘": lambda x, y: x * y,

"除": lambda x, y: x / y,

}

def calculator(x, operator, y):

return cal_dict.get(operator, lambda: None)(x, y)

print(calculator(6, "乘", 7))

calculator = {

"加": lambda x, y: x + y,

"減": lambda x, y: x - y,

"乘": lambda x, y: x * y,

"除": lambda x, y: x / y,

}

default = lambda: None

print(calculator.get("加", default)(1, 2))

print(calculator.get("乘", default)(3, 5))

print("------------------------------------------------------------") # 60個

print("作業完成")

print("------------------------------------------------------------") # 60個

vcs/_4.python/function/test_lambda.py at master · bunshue/vcs · GitHub

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