# 求数组元素的和
from functools import reduce
def add(x, y):
return x + y
s = reduce(add, [1, 3, 5, 7, 9])
print(s)
25
# 将元素转换为一个数字
from functools import reduce
def f(x, y):
return x * 10 + y
num = reduce(f, [1, 3, 5, 7, 9])
print(num)
13579
from functools import reduce
def f(x, y):
return x * 10 + y
def cha_to_num(s):
digits = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5,
'6': 6, '7': 7, '8': 8, '9': 9}
return digits[s]
# 将字符串转换为整数
num = reduce(f, map(cha_to_num, '13579'))
print(num)
13579
from functools import reduce
def cha_to_num(s):
digits = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5,
'6': 6, '7': 7, '8': 8, '9': 9}
return digits[s]
num = reduce(lambda x, y: x * 10 + y, map(cha_to_num, '13579'))
print(num)
13579
def normalize(name):
return name.title()
# 测试:
L1 = ['adam', 'LISA', 'barT']
# 用户输入的不规范的英文名字,变为首字母大写,其他小写的规范名字
L2 = list(map(normalize, L1))
print(L2)
['Adam', 'Lisa', 'Bart']
from functools import reduce
def prod(L):
return reduce(lambda x, y: x * y, L)
print('3 * 5 * 7 * 9 =', prod([3, 5, 7, 9]))
if prod([3, 5, 7, 9]) == 945:
print('测试成功!')
else:
print('测试失败!')
3 * 5 * 7 * 9 = 945
测试成功!
# 将浮点数转换为整数
from functools import reduce
def str2float(s):
# 将浮点数分成整数部分和小数部分
s_list = s.split('.')
num1 = reduce(lambda x, y: int(x) * 10 + int(y), s_list[0])
num2 = reduce(lambda x, y: float(x) * 0.1 + float(y), s_list[-1][::-1])
return num1 + num2*0.1
print('str2float(\'123.456\') =', str2float('123.456'))
if abs(str2float('123.456') - 123.456) < 0.00001:
print('测试成功!')
else:
print('测试失败!')
str2float('123.456') = 123.456
测试成功!