问题2: 对一组整数求和:

a = [2, 3, 5, 8]
sum(a)
# 18
# or you can do:
sum(i for i in a)
# 18

如果列表中包含整数作为字符串:

a = ['5', '6']
# import Decimal: from decimal import Decimal
sum(Decimal(i) for i in a)

使用简单的列表-理解和求和:

>> sum(i for i in range(x))/2. #if x = 10 the result will be 22.5

n = int(input("Enter the length of array: "))
list1 = []
for i in range(n):
    list1.append(int(input("Enter numbers: ")))
print("User inputs are", list1)

list2 = []
for j in range(0, n-1):
    list2.append((list1[j]+list1[j+1])/2)
print("result = ", list2)

生成器是一种简单的编写方法:

from __future__ import division
# ^- so that 3/2 is 1.5 not 1

def averages( lst ):
    it = iter(lst) # Get a iterator over the list
    first = next(it)
    for item in it:
        yield (first+item)/2
        first = item

print list(averages(range(1,11)))
# [1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5]

使用成对的itertools食谱:

import itertools
def pairwise(iterable):
    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
    a, b = itertools.tee(iterable)
    next(b, None)
    return itertools.izip(a, b)

def pair_averages(seq):
    return ( (a+b)/2 for a, b in pairwise(seq) )

问题2: 对一组整数求和:

a = [2, 3, 5, 8]
sum(a)
# 18
# or you can do:
sum(i for i in a)
# 18

如果列表中包含整数作为字符串:

a = ['5', '6']
# import Decimal: from decimal import Decimal
sum(Decimal(i) for i in a)