Question

我是Python新手而且卡住了。我怎么写这个？＆＃34;写一个for循环来对前10个非零整数求和＆＃34;

Answer 1

一步一步地采取行动：

# example list of 14 elements, 11 elements are non-zero 
mylist = [0, 4, 17, 2, 14, 3, 8, 0, 2, 1, 0, 7, 5, 5] 
# non-zero   1   2  3   4  5  6     7  8     9 10  

# initialize variables
mysum = 0 
count = 1 # counter until we get to 10

for x in mylist:                # for each item in the list
    if x != 0 and count <= 10:  # if both conditions are satisfied
        mysum += x              # add the item to the sum
        count += 1              # increase the counter until we reach 10

print mysum

输出：

对于这个例子，它排除了最后的5，因为我们只考虑前10个非零元素

Answer 2

如果列表在第10个非零整数之后并没有那么大，那么我会删除所有的零，并在前10个数字的切片上调用sum：

mylist = [0, 4, 17, 2, 14, 3, 8, 0, 2, 1, 0, 7, 5, 5] 

total = sum([ n for n in mylist if n > 0 ][:10])
print(total)

过滤和控制for循环列表中要求的项数 - Python

2 个答案: