Python - 识别列表中的负数
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Python - Identify a negative number in a list
提问by Michael
I need help doing a program which should recieve ten numbers and return me the number of negative integers i typed. Example: if i enter:
我需要帮助做一个程序，它应该接收十个数字并返回我输入的负整数的数量。示例：如果我输入：
1,2,-3,3,-7,5,4,-1,4,5
the program should return me 3.
I dont really have a clue, so please give me a hand :)
PS. Sorry for my bad english, I hope you understand
该程序应该返回我3。我真的不知道，所以请帮我一把:) PS。抱歉我的英语不好，希望你能理解
采纳答案by Gareth Latty
Break your problem down. Can you identify a way to check if a number is negative?
分解你的问题。你能找出一种方法来检查一个数字是否为负数吗？
if number < 0:
...
Now, we have many numbers, so we loop over them:
现在，我们有很多数字，所以我们遍历它们：
for number in numbers:
if number < 0:
...
So what do we want to do? Count them. So we do so:
那么我们想要做什么呢？数一数他们。所以我们这样做：
count = 0
for number in numbers:
if number < 0:
count += 1
More optimally, this can be done very easily using a generator expressionand the sum()built-in:
更理想的是，这可以使用生成器表达式和内置的很容易地完成：sum()
>>> numbers = [1, 2, -3, 3, -7, 5, 4, -1, 4, 5]
>>> sum(1 for number in numbers if number < 0)
3
回答by squiguy
回答by jamylak
sum(n < 0 for n in nums)
This is the most pythonic way to do it.
这是最pythonic的方式来做到这一点。
