Counting consecutive negative numbers in an array

BN
2020 11 24
1 个回答
回答已采纳
更新时间：2020 11 24
13 次查看（30 天）

0 个投票

Hello, I need to find how many times consecutive negative numbers are in the array. For example:
v = [11 2 3 -1 -2 1 -1 -1 -3 1 3 -1];
The answer must be: 3
Thank you

请先登录，再回答此问题。

 采纳的回答

Bruno Luong
Bruno Luong 2020-11-24
编辑：Bruno Luong 2020-11-24

1 个投票

length(strfind([false v<0],[0 1]))
or
sum(diff([false v<0])==1)

3 个评论
显示 1更早的评论 隐藏 1更早的评论

BN
BN 2020-11-24
Thank you...
I don't know why the answer is 2! I need 3. I think it doesn't count last -1 values. any idea?
Thank you so much again
Bruno Luong
Bruno Luong 2020-11-24
编辑：Bruno Luong 2020-11-24
How do you get 2?
>> v= [11 2 3 -1 -2 1 -1 -1 -3 1 3 -1]
v =
11 2 3 -1 -2 1 -1 -1 -3 1 3 -1
>> length(strfind([false v<0],[0 1]))
ans =
3
>> sum(diff([false v<0])==1)
ans =
3
BN
BN 2020-11-24
Thank you so much. I forgot to use the clear command then try the code. After that, your code works very well.
Thank you it is really helpful for me

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Logical 的更多信息

产品

版本

R2020a

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by