how to check negative values are there or not in a matrix????

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suchismita
suchismita 2014-6-11
评论： Dyuman Joshi 2023-12-25
i have a matrix a=[0.2 0.1 -0.1 0 0.9], now i want to check whether there is any negative value if yes then those element i want to make zero.
plz plz help me....
a<0 makes all greater than as 1 and other 0. but i want to make only negative values zero and other as same as they are.
  2 个评论
Dyuman Joshi
Dyuman Joshi 2023-12-25
Ran in:
An approach to show off (lol) -
a=[0.2 0.1 -0.1 0 0.9]
a = 1×5
0.2000 0.1000 -0.1000 0 0.9000
max(a, 0)
ans = 1×5
0.2000 0.1000 0 0 0.9000

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采纳的回答

Mischa Kim
Mischa Kim 2014-6-11
suchismita, use
a(a<0) = 0;
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juveria fatima
juveria fatima 2018-9-24
@ misha kim after making the negative integer to zero in matrix i want to get back to the a as originally with negative integers ,how do i do it?
KEYUR BORAD
KEYUR BORAD 2021-2-25
Thanks @Mischa Kim this syntax helped me to find if a vector contains both neg and pos value or not!!

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更多回答（2 个）

Thomas Richner
Thomas Richner 2018-9-9
If you want to know if a matrix contains any negatives (but not to replace them) the use
contains_negative = any(a<0); % returns true or false
Anirban Naskar
Anirban Naskar 2014-6-11
编辑：Anirban Naskar 2014-6-11
Hi Suchismita,
You can use something like the following:
[m n]=size(a);
for i=1:m
for j=1:n
if a(i,j)<0
disp('contains negative element');
a(i,j)=0;
end
end
end
  2 个评论
juveria fatima
juveria fatima 2018-9-24
@ Anirban nasker you are converting the negative number in matrix to positive perfectly fine
but in my case i have i have to first convert negative to postive and again i have to get back to original 'a matrix' can any help in writing the reverse function for it

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