how to use function "find" over matrices

Suppose x = rand(1e5,1e5);
I want to find the lowest number in each column of x without using for loop.
Is it possible?

 Accepted Answer

"find the first value in each column which lis ess than 0.25 but greater than 0.2."
>> x = rand(13,7)
x =
0.833676 0.654529 0.869031 0.922756 0.586565 0.278136 0.595271
0.335144 0.936490 0.552751 0.676447 0.924786 0.813253 0.388776
0.171351 0.992074 0.426227 0.814150 0.599205 0.378885 0.470132
0.368957 0.162066 0.044178 0.911514 0.431260 0.111011 0.348894
0.787866 0.150796 0.783209 0.406310 0.116503 0.232302 0.350849
0.676606 0.782741 0.251472 0.223849 0.872576 0.665249 0.287961
0.176415 0.750830 0.958001 0.274026 0.107420 0.716966 0.612980
0.030644 0.103396 0.297286 0.256401 0.902245 0.486087 0.812681
0.563573 0.414845 0.615615 0.335131 0.589437 0.396942 0.780523
0.994748 0.314337 0.721215 0.946815 0.446822 0.252527 0.593235
0.438298 0.516228 0.978322 0.183097 0.011558 0.731435 0.948024
0.496606 0.172242 0.224708 0.339960 0.425773 0.730056 0.809002
0.234744 0.195880 0.086287 0.702632 0.708232 0.489843 0.558111
>> y = x>0.2 & x<0.25;
>> [row,col] = find(y & cumsum(y,1)==1)
row =
13
12
6
5
col =
1
3
4
6

More Answers (1)

min(x);

3 Comments

Let me to clarify the question.
Suppose it is aimed to find the first value in each column which lis ess than 0.25 but greater than 0.2.
How can I do that?
x = rand(1e4);
a = x.*(x>.2&x<.25);
b=arrayfun(@(y)a(find(a(:,y),1),y),1:size(a,2));
Thank you David. It works well. But the method suggested by Stephen is a little easier.

Sign in to comment.

Categories

Tags

Community Treasure Hunt

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

Start Hunting!