find second minimum in a row in matlab without sorting

No one knows what L, m, i1, or mini is. Why would more than 1 variable be necessary?
a loop is certainly unnecessary
applying the abs() results in minimum magnitudes which was never mentioned in the question.
Most importantly, there are two much better approaches proposed here, both of which can be adapted to apply abs().

Nitin Sapre's entire (incomplete) solution

for i1 = 1:m %treg(1:ti,i1)
    %      for col = find(L(m,:) ~= 0)
    L(L== 0) = NaN;
    [mini(i1,1),mini(i1,2)] = min(abs(L(i1,:))); %first minimum
    %                    fprintf("loop ends here")
    [mini1(i1,1),mini1(i1,2)] = min(i1,abs(L([1:mini(i1,2)-1 mini(i1,2)+1:end])));
    %its this
    [mini1(i1,1),mini1(i1,2)] = min(abs(L(i1,([1:mini(i1,2)-1 mini(i1,2)+1:end]))));

Ekaterina Sadovaya's approach is to toss the first min and then find the 2nd min (adapted below)

A = [ 3.5 2 1.6 1.456 0 1.9 2.6 ; 3.8 2.6 3.9 0 6 1.564 0  ];
A(A==0) = NaN; 
[~, minIdx] = min(abs(A),[],2)
A(sub2ind(size(A),(1:size(A,1))',minIdx)) = NaN; 
min(abs(A),[],2)  %<--- there's your answer

Guillaume's approach is to use mink which was also recommended in the comment section of Ekaterina Sadovaya's solution (adapted below).

A = [ 3.5 2 1.6 1.456 0 1.9 2.6 ; 3.8 2.6 3.9 0 6 1.564 0  ];
A(A==0) = NaN; 
minvals = mink(abs(A), 2, 2)
minvals(:, 2)  %<--- there's your answer

Nitin Sapre 2019-10-21

yes sir ur approach is very much faster but Sir thing is L is my main matrix of size mxn i1 is variable to update rows and mini is matrix to store postion and value.

since i need to store value of 2nd min tin the positon of 1st min in a row and replace all other values with first min i used this approach.

since am beginner in matlab i dont know much about this.

Any kind of help ffrom your side will be appreciate.

thank you sir

Adam Danz 2019-10-21

编辑：Adam Danz 2019-10-21

"Any kind of help ffrom your side will be appreciate"

If you have any questions about the other answers that were recommended here, please let us know. I've addapted both answers to your needs in my comment above.

Sorting may be an even better approach and it's still not clear why sorting is off the table.

An accepted answer is a sign to inexperienced users that an answer is the best solution which clearly isn't the case here. This is why you are being urged to reconsider the other options.

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Answer 2

Ekaterina Sadovaya 2019-10-18

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/485740-find-second-minimum-in-a-row-in-matlab-without-sorting#answer_396928

在 MATLAB Online 中打开

You can exclude the first minimum. So, for example for the first row it will be

A1 = A(1,:);
[first_min_value, index] = min(A1);
A1(index) = [];
second_min_value = min(A1);

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Nitin Sapre 2019-10-19

why mean value?

Nitin Sapre 2019-10-19

i got the ans in my soln only.

thanks for ur help and this is not my homework

for i1 = 1:m %treg(1:ti,i1)

% for col = find(L(m,:) ~= 0)

L(L== 0) = NaN;

[mini(i1,1),mini(i1,2)] = min(abs(L(i1,:))); %first minimum

% fprintf("loop ends here")

[mini1(i1,1),mini1(i1,2)] = min(i1,abs(L([1:mini(i1,2)-1 mini(i1,2)+1:end])));

its this

[mini1(i1,1),mini1(i1,2)] = min(abs(L(i1,([1:mini(i1,2)-1 mini(i1,2)+1:end]))));

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Answer 3

Guillaume 2019-10-19

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/485740-find-second-minimum-in-a-row-in-matlab-without-sorting#answer_397153

在 MATLAB Online 中打开

Use mink

A = [ 3.5 2 1.6 1.456 0 1.9 2.6 ; 3.8 2.6 3.9 0 6 1.564 0  ];
minvals = mink(A, 2, 2);  %first 2 miminums along dimension 2.
minvals(:, 2)  %get the 2nd one

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find second minimum in a row in matlab without sorting

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