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'How to' Matrix

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Hello kity
Hello kity 2012-12-12
关闭： MATLAB Answer Bot 2021-8-20
I have an array with 0 s and 1s.
Example a colomn, 0 ,0 ,0 ,0 , 1.
Now the 1 is on the 5th row, I want to raise that to the first row.
So, in my code i want all the ones to go 4 steps up...
sounds easy, but how :) ?
  5 个评论
显示 3更早的评论
Hello kity
Hello kity 2012-12-12
I meant shifting, shifting the 1 on the 4th row to the 1st.
Jan
Jan 2012-12-12
Thanks for the clarification, Student. And what happens on the right margin? Is the result shorter, filled with zeros or ones or with the value of the last element?

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回答（4 个）

Walter Roberson
Walter Roberson 2012-12-12
编辑：Walter Roberson 2012-12-12
Have you considered circshift() up by 4 rows?
Azzi Abdelmalek
Azzi Abdelmalek 2012-12-12
A=[0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 1]
for k=5:length(A)
if A(k)
b=A(k-4:k-1);
A(k-4)=1
A(k-4+1:k)=b
end
end
  2 个评论
Hello kity
Hello kity 2012-12-12
Would you comment this code step by step, I dont get how you do this...
thank you
Azzi Abdelmalek
Azzi Abdelmalek 2012-12-12
A=[0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 1]
for k=5:length(A)
if A(k) % If A(k) is equal to 1
b=A(k-4:k-1); % store value from k-4 to k-1 in b
A(k-4)=1 % replace value at k-1 by 1
A(k-4+1:k)=b % shift value stored in b
end
end
Andrei Bobrov
Andrei Bobrov 2012-12-12
编辑：Andrei Bobrov 2012-12-12
other way:
a - your vector - row (eg: [0 0 0 0 1])
n = numel(a);
out = a(hankel(1:n,[n,1:n-1]));
or
out = hankel(a,circshift(a,[0 1]));
  1 个评论
Hello kity
Hello kity 2012-12-12
thank you,
afterwards i use Q=out(:,5);
Jan
Jan 2012-12-12
编辑：Jan 2012-12-12
Some ideas:
x = [0, 0, 0, 0, 1];
index = find(x, 1, 'first');
y1 = x(index:end);
y2 = [x(index:end), zeros(1, index - 1)];
y3 = [x(index:end), ones(1, index - 1)];
y4 = [x(index:end), repmat(x(end), 1, index - 1)];
y5 = [x(index:end), x(1:index - 1)];

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