Repeat rows that start with a particular value
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Hi, I am trying to repeat a column in an array where all columns start with 1. Example, I want row 2 (1110100) to be repeated in rows where the second column contain 1. So this would apply to the first and last row.
0 1 0 0 0 0 0
1 1 1 0 1 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 1 0 0 0 0 0
which I want to look like this
1 1 1 0 1 0 0
1 1 1 0 1 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
1 1 1 0 1 0 0
采纳的回答
Image Analyst
2016-6-7
Try this to find the rows that need repeating:
m = [...
0 1 0 0 0 0 0
1 1 1 0 1 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 1 0 0 0 0 0]
rowsToRepeat = m(:, 2) == 1
We can't fully answer the question because you did not say where you want the repeated rows to go. Do you want to append them to the end? Do you want the repeated row to go right below it's original location?
5 个评论
Andre Munoz
2016-6-7
Image Analyst
2016-6-8
You should learn about repmat(). Here's one way:
m = [...
0 1 0 0 0 0 0
1 1 1 0 1 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 1 0 0 0 0 0]
[rows, columns] = size(m);
rowsToRepeat = m(:, 2) == 1
allRow2 = repmat(m(2,:), [rows, 1])
m(rowsToRepeat, :) = allRow2(rowsToRepeat,:)
Here is another way:
rowsToRepeat = m(:, 2) == 1
m(rowsToRepeat, :) = repmat(m(2,:), [sum(rowsToRepeat), 1])
Andre Munoz
2016-6-8
Andre Munoz
2016-6-8
Andre Munoz
2016-6-8
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