Delete rows only if there are at least a repeated zero value in the previous or next row of the same column

I need your help fellows. I want to remove all rows which contain at least a repeated zero value in the previous/next row of the second column. Look at the next example:

Input=

124.2  8.6  7.2  -4.8
131.1  1.8  1.4  -1.2
131.9  0.0  0.0  0.0
123.0  0.0  0.0  0.0
2323.0  3.0  3.0  3.0
2323.0  0.0  0.0  0.0
221.0  3.1  4.0  5.6
57.0  1.0  231.0  122.0
987.0  0.0  0.0  0.0
4454.0  0.0  0.0  0.0
3.0  0.0  0.0  0.0
434.0  0.0  0.0  0.0

Output=

124.2  8.6  7.2  -4.8
131.1  1.8  1.4  -1.2
2323.0  3.0  3.0  3.0
2323.0  0.0  0.0  0.0
221.0  3.1  4.0  5.6
57.0  1.0  231.0  122.0

Only it was maintened the sixth row of the original table (input) due to there was not a zero in the previous/next row of the same column (second column).

Thanks in advance for your help!

[Walter Roberson]

Your line

131.1  1.8  1.4  -1.2

is followed by two lines in which the second column is 0, so if the "repeated 0" refers to the second column, that line should be removed according to your criteria.

Your line

123.0  0.0  0.0  0.0

is followed by a line that does not have 0 in the second column of the next row, so according to your rules it must be kept.

Your line

434.0  0.0  0.0  0.0

has no following lines, and so does not have a 0 in the next row, so according to your rules it must be kept.

[Miguel L]

Walter thanks for your comments. Let me clarify the issue: It is necessary remove rows looking for zeros at the previous/next row of the second column. At the end, I am looking for the result enlisted at the output:

Output=

124.2  8.6  7.2  -4.8
131.1  1.8  1.4  -1.2
2323.0  3.0  3.0  3.0
2323.0  0.0  0.0  0.0
221.0  3.1  4.0  5.6
57.0  1.0  231.0  122.0

[Walter Roberson]

Your line

131.1  1.8  1.4  -1.2

is followed by a line that has 0 in its second column, so according to your rules it should be removed.

Perhaps you want the rule to be that if there is a set of rows in which there are at least two rows in a row with 0 in the second column, that the entire block with zeros there should be removed ?

Answer 1

[Walter Roberson]

Assuming that the rule is that if there is a set of rows in which there are at least two rows in a row with 0 in the second column, that the entire block with zeros there should be removed, then:

mask1 = input(:,2) ~= 0;
mask2 = mask1(1:end-1) | mask1(2:end);
keep_row = [true;mask2] & [mask2;true];
output = input(keep_row, :);

[Miguel L]

Thanks Walter it works perfectly!

[Andrei Bobrov]

+1