How to Remove Specific Rows in a Multi-Column Array Based on One Column's Values

Hello,

I am trying to remove specific rows in an array based on the values in the second column, but when it removes those rows, it also removes the first column.

What I have:

data = 
    1       0.002
    2       0.304
    3       0.220
    .         .
    .         .
    1207    0.120
    1208    0.043

    % the first column of data is 1:1:1208;    

And what I want is for all rows where the second column value is <0.1 (for example) to be removed resulting in:

 data =
    2        0.304
    3        0.220
    1207     0.120 

But what I am getting is:

 data =
    0.304
    0.220
    0.120

so, I'm not able to see the column 1 value that should correspond with the remaining column 2 values.

Thank you!

Answer 1

[Voss]

data = [1:10; 0.3*rand(1,10)].'

data = 10x2

1.0000 0.0852 2.0000 0.0717 3.0000 0.2240 4.0000 0.1382 5.0000 0.0334 6.0000 0.2094 7.0000 0.2247 8.0000 0.2036 9.0000 0.1893 10.0000 0.0435

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idx = data(:,2) < 0.1;

data(idx,:) = []

data = 6x2

3.0000 0.2240 4.0000 0.1382 6.0000 0.2094 7.0000 0.2247 8.0000 0.2036 9.0000 0.1893

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The removal of the rows could also effectively be done by

data = data(~idx,:)

I don't have your code, so I can't know what you did differently, but it seems like you did

data = data(~idx,2)

[AJ]

Thank you so much, this is perfect. I was doing

data = data(~idx,2)

[Voss]

You're welcome! Any questions, let me know. Otherwise, please "Accept" this answer. Thanks!