Count the number of times a value appears in a row and save the row number

I wanted to sort points in an array based on how many times a number less than or equal to 1.5 appears in the row. I want to save the row index number of those that have 3 or more occurences less than or equal to the target value of 1.5. I have placed the array below. If you have any ideas on how to do this that would be great. Thanks for your time.

A = [NaN	1.00000000000000	1.00000000000000	1.99994495218295	1.40991828545270	1.98465118243128	2.97995391814023	1.41286932041226	1.44150019470391	2.30703739193881
1.00000000000000	NaN	1.41618367600370	0.999999999999996	1.00000000000000	2.11349467948903	1.98589244648483	1.00000000000000	1.73544845449717	1.98611502337309
1.00000000000000	1.41618367600370	NaN	2.24512987514306	2.20570040562793	0.999999999999996	3.22884118121504	1.75480404405606	1	3.15259384660772
1.99994495218295	0.999999999999996	2.24512987514306	NaN	1.40867173007472	2.65578172203034	1.00000000000000	1.41514975278174	2.44463958996392	2.12446752335984
1.40991828545270	1.00000000000000	2.20570040562793	1.40867173007472	NaN	3.01897607767301	2.11695260794737	1.62219494319153	2.57847672580517	1.00000000000000
1.98465118243128	2.11349467948903	0.999999999999996	2.65578172203034	3.01897607767301	NaN	3.52998354037453	2.38833466800397	1.41223022448087	3.96751962825988
2.97995391814023	1.98589244648483	3.22884118121504	1.00000000000000	2.11695260794737	3.52998354037453	NaN	2.21498386821498	3.35954605769311	2.49207458085697
1.41286932041226	1.00000000000000	1.75480404405606	1.41514975278174	1.62219494319153	2.38833466800397	2.21498386821498	NaN	1.44673037867744	2.53341581840774
1.44150019470391	1.73544845449717	1	2.44463958996392	2.57847672580517	1.41223022448087	3.35954605769311	1.44673037867744	NaN	3.56150161869124
2.30703739193881	1.98611502337309	3.15259384660772	2.12446752335984	1.00000000000000	3.96751962825988	2.49207458085697	2.53341581840774	3.56150161869124	NaN];

Answer 1

[Star Strider]

Try this:

rowsum = sum((A <= 1.5), 2);
result = find(rowsum >= 3)

producing:

result =
     1
     2
     3
     4
     5
     8
     9

Those could be combined into one line:

result = find(sum((A <= 1.5), 2) >= 3)

I kept them separate for clarity.

[James Peach]

Thank you! I just have one question, when I tried to keep the row numbers of the rows that don't meet the criteria, reversing the less than and greater than signs didnt work. How would I do the opposite of this operation?

[Star Strider]

As always, my pleasure!

It depends on what ‘don’t meet the criteria’ means, since there are two criteria.

Every row has more than 3 numbers greater than 1.5, so:

result = find(sum((A > 1.5), 2) >= 3)

returns all the rows.

This:

result = find(sum((A > 1.5), 2) < 3)

returns an empty array because the second criteriion was not met.

This:

result = find(sum((A <= 1.5), 2) < 3)

returns:

result =
     6
     7
    10

that may be what you want, since it is the complement of the vector returned by the original test.

If you want a different result than any of these. please go into a bit of detail in describing it.

[James Peach]

Sorry Im just seeing this, but I meant the 3rd case you showed which is the complement of the original vector. Thank you again!

[Star Strider]

That’s what I thought, although I wanted to explain the other options.

As always, my pleasure!