finding the index of row

This is my data set.

y =[107.5000 108.3271 178.2391 37.0000 37.7498 177.1469 177.5000 176.8030 106.7899 36.3059 36.6464 106.2095]

I am using

index=find(y(:,1)==37.7498)

This gives me a null matrix. Why?

Answer 1

[Majid Farzaneh]

Hi. Use this:

index=find(y==37.7495)

Your result is null because you have only one row and you are searching in all rows (one row) and first column. So there is no 37.7495 in your first element.

Answer 2

[Jan]

While the solution has given by Majid Farzaneh already, remember, that comparisons with floating point values are sensitive for rounding.

See: Why is 0.3 - 0.2 ~= 0.1 (link)