how to find a float number

I have a data (saved as double), as in the attache file. I need to find for example if a certain float number (for ex. -0.334) exist or no.

find(y7==-0.3340)

but because the nubers actully exist as -0.3440099999999 or sth like that, I can't find.

I have tried to change the format, but it did'nt solve the problem.

Any suggestions??

Answer 1

[per isakson]

find( abs( y7 -(-0.3340) ) < tol )

You choose tol. See eps - Floating-point relative accuracy

[Suzuki]

brilliant, thanks...

Answer 2

[Walter Roberson]

[is_there, idx] = ismembertol(-0.3340, y7)  %options allow you to control tolerances
y7(idx)

Also,

[~, idx] = min(abs(y7(:) - (-0.3340)));
y7(idx)

will show you the y7 that is closest to -0.3340, even if it is not very close. Whereas the ismembertol() will only return results if the value is within tolerance

[Suzuki]

that solve the problem, thanks alot.