Equality of a numeric list using a string

I have a set of values fwhm that I then remove valyes lower than Y20. However, I use this in many places and sometimes want values > Y20

T=fwhm(fwhm>Y20);

Is there a way to pass the string for the equality, where in the case above I could pass either '>Y20' or '<Y20'?

Thanks

Answer 1

[Walter Roberson]

If Y20 is known at the time you decide whether you want > or <, then define a function:

selY20 = @(Var) Var(Var>Y20);

or

selY20 = @(Var) Var(Var<Y20);

depending on which one you want. Then your code would have

T = selY20(fwhm);

If you do not know Y20 at the time you make the decision, then at the time of the decision define a function

selY = @(Var, Y) Var(Var<Y);

or

selY = @(Var, Y) Var(Var>Y);

and code

T = selY(fwhm, Y20);

Or if you want to be more hard-core,

selY = @lt;

or

selY = @gt;

and code

T = fwhm(selY(fwhm, Y20));

A < B is the same internally as lt(A,B) and A > B is the same internally as gt(A,B)

Answer 2

[Guillaume]

I'd recommend you use function handles rather than strings:

comparisons = {@gt, @lt}; %gt is the function name of >, lt is the function name of <

selectedcomparison = 1; %1 is <, 2 is >
T = fwhm(comparisons{selectedcomparison}(fwhm, Y20)) %note that the brackets after {...} is a function call

edit: if you really want to use strings:

comparisons = {'<', '>'};
selectedcomparison = 1; %1 is <, 2 is >
compfn = str2func((comparisons{selectedcomparison});
T = fwhm(compfn(fwhm, Y20))

Answer 3

[Jason]

Thankyou Walter and Guillaume.