Programmer Guide/Command Reference/EVAL/select: Difference between revisions
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:Note: ''t'', ''yl'' and ''yh'' must be numbers or vectors with the same length as ''x'' | :Note: ''t'', ''yl'' and ''yh'' must be numbers or vectors with the same length as ''x'' | ||
;Result: A vector ''r'' with ... | ;Result: A vector ''r'' with ... | ||
::<code>''r''[i] = ''yl''{[''i'']}</code> if ''x''[''i]'' <= ''t''{[''i'']}</code> and | ::<code>''r''[i] = ''yl''{[''i'']}</code> if <code>''x''[''i]'' <= ''t''{[''i'']}</code> and | ||
::<code>''r''[i] = ''yh''{[''i'']}</code> if ''x''[''i]'' > ''t''{[''i'']}</code> | ::<code>''r''[i] = ''yh''{[''i'']}</code> if <code>''x''[''i]'' > ''t''{[''i'']}</code> | ||
:The result r has the same length as ''x''. | :The result r has the same length as ''x''. | ||
Revision as of 12:23, 6 April 2011
Conditional merge of selected elements of two vectors and/or scalars.
- Usage
select(x, t, yl, yh)- x
- condition vector; must be a vector!
- t
- threshold
- yl
- result if
x[i] <= t{[i]} - yh
- result if
x[i] > t{[i]}
- Note: t, yl and yh must be numbers or vectors with the same length as x
- Result
- A vector r with ...
r[i] = yl{[i]}ifx[i] <= t{[i]}andr[i] = yh{[i]}ifx[i] > t{[i]}
- The result r has the same length as x.
Example:
#a := eval vv(1,2,3,4,5,4,3,2,1)
0 1 2 3 4 5 6 7 8
#b := eval fill(9,0,1)
#c := eval select($#a,3,0,$#a)
// -> $#c = { 0 , 0 , 0 , 4 , 5 , 4 , 0 , 0 , 0 }
#d := eval select($#a, $#b , $#b , $#a)
// -> $#d = { 1 , 2 , 3 , 4 , 5 , 5 , 6 , 7 , 8 }
#e := eval select($#b%2, 0, $#b, -1)
// -> $#d = { 0 , -1 , 2 , -1 , 4 , -1 , 6 , -1 , 8 }
