Programmer Guide/Command Reference/EVAL/select: Difference between revisions

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:;<var>x</var>: condition vector; must be a vector!
:;<var>x</var>: condition vector; must be a vector!
:;<var>t</var>: threshold
:;<var>t</var>: threshold
:;<var>yl</var>: result if <code>''x''[''i''] <= ''t''{[''i'']}</code>
:;<var>yl</var>: result if <code>''x''[''i''] &le; ''t''{[''i'']}</code>
:;<var>yh</var>: result if <code>''x''[''i''] > ''t''{[''i'']}</code>
:;<var>yh</var>: result if <code>''x''[''i''] > ''t''{[''i'']}</code>
: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''

Revision as of 11:47, 21 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]} if x[i] ≤ t{[i]} and
r[i] = yh{[i]} if x[i] > t{[i]}
The result r has the same length as x.
See also
vsubc, limit, limitlow, limithigh

Example:

#a := eval vv(1,2,3,4,5,4,3,2,1)
#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 }

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