Programmer Guide/Command Reference/EVAL/vsubc: Difference between revisions
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::;''c''=2: select all rows ''i'' where <code>''vmin'' < '' ''x''[''i''] < ''vmax''</code> | ::;''c''=2: select all rows ''i'' where <code>''vmin'' < '' ''x''[''i''] < ''vmax''</code> | ||
::;''c''=3: select all rows ''i'' where <code>''x''[i] <= ''vmin'' or ''x''[''i''] >= ''vmax''</code> | ::;''c''=3: select all rows ''i'' where <code>''x''[i] <= ''vmin'' or ''x''[''i''] >= ''vmax''</code> | ||
:If | :If a boundary ''vmin''/''vmax'' is a vector, the i-th element of the vectors ''x'' and ''vmin''/''vmax'' are compared, otherwise the element ''x''[''i''] is compared with the number ''vmin''/''vmax''. | ||
;See also: [[Programmer_Guide/Command_Reference/EVAL/vsubn|vsubn]], [[Programmer_Guide/Command_Reference/EVAL/select|select]], [[Programmer_Guide/Command_Reference/EVAL/vvset|vv]] | ;See also: [[Programmer_Guide/Command_Reference/EVAL/vsubn|vsubn]], [[Programmer_Guide/Command_Reference/EVAL/select|select]], [[Programmer_Guide/Command_Reference/EVAL/vvset|vv]] | ||
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#a := eval vv(1,2,3,4,5) | #a := eval vv(1,2,3,4,5) | ||
#b := eval vmcol($#a, vv(5,4,3,2,1)) | #b := eval vmcol($#a, vv(5,4,3,2,1)) | ||
#c := | #c := vsubc($#a,0,3) | ||
// -> vector: $#c = { | // -> vector: $#c = { 1 , 2 } | ||
#d := eval | #d := eval vsubc($#a,2,0,5,$#b) | ||
// -> matrix: $#d[*,0] = { 2 , 3 , 4 }, $#d[*,1] = { 4 , 3 , 2 } | // -> matrix: $#d[*,0] = { 2 , 3 , 4 }, $#d[*,1] = { 4 , 3 , 2 } | ||
</pre> | </pre> | ||
[[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | [[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | ||
Revision as of 10:01, 6 April 2011
Extract rows from a vector or matrix.
- Usage
vsubc(x , 0 , vmin {, y }})vsubc(x , 1 , vmax {, y }})vsubc(x , 2 , vmin, vmax {, y }})vsubc(x , 3 , vmin, vmax {, y }})- x
- condition vector (and source vector if argument y is not supplied); must be a vector!
- vmin
- lower boundary; must be a scalar or a vector with the same length as x
- vmax
- upper boundary; must be a scalar or a vector with the same length as x
- y
- optional source data; must be a vector or matrix with the same number of rows as x
- Result
- A numerical object consisting of all selected rows of the source y (or x if y is not supplied). The 2nd argument c must be a number in the range 0 to 3 and defines the condition used for the selection of the source rows.
- c=0
- select all rows i where
x[i] < vmin - c=1
- select all rows i where
x[i] > vmax - c=2
- select all rows i where
vmin < x[i] < vmax - c=3
- select all rows i where
x[i] <= vmin or x[i] >= vmax
- If a boundary vmin/vmax is a vector, the i-th element of the vectors x and vmin/vmax are compared, otherwise the element x[i] is compared with the number vmin/vmax.
Example:
#a := eval vv(1,2,3,4,5)
#b := eval vmcol($#a, vv(5,4,3,2,1))
#c := vsubc($#a,0,3)
// -> vector: $#c = { 1 , 2 }
#d := eval vsubc($#a,2,0,5,$#b)
// -> matrix: $#d[*,0] = { 2 , 3 , 4 }, $#d[*,1] = { 4 , 3 , 2 }
