Programmer Guide/Command Reference/EVAL/vsubc: Difference between revisions
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The result is a scalar or a vector with the selected elements from <var>x1</var> (or <var>x2</var> - see <var>x2</var> for details). | The result is a scalar or a vector with the selected elements from <var>x1</var> (or <var>x2</var> - see <var>x2</var> for details). | ||
{{DISPLAYTITLE:{{SUBPAGENAME}}}} | |||
Extract rows from a vector or matrix. | |||
;Usage: '''<code>vsubc(<var>x</var> , 0 , <var>vmin</var> {, <var>y</var> }})</code>''' | |||
::'''<code>vsubc(<var>x</var> , 1 , <var>vmax</var> {, <var>y</var> }})</code>''' | |||
::'''<code>vsubc(<var>x</var> , 2 , <var>vmin</var>, <var>vmax</var> {, <var>y</var> }})</code>''' | |||
::'''<code>vsubc(<var>x</var> , 3 , <var>vmin</var>, <var>vmax</var> {, <var>y</var> }})</code>''' | |||
:;<var>x</var>: condition vector (and source vector if argument ''y'' is not supplied); must be a vector! | |||
:;<var>vmin</var>: lower boundary; must be a scalar or a vector with the same length as ''x'' | |||
:;<var>vmax</var>: upper boundary; must be a scalar or a vector with the same length as ''x'' | |||
:;<var>y</var>: optional source data; must be a vector or matrix with the same number of rows as ''x'' | |||
;Result: A numerical object with <code>nrow(''x'')</code> columns and ''n'' rows, consisting of the rows ''o'' to ''o''+''n''-1 of the argument ''x''. | |||
;Description: The 2nd argument ''c'' (a number in the range 0..3) defines the condition used for the selection of the source rows. | |||
;* 2nd argument is '''0''' | |||
;See also: [[Programmer_Guide/Command_Reference/EVAL/vsubc|vsubc]], [[Programmer_Guide/Command_Reference/EVAL/select|select]], | |||
[[Programmer_Guide/Command_Reference/EVAL/vvset|vv]] | |||
Example: | |||
<pre> | |||
#a := eval vv(1,2,3,4,5) | |||
#b := eval vmcol($#a, vv(5,4,3,2,1)) | |||
#c := vsubn($#a,3) | |||
// -> vector: $#c = { 4 , 5 } | |||
#d := eval vsubn($#b, 1 , 3) | |||
// -> matrix: $#d[*,0] = { 2 , 3 , 4 }, $#d[*,1] = { 4 , 3 , 2 } | |||
#e := eval vsubn($#a, 2, 1) | |||
// -> scalar: $#e = 2, this is equivalent to $#a[2] | |||
#f := eval vsubn($#b, 2, 1) | |||
// -> vector (!!): $#f = { 3 , 3 }, this is equivalent to $#b[2,*] | |||
</pre> | |||
[[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | |||
Revision as of 10:45, 6 April 2011
Contents
vsubc
Conditional extraction of elements from the vector x.
Usage:
vsubc(x1,c,s1,x2)
vsubc(x1,c,s1,s2,x2)
Parameters:
- x1
- The input vector.
- c
- The condition. The following values are supported:
0- select all x[i] where x[i] < s1
- 1 - select all x[i] where x[i] > s1
2- select all x[i] where s1 < x[i] < s2
- s1
- A real number. See c for details.
- s2
- A real number (only used if c
==2). See c for details.
- x2
- x2 is optional. If specified, the elements in x2 are extracted based on the selected values in x1. x2 must be a vector with exactly the same number of rows as x1.
Result:
The result is a scalar or a vector with the selected elements from x1 (or x2 - see x2 for details).
Extract rows from a vector or matrix.
- Usage
vsubc(x , 0 , vmin {, y }})vsubc(x , 1 , vmax {, y }})vsubc(x , 2 , vmin, vmax {, y }})vsubc(x , 3 , vmin, vmax {, y }})- x
- condition vector (and source vector if argument y is not supplied); must be a vector!
- vmin
- lower boundary; must be a scalar or a vector with the same length as x
- vmax
- upper boundary; must be a scalar or a vector with the same length as x
- y
- optional source data; must be a vector or matrix with the same number of rows as x
- Result
- A numerical object with
nrow(x)columns and n rows, consisting of the rows o to o+n-1 of the argument x. - Description
- The 2nd argument c (a number in the range 0..3) defines the condition used for the selection of the source rows.
- 2nd argument is 0
Example:
#a := eval vv(1,2,3,4,5)
#b := eval vmcol($#a, vv(5,4,3,2,1))
#c := vsubn($#a,3)
// -> vector: $#c = { 4 , 5 }
#d := eval vsubn($#b, 1 , 3)
// -> matrix: $#d[*,0] = { 2 , 3 , 4 }, $#d[*,1] = { 4 , 3 , 2 }
#e := eval vsubn($#a, 2, 1)
// -> scalar: $#e = 2, this is equivalent to $#a[2]
#f := eval vsubn($#b, 2, 1)
// -> vector (!!): $#f = { 3 , 3 }, this is equivalent to $#b[2,*]
