Programmer Guide/Command Reference/EVAL/vvget: Difference between revisions
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[[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | [[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | ||
Revision as of 14:44, 4 April 2011
Extract elements from a vector.
- Usage
vvget(x {, o {, d {,n }}})- x
- the source vector, lx=nrow(x) must be greater/equal 1
- o
- the first element to be extracted, 0 <= o < lx (default=0)
- d
- the index increment (default=1)
- n
- the number of elements to extract, n>0 (default=lx)
- Result
- A numerical object r (scalar or vector) with n elements
ri = xo+i*d; with i=0..n-1
- Note: For all i, the source index o+i*d must be in the range 0 to lx-1, otherwise the function failes.
- See also
- vv, vvset, vvcat, vmcol, vmrow, vsubn, vsubc
Example:
#a := eval vv(1,2,4,8,16,32)
#b := eval vvget($#a, 0, 2, 3)
// -> #b = { 1 , 4 , 16 }
#c := eval vvget($#a, 5, -1, 4)
// -> #c = { 32, 16, 8, 4 }
