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NAME
modify - modify a list or matrix by changing the values of its elements
SYNOPSIS
modify(A, fname)
TYPES
A lvalue with list, matrix or object value
fname string, the name of a user-defined function
return null value if successful, otherwise an error value
DESCRIPTION
The value of each element of A is replaced by the value at that
value of the user-defined function with name fname. Thus,
modify(A, "f") has the effect of
for (i = 0; i < size(A); i++) A[[i]] = f(A[[i]]);
An error value is returned if A is not of acceptable type, if A has
no-change protection, or if there is no user-defined function with
name fname. The assignments are executed even if the protection
status of some elements A[[i]] would normally prevent the
assignment of f(A[[i]]) to A[[i]]. The modified elements retain
whatever kinds of protection they had as well as gaining any
other kinds of protection in the values returned by the function.
To obtain a modified copy of A without changing values in A,
one may use
Amod = A; modify(A, fname)
or more simply
modify(Amod = A, fname).
EXAMPLE
; define f(x) = x^2
; A = list(2,4,6)
; modify(A, "f")
; print A
list (3 elements, 3 nonzero):
[[0]] = 4
[[1]] = 16
[[3]] = 36
LIMITS
none
LINK LIBRARY
none
SEE ALSO
makelist
## Copyright (C) 1999,2021 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1995/07/10 02:09:31
## File existed as early as: 1995
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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