Matrix/
make_selection.pro
Convert an array of selected values to an index
array that identifies the selected values in a list or data array.
make_selection
tools
result = make_selection(names, selnames, ONLY_VALID=ONLY_VALID, REQUIRED=REQUIRED, QUIET=QUIET)
Return value
A (long) array with indexes to reference the selected values
in the NAMES array.
Parameters
names
in
required
A list or array of values to choose from
selnames
in
required
A list of selected values
Keywords
ONLY_VALID
Return only indexes of found values. Values not
found are skipped. Default is to return 1 index value for
each SELNAME, which is -1 if SELNAME is not contained in
NAMES. If ONLY_VALID is set, the -1 values will be deleted,
and a value of -1 indicates that no SELNAME has been found
at all.
REQUIRED
Normally, MAKE_SELECTION will return indexes for
all values that are found, simply ignoring the selected
values that are not in the NAMES array (although an error
message is displayed). Set this keyword to return with
-1 as soon as a selected value is not found.
QUIET
Suppress printing of the error message if a
selected value is not found (the error condition will
still be set).
Examples
names = [ 'Alfred','Anton','Peter','John','Mary']
index = MAKE_SELECTION(names,['Peter','Mary'])
print,index
; prints 2 4
vals = indgen(20)
index = MAKE_SELECTION(vals,[9,-5,8,7,7,8,9])
print,index
; prints 9 -1 8 7 7 8 9
index = MAKE_SELECTION(vals,[9,-5,8,7,7,8,9],/ONLY_VALID)
print,index
; prints 9 8 7 7 8 9
index = MAKE_SELECTION(vals,[9,-5,8,7,7,8,9],/REQUIRED)
print,index
; prints -1
Version history
Version
$Id: make_selection.pro 262 2007-08-21 14:19:32Z pinsard $
History
mgs, 28 Aug 1998: VERSION 1.00
mgs, 29 Aug 1998: - changed behavior and added ONLY_VALID keyword
Copyright (C) 1998, Martin Schultz, Harvard University
This software is provided as is without any warranty
whatsoever. It may be freely used, copied or distributed
for non-commercial purposes. This copyright notice must be
kept with any copy of this software. If this software shall
be used commercially or sold as part of a larger package,
please contact the author to arrange payment.
Bugs and comments should be directed to mgs@io.harvard.edu
with subject "IDL routine make_selection"
Known issues
Restrictions
If the NAMES array contains multiple entries of the same value,
only the index to the first entry will be returned.
A selection can contain multiple instances of the same value.
The index array will contain one entry per selected item
(See example below)
Produced by IDLdoc 2.0.