assignment vs std::swap and merging and keeping duplicates in seperate object
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rubenvb
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Published on 2011-03-06T16:07:24Z
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2011/03/06
16:10 UTC
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Say I have two std::set<std::string>
s. The first one, old_options
, needs to be merged with additional options, contained in new_options
. I can't just use std::merge
(well, I do, but not only that) because I also check for doubles and warn the user about this accordingly. To this effect, I have
void merge_options( set<string> &old_options, const set<string> &new_options )
{
// find duplicates and create merged_options, a stringset containing the merged options
// handle duplicated the way I want to
// ...
old_options = merged_options;
}
Is it better to use
std::swap( merged_options, old_options );
or the assignment I have?
Is there a better way to filter duplicates and return the merged
set
than consecutive calls tostd::set_intersection
andstd::set_union
to detect dupes and merge theset
s? I know it's slower than one traversal and doing both at once, but these sets are small (performance is not critical) and I trust the Standard more than I trust myself.
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