Splitting a range in two according to a predicate is a common
enough need. How do you translate this C++/STL idiom to D/Phobos?


vector<int> source_data;
...
vector<int> good_stuff, bad_stuff;
partition_copy(begin(source_data), end(source_data),
                inserter(good_stuff, end(good_stuff)),
                inserter(bad_stuff, end(bad_stuff)),
                is_good);


If this is not handy to implement with the current Phobos, is it
worth adding a similar function to Phobos?

Thank you,
bye,
bearophile

On 5/5/13 7:22 AM, bearophile wrote:
> Splitting a range in two according to a predicate is a common
> enough need. How do you translate this C++/STL idiom to D/Phobos?
>
>
> vector<int> source_data;
> ...
> vector<int> good_stuff, bad_stuff;
> partition_copy(begin(source_data), end(source_data),
> inserter(good_stuff, end(good_stuff)),
> inserter(bad_stuff, end(bad_stuff)),
> is_good);
>
>
> If this is not handy to implement with the current Phobos, is it
> worth adding a similar function to Phobos?
>
> Thank you,
> bye,
> bearophile

Yah, I've been thinking of adding a new category of functions that generate multiple ranges and conversely merge multiple ranges into one.

A possibility here is to define segregate!pred(range) that takes a predicate and a range and returns a tuple of two ranges (for true and false values of the predicate). The two ranges can be consumed at different rates etc.

That won't work with input ranges though.


Andrei