Question

Given two collections:

srcCollection := #('Lorem' 'ipsum' 'dolor' 'sit' 'amet,' 'consectetur' 'adipisicing' 'elit,' 'sed' 'do' 'eiusmod' 'tempor' 'incididunt' 'ut' 'labore' 'et' 'dolore' 'magna' 'aliqua.' 'Ut' 'enim' 'ad' 'minim' 'veniam,' 'quis' 'nostrud' 'exercitation' 'ullamco' 'laboris' 'nisi' 'ut' 'aliquip' 'ex' 'ea' 'commodo' 'consequat.' 'Duis' 'aute' 'irure' 'dolor' 'in' 'reprehenderit' 'in' 'voluptate' 'velit' 'esse' 'cillum' 'dolore' 'eu' 'fugiat' 'nulla' 'pariatur.' 'Excepteur' 'sint' 'occaecat' 'cupidatat' 'non' 'proident,' 'sunt' 'in' 'culpa' 'qui' 'officia' 'deserunt' 'mollit' 'anim' 'id' 'est' 'laborum').      
objCollection := #('Lorem' 'numquam' 'eius' 'modi' 'tempora' 'incidunt' 'ut' 'labore' 'et' 'dolore' 'magnam' 'aliquam' 'ipsum' 'dolor' 'ex' 'ea' 'commodo' 'consequat.' 'Duis' 'aute' 'irure' 'dolor' 'in' 'reprehenderit' 'in' 'voluptate' 'velit' 'esse' 'cillum' 'dolore' 'eu' 'fugiat' 'nulla' 'pariatur.' 'Excepteur' 'sint' 'occaecat' 'cupidatat' 'non' 'proident,' 'sunt' 'in' 'culpa' 'qui' 'officia' 'deserunt' 'mollit' 'anim' 'id' 'est' 'laborum' 'Sed' 'ut' 'perspiciatis' 'unde' 'omnis' 'iste' 'natus' 'error' 'sit' 'voluptatem' 'accusantium' 'doloremque' 'laudantium,' 'totam' 'rem' 'aperiam,' 'eaque' 'ipsa' 'quae' 'ab' 'illo' 'inventore' 'veritatis' 'et' 'quasi' 'architecto' 'sit' 'amet,' 'consectetur' 'adipisicing' 'elit,' 'sed' 'do' 'eiusmod' 'tempor' 'incididunt' 'ut' 'labore' 'et' 'dolore' 'magna' 'aliqua.' 'Ut' 'enim' 'ad' 'minim' 'veniam,' 'quis' 'nostrud' 'exercitation' 'ullamco' 'laboris' 'nisi' 'ut' 'aliquip' 'beatae' 'vitae' 'dicta' 'sunt' 'explicabo.' 'Nemo' 'enim' 'ipsam' 'voluptatem' 'quia' 'voluptas' 'sit' 'aspernatur' 'aut' 'odit' 'aut' 'fugit,' 'sed' 'quia' 'consequuntur' 'magni' 'dolores' 'eos' 'qui' 'ratione' 'voluptatem' 'sequi' 'nesciunt.' 'Neque' 'porro' 'quisquam' 'est,' 'qui' 'dolorem' 'ipsum' 'quia' 'dolor' 'sit' 'amet,' 'consectetur,' 'adipisci' 'velit,' 'sed' 'quia' 'non' 'quaerat' 'voluptatem.' 'Ut' 'enim' 'ad' 'minima' 'veniam,' 'quis' 'nostrum' 'exercitationem' 'ullam' 'corporis' 'suscipit' 'laboriosam,' 'nisi' 'ut' 'aliquid' 'ex' 'ea' 'commodi' 'consequatur?' 'Quis' 'autem' 'vel' 'eum' 'iure' 'reprehenderit' 'qui' 'in' 'ea' 'voluptate' 'velit' 'esse' 'quam' 'nihil' 'molestiae' 'consequatur,' 'vel' 'illum' 'qui' 'dolorem' 'eum' 'fugiat' 'quo' 'voluptas' 'nulla' 'pariatur?').

where objCollection is guaranteed to contain all elements in srcCollection. Note: In my application objCollection are actually complex objects containing these strings as identifiers with no duplicates.

I’ve been measuring and trying to optimize selecting all the objects in objCollection that are also in srcCollection. The times below are in milliseconds using [ 1000 timesRepeat: [ ... ] ] timeToRun in Pharo 1.2 with Stack VM and Windows XP with 2Gb of memory. These are my attempts:

objCollection intersection: srcCollection
7537
7507

objCollection select: [: str | srcCollection includes: str ]
7471
7507

srcCollection collect: [: str | objCollection detect: [: obj | obj = str ] ]
4227
4323

Is there a faster way?

Answer 1

If you can afford to add asSet to the two collections, you might do faster. I went from 1480 to 197 ms.