On 12/06/2013 01:36 AM, Bernhard Voelker wrote: > On 12/06/2013 02:26 AM, Bernhard Voelker wrote: >> On 12/06/2013 02:13 AM, Pádraig Brady wrote: >>> I suppose we could make -r require that -n is specified, >>> but I'm not sure. >> >> Regarding this in the above context - no, because then you would >> have to specify -n1 when "picking 1 random item". Saving the user >> from typing -n1 seems to be _the_ reason for assuming n=1. > > OTOH there may be cases where you don't know the number of items > beforehand, but you want shuf to output that number of random items > from the input regardless of repetitions: > > $ gen_data | shuf -r > > Shuf will know the number of elements and may easily pick that > number incl. repetitions. > > If you want to pick just one, you know it and it's easy to say -n1, > but it's not that easy in the above case.
But with random selection would there ever be a link between input and output cardinality? I can't think of a case that there would be. Pádraig.
