2015-01-16 17:57 GMT+01:00 Jim Nasby <jim.na...@bluetreble.com>: > On 1/16/15 3:39 AM, Pavel Stehule wrote: > >> I am proposing a simple function, that returns a position of element in >> array. >> > > Yes please! > > FUNCTION array_position(anyarray, anyelement) RETURNS int >> > > That won't work on a multi-dimensional array. Ideally it needs to accept a > slice or an element and return the specifier for the slice. >
It is question, what is a result - probably, there can be a multidimensional variant, where result will be a array array_position([1,2,3],2) --> 2 array_position([[1,2],[2,3],[3,4]], [2,3]) --> 2 /* 2nd parameter should to have N-1 dimension of first parameter */ array_position_md([1,2,3],2) --> [2] array_position_md([[1,2],[2,3],[3,4]], 2) --> [2,1] another question is how to solve more than one occurrence on one value - probably two sets of functions - first returns first occurrence of value, second returns set of occurrence > > This wouldn't be so bad if we had an easier way to extract subsets of an > array, but even that is really ugly because whatever you extract keeps the > original number of dimensions. > > Implementation is simple (plpgsql code) >> > > This would actually be written in C though, yes? Otherwise it's not really > any better than just doing an extension... > Sure, I expect a C implementation Pavel > -- > Jim Nasby, Data Architect, Blue Treble Consulting > Data in Trouble? Get it in Treble! http://BlueTreble.com >
