Function Repository Resource:

MapSelectCounted

Map a function over selected elements of a list, also passing in a running count of such elements

Contributed by: Michael Sollami

ResourceFunction["MapSelectCounted"][f,list,test]

returns a list of f[x_i,j] where j is a running total incremented when test[x_i] is True.

ResourceFunction["MapSelectCounted"][f,list]

returns a list of f[x_i,i] for all elements x_iin list.

Details and Options

Oftentimes you only need the first part of the second slot of MapIndexed

Map while keeping the count:

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MapSelectCounted over a list conditionally:

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Oftentimes you only need the first part of the second slot of MapIndexed

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MapSelectCounted only works at the first level, use MapIndexed to specify deeper levels than the first:

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