Thank you--the example was very helpful. Here's what I wanted to do (and a possibly inelegant formulation of a solution):
perldl> p $a=sequence(5)
[0 1 2 3 4]
perldl> p $b=pdl(1,4,9,9,16)
[1 4 9 9 16]

**** To get the index of values in $a that can be found anywhere in $b
+: 

perldl> $d=which(maximum (($a==$b->dummy)->xchg(0,1))!=0)

perldl> p $d
[1 4]

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In reply to Re^4: matching pdl elements by Blue_eyed_son
in thread matching pdl elements by Anonymous Monk

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