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PrefixNamespace IRI
isaphttp://webisa.webdatacommons.org/prov/
isahttp://webisa.webdatacommons.org/
n4stackoverflow.
rdfhttp://www.w3.org/1999/02/22-rdf-syntax-ns#
provhttp://www.w3.org/ns/prov#
xsdhhttp://www.w3.org/2001/XMLSchema#
Subject Item
isa:176256408
rdf:type
prov:Entity
prov:value
You can optimize the first solution(indexof == lastindexof) just by checking the condition for all the 26 alphabets i.e. for a, b, c, d,..,z.
prov:wasQuotedFrom
n4:com
Subject Item
isap:472293403
prov:wasDerivedFrom
isa:176256408