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https://issues.apache.org/jira/browse/TINKERPOP-2314?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stephen Mallette updated TINKERPOP-2314:
----------------------------------------
Description:
This bit of Gremlin demonstrates both problems for uses of {{by(String)}}:
{code}
gremlin> g.V().valueMap().project('x').by('name')
java.util.LinkedHashMap cannot be cast to
org.apache.tinkerpop.gremlin.structure.Element
Type ':help' or ':h' for help.
Display stack trace? [yN]n
{code}
First, users typically expect this to work because they figure they are just
grabbing a keys value from a {{Map}} and then get the difficult to understand
message which doesn't tell you how to resolve. As a side note, the way to
resolve is with:
{code}
gremlin> g.V().valueMap().project('x').by(select('name'))
==>[x:[marko]]
==>[x:[stephen]]
==>[x:[matthias]]
==>[x:[daniel]]
==>[x:[gremlin]]
==>[x:[tinkergraph]]
{code}
was:
This bit of Gremlin demonstrates both problems for uses of {{by(String)}}:
{code}
gremlin> g.V().values('age').project('x').by('name')
java.lang.Integer cannot be cast to
org.apache.tinkerpop.gremlin.structure.Element
Type ':help' or ':h' for help.
Display stack trace? [yN]n
{code}
First, users typically expect this to work because they figure they are just
grabbing a keys value from a {{Map}} and then get the difficult to understand
message which doesn't tell you how to resolve. As a side note, the way to
resolve is with:
{code}
gremlin> g.V().valueMap().project('x').by(select('name'))
==>[x:[marko]]
==>[x:[stephen]]
==>[x:[matthias]]
==>[x:[daniel]]
==>[x:[gremlin]]
==>[x:[tinkergraph]]
{code}
> Employ by(String) for Map when possible and improve errors around incorrect
> types
> ---------------------------------------------------------------------------------
>
> Key: TINKERPOP-2314
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2314
> Project: TinkerPop
> Issue Type: Improvement
> Components: process
> Affects Versions: 3.3.9
> Reporter: Stephen Mallette
> Assignee: Stephen Mallette
> Priority: Major
>
> This bit of Gremlin demonstrates both problems for uses of {{by(String)}}:
> {code}
> gremlin> g.V().valueMap().project('x').by('name')
> java.util.LinkedHashMap cannot be cast to
> org.apache.tinkerpop.gremlin.structure.Element
> Type ':help' or ':h' for help.
> Display stack trace? [yN]n
> {code}
> First, users typically expect this to work because they figure they are just
> grabbing a keys value from a {{Map}} and then get the difficult to understand
> message which doesn't tell you how to resolve. As a side note, the way to
> resolve is with:
> {code}
> gremlin> g.V().valueMap().project('x').by(select('name'))
> ==>[x:[marko]]
> ==>[x:[stephen]]
> ==>[x:[matthias]]
> ==>[x:[daniel]]
> ==>[x:[gremlin]]
> ==>[x:[tinkergraph]]
> {code}
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