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https://issues.apache.org/jira/browse/ARROW-7738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17086650#comment-17086650
]
Anders Rune Jensen commented on ARROW-7738:
-------------------------------------------
For future travelers this can be done using something like:
{code:java}
const link = '%TbiUknx1XfDdxccudfDds54hfzVNCjh2N99KXtLuyVc=.sha256'
const uLink = new TextEncoder("utf-8").encode(link);
var q2 = Array.from(
all.filter(
arrow.predicate.custom(
(idx) => {
var l = get_links(idx)
if (l.length > 0) {
var s = l.values.slice(l.valueOffsets[0],
l.valueOffsets[l.valueOffsets.length-1])
var findIndex = 0
for (var i = 0; i < s.length; ++i) {
if (s[i] == uLink[findIndex])
{
if (++findIndex == uLink.length)
return true
} else
findIndex = 0
}
return false
} else
return false
},
(batch) => {
get_links = arrow.predicate.col('links').bind(batch)
})
)
)
{code}
> [JS] Implement list contains predicate
> --------------------------------------
>
> Key: ARROW-7738
> URL: https://issues.apache.org/jira/browse/ARROW-7738
> Project: Apache Arrow
> Issue Type: Improvement
> Components: JavaScript
> Affects Versions: 0.15.1
> Reporter: Anders Rune Jensen
> Priority: Minor
>
> As far as I can see there is no way to check if a list contains a specific
> element.
> My code is as follows:
>
> {code:java}
> var all = arrow.Table.new([
> arrow.DateVector.from(dates),
> arrow.Int32Vector.from(flumeseqs),
> arrow.Utf8Vector.from(keys),
> arrow.Vector.from({ values: authors, type: new arrow.Dictionary(new
> arrow.Utf8(), new arrow.Int32()) }),
> arrow.Int32Vector.from(sequences),
> arrow.Vector.from({ values: types, type: new arrow.Dictionary(new
> arrow.Utf8(), new arrow.Int32()) }),
> arrow.Vector.from({ values: links, type: new arrow.List(listChild) }),
> ], ["date", "flumeseq", "key", "author", "sequence", "type", "links"])
> {code}
> And I want to get all the items that has a specific element in the links
> section.
> So something like:
>
> {code:java}
> var q2 = Array.from(
> all.filter(
>
> arrow.predicate.col('links').contains('%GcvjVk+NLsjOB5Vd+vceGXEOeYmHoRA6lgXVJzPuMxw=.sha256')))
> {code}
>
>
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