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Andrew Clancy
Published
Edited
Dec 15, 2020
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md`# Apache Arrow Timestamp Investigation`
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arrow = require('apache-arrow')
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md`### loading a feather file with a datetime64[ns] col, written with pandas/pyarrow 2`
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df = fetchArrow(url)
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tsSeries = df.getColumn('event_timestamp')
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md`### No timestamps here ...`
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tsSeries.get(50)
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tsSeries.toArray()
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{
const timestamps = [];
for (const ts of tsSeries) {
timestamps.push(ts);
}
return timestamps;
}
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// Fetch and instantiate an Arrow-formatted dataset
async function fetchArrow(dataUrl) {
// return arrow.Table.from(fetch(dataUrl));
const buf = await fetch(dataUrl).then(response => response.arrayBuffer());
return arrow.Table.from(new Uint8Array(buf));
}
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md`### And an Arquero test for good measure`
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import { aq, op } from '@uwdata/arquero'
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aq.fromArrow(df).view()
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