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https://issues.apache.org/jira/browse/ARROW-12099?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17555329#comment-17555329
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Nick Crews commented on ARROW-12099:
------------------------------------
Small tweak to Guido's implementation (thank you for this!): If the table only
has the one ListArray or MapArray column, then it crashes.
This handles that case:
{code:python}
import pyarrow as paimport pyarrow.compute as pc
def explode_table(table, column): null_filled = pc.fill_null(table[column],
[None]) flattened = pc.list_flatten(null_filled) other_columns =
list(table.schema.names) other_columns.remove(column) if
len(other_columns) == 0: return pa.table({column: flattened}) else:
indices = pc.list_parent_indices(null_filled) result =
table.select(other_columns).take(indices) result = result.append_column(
pa.field(column, table.schema.field(column).type.value_type),
flattened, ) return result {code}
> [Python] Explode array column
> -----------------------------
>
> Key: ARROW-12099
> URL: https://issues.apache.org/jira/browse/ARROW-12099
> Project: Apache Arrow
> Issue Type: New Feature
> Components: Python
> Reporter: Malthe Borch
> Priority: Major
>
> In Apache Spark,
> [explode|https://spark.apache.org/docs/latest/api/sql/index.html#explode]
> separates the elements of an array column (or expression) into multiple row.
> Note that each explode works at the top-level only (not recursively).
> This would also work with the existing
> [flatten|https://arrow.apache.org/docs/python/generated/pyarrow.Table.html#pyarrow.Table.flatten]
> method to allow fully unnesting a
> [pyarrow.StructArray|https://arrow.apache.org/docs/python/generated/pyarrow.StructArray.html#pyarrow-structarray].
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