Created
June 17, 2021 20:39
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Balanced fold
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| import org.apache.spark.sql.Column | |
| def treeFold( | |
| columns: List[Column], | |
| initialValue: Column, | |
| op: (Column, Column) => Column | |
| ): Column = { | |
| if (columns.isEmpty) { | |
| initialValue | |
| } else if (columns.length == 1) { | |
| columns.head | |
| } else { | |
| val (left, right) = columns.splitAt(columns.length / 2) | |
| op( | |
| treeFold(left, initialValue, op), | |
| treeFold(right, initialValue, op) | |
| ) | |
| } | |
| } |
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