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  1. Spark
  2. SPARK-23899 Built-in SQL Function Improvement
  3. SPARK-23939

High-order function: transform_keys(map<K1, V>, function<K1, V, K2>) → map<K2,V>

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    Details

    • Type: Sub-task
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 2.3.0
    • Fix Version/s: 3.0.0
    • Component/s: SQL
    • Labels:
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      Description

      Ref: https://prestodb.io/docs/current/functions/map.html

      Returns a map that applies function to each entry of map and transforms the keys.

      SELECT transform_keys(MAP(ARRAY[], ARRAY[]), (k, v) -> k + 1); -- {}
      SELECT transform_keys(MAP(ARRAY [1, 2, 3], ARRAY ['a', 'b', 'c']), (k, v) -> k + 1); -- {2 -> a, 3 -> b, 4 -> c}
      SELECT transform_keys(MAP(ARRAY ['a', 'b', 'c'], ARRAY [1, 2, 3]), (k, v) -> v * v); -- {1 -> 1, 4 -> 2, 9 -> 3}
      SELECT transform_keys(MAP(ARRAY ['a', 'b'], ARRAY [1, 2]), (k, v) -> k || CAST(v as VARCHAR)); -- {a1 -> 1, b2 -> 2}
      SELECT transform_keys(MAP(ARRAY [1, 2], ARRAY [1.0, 1.4]), -- {one -> 1.0, two -> 1.4}
                            (k, v) -> MAP(ARRAY[1, 2], ARRAY['one', 'two'])[k]);
      
      

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            • Assignee:
              codeatri Neha Patil
              Reporter:
              smilegator Xiao Li
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              • Created:
                Updated:
                Resolved: