fix(polars): use double explode -> implode hack to flatten

ibis-project · Sep 19, 2024 · eb5f674 · eb5f674
1 parent d91c3b2
commit eb5f674
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/ibis/backends/polars/compiler.py b/ibis/backends/polars/compiler.py
@@ -1021,7 +1021,11 @@ def array_flatten(op, **kw):
         .then(None)
         .when(result.list.len() == 0)
         .then([])
-        .otherwise(result.flatten())
+        # polars doesn't have an efficient API (yet?) for removing one level of
+        # nesting from an array so we use elementwise evaluation
+        #
+        # https://github.com/ibis-project/ibis/issues/10135
+        .otherwise(result.list.eval(pl.element().flatten()))
     )