python: fix bug in .str.extract dtype

pola-rs · Jan 8, 2022 · 838f05a · 838f05a
1 parent bf6e189
commit 838f05a
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/py-polars/src/lazy/dsl.rs b/py-polars/src/lazy/dsl.rs
@@ -515,7 +515,7 @@ impl PyExpr {
         };
         self.clone()
             .inner
-            .map(function, GetOutput::from_type(DataType::Boolean))
+            .map(function, GetOutput::from_type(DataType::Utf8))
             .into()
     }
 

diff --git a/py-polars/tests/test_strings.py b/py-polars/tests/test_strings.py
@@ -0,0 +1,6 @@
+import polars as pl
+
+def test_extract_binary():
+    df = pl.DataFrame({'foo': ['aron', 'butler', 'charly', 'david']})
+    out = df.filter(pl.col('foo').str.extract('^(a)', 1) == 'a').to_series()
+    assert out[0] == "aron"