fix[rust]: parse date when day is omitted (#4495)

pola-rs · Aug 19, 2022 · 3496e33 · 3496e33
1 parent edd0a1d
commit 3496e33
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/polars/polars-time/src/chunkedarray/utf8/strptime.rs b/polars/polars-time/src/chunkedarray/utf8/strptime.rs
@@ -37,7 +37,9 @@ pub(super) unsafe fn parse(val: &[u8], fmt: &[u8], fmt_len: u16) -> Option<Naive
     }
     let mut year: i32 = 0;
     let mut month: u32 = 0;
-    let mut day: u32 = 0;
+    // minimal day is always 1
+    // otherwise chrono may panic.
+    let mut day: u32 = 1;
     let mut hour: u32 = 0;
     let mut min: u32 = 0;
     let mut sec: u32 = 0;

diff --git a/py-polars/tests/test_datelike.py b/py-polars/tests/test_datelike.py
@@ -1293,3 +1293,13 @@ def test_from_dict_tu_consistency() -> None:
     from_dicts = pl.from_dicts([{"dt": dt}])
 
     assert from_dict.dtypes == from_dicts.dtypes
+
+
+def test_date_parse_omit_day() -> None:
+    df = pl.DataFrame({"month": ["2022-01"]})
+    assert df.select(pl.col("month").str.strptime(pl.Date, fmt="%Y-%m"))[0, 0] == date(
+        2022, 1, 1
+    )
+    assert df.select(pl.col("month").str.strptime(pl.Datetime, fmt="%Y-%m"))[
+        0, 0
+    ] == datetime(2022, 1, 1)