Improve casting of strings to datetime

.github/workflows/pythonpackage.yml

@@ -19,7 +19,7 @@ defaults:
 jobs:
   main:
     env:
-      CACHE_NUMBER_COMPILE: 5
+      CACHE_NUMBER_COMPILE: 6
       MAMBA_ROOT_PREFIX: /dev/shm/mambaroot
     runs-on: ${{ matrix.os }}
     strategy:

ci/actions/windll/action.yml

@@ -5,9 +5,10 @@ runs:
   steps:
     - shell: bash
       run: |
-        ls /c/Program\ Files\ \(x86\)/Microsoft\ Visual\ Studio/2019/Enterprise/VC/Redist/
-        ls /c/Program\ Files\ \(x86\)/Microsoft\ Visual\ Studio/2019/Enterprise/VC/Redist/MSVC/
-        cp /c/Program\ Files\ \(x86\)/Microsoft\ Visual\ Studio/2019/Enterprise/VC/Redist/MSVC/14.29.30133/x64/Microsoft.VC142.CRT/vcruntime140_1.dll packages/vaex-core/vaex/
+        ls /c/Program\ Files/Microsoft\ Visual\ Studio/2022
+        ls /c/Program\ Files/Microsoft\ Visual\ Studio/2022/Enterprise/VC/Redist/
+        ls /c/Program\ Files/Microsoft\ Visual\ Studio/2022/Enterprise/VC/Redist/MSVC/
+        cp /c/Program\ Files/Microsoft\ Visual\ Studio/2022/Enterprise/VC/Redist/MSVC/14.29.30133/x64/Microsoft.VC142.CRT/vcruntime140_1.dll packages/vaex-core/vaex/
         mkdir packages/vaex-core/vendor/pcre
         cd packages/vaex-core/vendor/pcre
         curl https://anaconda.org/conda-forge/pcre/8.44/download/win-64/pcre-8.44-h6538335_0.tar.bz2 -Lo pcre.tar.bz2

ci/conda-env.yml

@@ -11,7 +11,7 @@ dependencies:
 - cachetools
 - catboost
 - diskcache
-- fsspec
+- fsspec<2022.2.0
 - gcsfs
 - geopandas
 - graphviz

packages/vaex-core/vaex/column.py

@@ -264,7 +264,10 @@ def _fingerprint(self):
     @property
     def nbytes(self):
         # consistent with arrow
-        return self.indices.nbytes
+        if int(pa.__version__.split(".")[0]) >= 7:
+            return self.indices.nbytes + self.dictionary.nbytes
+        else:
+            return self.indices.nbytes
 
     @property
     def dtype(self):

packages/vaex-core/vaex/functions.py

@@ -2513,8 +2513,13 @@ def _astype(x, dtype):
                     units = dtype[len('datetime64')+1:-1]
                 else:
                     units = 'ns'
-                dtype = pa.timestamp(units)
-
+                if vaex.dtype_of(x) == str and units in ['m', 'h', 'D', 'W', 'M', 'Y']:
+                    # it's a slower path, but it works
+                    # using pc.strptime seems to offset by a day orso?
+                    x = np.array(x, dtype=dtype)
+                    return x.astype(dtype)
+                else:
+                    dtype = pa.timestamp(units)
             else:  # parse dtype
                 if len(dtype) > len('timedelta64'):
                     units = dtype[len('timedelta64')+1:-1]

tests/astype_test.py

@@ -53,3 +53,15 @@ def test_astype_timedelta(df_factory):
     df = df_factory(x=x)
     df['x_expected'] = df.x.astype('timedelta64[s]')
     assert x_result.tolist() == df.x_expected.tolist()
+
+
+def test_astype_str_to_datetime(df_factory):
+    x = ['2020-05', '2021-10', '2022-01']
+    y = ['2020', '2021', '2022']
+    x_validation = np.array(x, dtype='datetime64[M]')
+    y_validation = np.array(y, dtype='datetime64[Y]')
+    df = df_factory(x=x, y=y)
+    df['x_dt'] = df.x.astype('datetime64[M]')
+    df['y_dt'] = df.y.astype('datetime64[Y]')
+    assert all(df.x_dt.values == x_validation)
+    assert all(df.y_dt.values == y_validation)