larray-project
diff --git a/‎doc/source/api.rst
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diff --git a/‎doc/source/changes/version_0_33.rst.inc
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diff --git a/‎larray/core/axis.py
Lines changed: 45 additions & 0 deletions b/‎larray/core/axis.py
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diff --git a/‎larray/tests/test_axis.py
Lines changed: 9 additions & 1 deletion b/‎larray/tests/test_axis.py
Lines changed: 9 additions & 1 deletion
@@ -71,6 +71,7 @@ Modifying/Selecting
    Axis.align
    Axis.split
    Axis.ignore_labels
+   Axis.astype
 
 Testing
 -------
 
@@ -54,6 +54,7 @@ Miscellaneous improvements
 * scalar objects (i.e of type int, float, bool, string, date, time or datetime) belonging to a session
   are now also saved and loaded when using the HDF5 or pickle format (closes :issue:`842`).
 
+* implemented :py:obj:`Axis.astype()` method (closes :issue:`880`).
 
 Fixes
 ^^^^^
 
@@ -4,6 +4,8 @@
 import warnings
 from itertools import product
 
+from typing import Union
+
 import numpy as np
 import pandas as pd
 
@@ -234,6 +236,49 @@ def by(self, length, step=None, template=None):
         """
         return self[:].by(length, step, template)
 
+    def astype(self, dtype: Union[str, np.dtype], casting: str = 'unsafe') -> 'Axis':
+        """
+        Cast labels to a specified type.
+
+        Parameters
+        ----------
+        dtype: str or dtype
+            Typecode or data-type to which the labels are cast.
+
+        casting: str, optional
+            Controls what kind of data casting may occur. Defaults to `unsafe`.
+
+                * `no` means the data types should not be cast at all.
+                * `equiv` means only byte-order changes are allowed.
+                * `safe` means only casts which can preserve values are allowed.
+                * `same_kind` means only safe casts or casts within a kind, like float64 to float32, are allowed.
+                * `unsafe` means any data conversions may be done.
+
+        Returns
+        -------
+        Axis
+            Axis with labels converted to the new type.
+
+        Examples
+        --------
+        >>> from larray import ndtest
+        >>> arr = ndtest('time=2015..2020')
+        >>> arr = arr.with_total()
+        >>> arr
+        time  2015  2016  2017  2018  2019  2020  total
+                 0     1     2     3     4     5     15
+        >>> arr = arr.drop('total')
+        >>> time = arr.time
+        >>> time
+        Axis([2015, 2016, 2017, 2018, 2019, 2020], 'time')
+        >>> time.dtype
+        dtype('O')
+        >>> time = time.astype(int)
+        >>> time.dtype                      # doctest: +SKIP
+        dtype('int64')
+        """
+        return Axis(labels=self.labels.astype(dtype=dtype, casting=casting), name=self.name)
+
     def extend(self, labels):
         r"""
         Append new labels to an axis or increase its length in case of wildcard axis.
 
@@ -3,7 +3,7 @@
 import numpy as np
 
 from larray.tests.common import assert_array_equal, assert_nparray_equal, needs_pytables
-from larray import Axis, LGroup, IGroup, read_hdf, X
+from larray import Axis, LGroup, IGroup, read_hdf, X, ndtest
 from larray.core.axis import AxisReference
 
 
@@ -94,6 +94,14 @@ def test_translate():
     assert a.index('a1 >> A1') == 1
 
 
+def test_astype():
+    arr = ndtest(Axis('time=2015..2020,total')).drop('total')
+    time = arr.time
+    assert time.dtype.kind == 'U'
+    time = time.astype(int)
+    assert time.dtype.kind == 'i'
+
+
 def test_getitem_lgroup_keys():
     def group_equal(g1, g2):
         return g1.key == g2.key and g1.name == g2.name and g1.axis is g2.axis