impl str.islower (#456)

* impl str.islower

* correction problem PEP*

* correction doc

* deleted 1 excess blank line

Author: Rubtsowa

examples/series/str/series_str_islower.py

@@ -0,0 +1,39 @@
+# *****************************************************************************
+# Copyright (c) 2019, Intel Corporation All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#     Redistributions of source code must retain the above copyright notice,
+#     this list of conditions and the following disclaimer.
+#
+#     Redistributions in binary form must reproduce the above copyright notice,
+#     this list of conditions and the following disclaimer in the documentation
+#     and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# *****************************************************************************
+
+import pandas as pd
+from numba import njit
+
+
+@njit
+def series_str_islower():
+    series = pd.Series(['leopard', 'Golden Eagle', 'SNAKE', ''])
+    out_series = series.str.islower()
+
+    return out_series  # Expect series of True, False, False, False
+
+
+print(series_str_islower())

sdc/datatypes/hpat_pandas_stringmethods_functions.py

@@ -1147,6 +1147,84 @@ def hpat_pandas_stringmethods_isalpha_impl(self):
     return hpat_pandas_stringmethods_isalpha_impl
 
 
+@overload_method(StringMethodsType, 'islower')
+def hpat_pandas_stringmethods_islower(self):
+    """
+        Intel Scalable Dataframe Compiler User Guide
+        ********************************************
+        Pandas API: pandas.Series.str.islower
+
+        Limitations
+        -----------
+        Series elements are expected to be Unicode strings. Elements cannot be NaN.
+
+        Examples
+        --------
+        .. literalinclude:: ../../../examples/series/str/series_str_islower.py
+           :language: python
+           :lines: 27-
+           :caption: Check if all the characters in the text are alphanumeric
+           :name: ex_series_str_islower
+
+        .. command-output:: python ./series/str/series_str_islower.py
+            :cwd: ../../../examples
+
+        .. seealso::
+            :ref:`Series.str.isalpha <pandas.Series.str.isalpha>`
+                Check whether all characters are alphabetic.
+            :ref:`Series.str.isnumeric <pandas.Series.str.isnumeric>`
+                Check whether all characters are numeric.
+            :ref:`Series.str.isalnum <pandas.Series.str.isalnum>`
+                Check whether all characters are alphanumeric.
+            :ref:`Series.str.isdigit <pandas.Series.str.isdigit>`
+                Check whether all characters are digits.
+            :ref:`Series.str.isdecimal <pandas.Series.str.isdecimal>`
+                Check whether all characters are decimal.
+            :ref:`Series.str.isspace <pandas.Series.str.isspace>`
+                Check whether all characters are whitespace.
+            :ref:`Series.str.islower <pandas.Series.str.islower>`
+                Check whether all characters are lowercase.
+            :ref:`Series.str.isupper <pandas.Series.str.isupper>`
+                Check whether all characters are uppercase.
+            :ref:`Series.str.istitle <pandas.Series.str.istitle>`
+                Check whether all characters are titlecase.
+
+        Intel Scalable Dataframe Compiler Developer Guide
+        *************************************************
+
+        Pandas Series method :meth:`pandas.core.strings.StringMethods.islower()` implementation.
+
+        Note: Unicode type of list elements are supported only. Numpy.NaN is not supported as elements.
+
+        .. only:: developer
+
+        Test: python -m sdc.runtests sdc.tests.test_series.TestSeries.test_series_islower_str
+
+        Parameters
+        ----------
+        self: :class:`pandas.core.strings.StringMethods`
+            input arg
+
+        Returns
+        -------
+        :obj:`pandas.Series`
+             returns :obj:`pandas.Series` object
+        """
+
+    ty_checker = TypeChecker('Method islower().')
+    ty_checker.check(self, StringMethodsType)
+
+    def hpat_pandas_stringmethods_islower_impl(self):
+        item_count = len(self._data)
+        result = numpy.empty(item_count, numba.types.boolean)
+        for idx, item in enumerate(self._data._data):
+            result[idx] = item.islower()
+
+        return pandas.Series(result, self._data._index, name=self._data._name)
+
+    return hpat_pandas_stringmethods_islower_impl
+
+
 # _hpat_pandas_stringmethods_autogen_methods = sorted(dir(numba.types.misc.UnicodeType.__getattribute__.__qualname__))
 _hpat_pandas_stringmethods_autogen_methods = ['upper', 'lower', 'lstrip', 'rstrip', 'strip']
 """

sdc/tests/test_series.py

@@ -238,6 +238,10 @@ def isalpha_usecase(series):
     return series.str.isalpha()
 
 
+def islower_usecase(series):
+    return series.str.islower()
+
+
 GLOBAL_VAL = 2
 
 
@@ -5524,6 +5528,17 @@ def test_series_isalpha_str(self):
             S = pd.Series(ser)
             pd.testing.assert_series_equal(cfunc(S), isalpha_usecase(S))
 
+    @skip_sdc_jit("Series.str.islower is not supported yet")
+    def test_series_islower_str(self):
+        series = [['leopard', 'Golden Eagle', 'SNAKE', ''],
+                  ['Hello world!', 'hello 123', 'mynameisPeter']
+                  ]
+
+        cfunc = self.jit(islower_usecase)
+        for ser in series:
+            S = pd.Series(ser)
+            pd.testing.assert_series_equal(cfunc(S), islower_usecase(S))
+
 
 if __name__ == "__main__":
     unittest.main()