Implement Series.str.find() (#382)

* Implement Series.str.find()

* Remove IntegerLiteral from check of start/end

IntegerLiteral is inherited of Integer

Author: densmirn

sdc/datatypes/hpat_pandas_stringmethods_functions.py

@@ -82,6 +82,7 @@ def hpat_pandas_stringmethods_upper_impl(self):
 
 import numba
 from numba.extending import overload_method
+from numba.types import (Integer, NoneType, Omitted, StringLiteral, UnicodeType)
 
 from sdc.datatypes.common_functions import TypeChecker
 from sdc.datatypes.hpat_pandas_stringmethods_types import StringMethodsType
@@ -187,6 +188,65 @@ def hpat_pandas_stringmethods_{methodname}_impl(self{methodparams}):
 """
 
 
+@overload_method(StringMethodsType, 'find')
+def hpat_pandas_stringmethods_find(self, sub, start=0, end=None):
+    """
+    Pandas Series method :meth:`pandas.core.strings.StringMethods.find()` implementation.
+
+    Note: Unicode type of list elements are supported only. Numpy.NaN is not supported as elements.
+
+    .. only:: developer
+
+    Test: python -m sdc.runtests -k sdc.tests.test_series.TestSeries.test_series_find
+
+    Parameters
+    ----------
+    self: :class:`pandas.core.strings.StringMethods`
+        input arg
+    sub: :obj:`str`
+        Substring being searched
+    start: :obj:`int`
+        Left edge index
+        *unsupported*
+    end: :obj:`int`
+        Right edge index
+        *unsupported*
+
+    Returns
+    -------
+    :obj:`pandas.Series`
+         returns :obj:`pandas.Series` object
+    """
+
+    ty_checker = TypeChecker('Method find().')
+    ty_checker.check(self, StringMethodsType)
+
+    if not isinstance(sub, (StringLiteral, UnicodeType)):
+        ty_checker.raise_exc(sub, 'str', 'sub')
+
+    accepted_types = (Integer, NoneType, Omitted)
+    if not isinstance(start, accepted_types) and start != 0:
+        ty_checker.raise_exc(start, 'None, int', 'start')
+
+    if not isinstance(end, accepted_types) and end is not None:
+        ty_checker.raise_exc(end, 'None, int', 'end')
+
+    def hpat_pandas_stringmethods_find_impl(self, sub, start=0, end=None):
+        if start != 0:
+            raise ValueError('Method find(). The object start\n expected: 0')
+        if end is not None:
+            raise ValueError('Method find(). The object end\n expected: None')
+
+        item_count = len(self._data)
+        result = numpy.empty(item_count, numba.types.int64)
+        for idx, item in enumerate(self._data._data):
+            result[idx] = item.find(sub)
+
+        return pandas.Series(result, self._data._index, name=self._data._name)
+
+    return hpat_pandas_stringmethods_find_impl
+
+
 @overload_method(StringMethodsType, 'isupper')
 def hpat_pandas_stringmethods_isupper(self):
     """

sdc/hiframes/pd_series_ext.py

@@ -758,7 +758,7 @@ def resolve_head(self, ary, args, kws):
     Functions which are still overloaded by HPAT compiler pipeline
 """
 
-str2str_methods_excluded = ['upper', 'isupper', 'len', 'lower',
+str2str_methods_excluded = ['upper', 'find', 'isupper', 'len', 'lower',
                             'lstrip', 'rstrip', 'strip']
 """
     Functions which are used from Numba directly by calling from StringMethodsType

sdc/tests/test_series.py

@@ -2424,6 +2424,59 @@ def test_impl(S1, S2):
                 hpat_func(S1, S2), test_impl(S1, S2),
                 err_msg='S1={}\nS2={}'.format(S1, S2))
 
+    def test_series_str_find(self):
+        def test_impl(series, sub):
+            return series.str.find(sub)
+        hpat_func = self.jit(test_impl)
+
+        data = test_global_input_data_unicode_kind4
+        subs = [''] + [s[:min(len(s) for s in data)] for s in data] + data
+        indices = [None, list(range(len(data)))[::-1], data[::-1]]
+        names = [None, 'A']
+        for index, name in product(indices, names):
+            series = pd.Series(data, index, name=name)
+            for sub in subs:
+                pd.testing.assert_series_equal(hpat_func(series, sub),
+                                               test_impl(series, sub))
+
+    def test_series_str_find_exception_unsupported_start(self):
+        def test_impl(series, sub, start):
+            return series.str.find(sub, start)
+        hpat_func = self.jit(test_impl)
+
+        series = pd.Series(test_global_input_data_unicode_kind4)
+        msg_tmpl = 'Method {}(). The object {}\n {}'
+
+        with self.assertRaises(TypingError) as raises:
+            hpat_func(series, '', '0')
+        msg = msg_tmpl.format('find', 'start', 'given: unicode_type\n '
+                                               'expected: None, int')
+        self.assertIn(msg, str(raises.exception))
+
+        with self.assertRaises(ValueError) as raises:
+            hpat_func(series, '', 1)
+        msg = msg_tmpl.format('find', 'start', 'expected: 0')
+        self.assertIn(msg, str(raises.exception))
+
+    def test_series_str_find_exception_unsupported_end(self):
+        def test_impl(series, sub, start, end):
+            return series.str.find(sub, start, end)
+        hpat_func = self.jit(test_impl)
+
+        series = pd.Series(test_global_input_data_unicode_kind4)
+        msg_tmpl = 'Method {}(). The object {}\n {}'
+
+        with self.assertRaises(TypingError) as raises:
+            hpat_func(series, '', 0, 'None')
+        msg = msg_tmpl.format('find', 'end', 'given: unicode_type\n '
+                                             'expected: None, int')
+        self.assertIn(msg, str(raises.exception))
+
+        with self.assertRaises(ValueError) as raises:
+            hpat_func(series, '', 0, 0)
+        msg = msg_tmpl.format('find', 'end', 'expected: None')
+        self.assertIn(msg, str(raises.exception))
+
     def test_series_str_len1(self):
         def test_impl(S):
             return S.str.len()