more tests

xarray/core/accessor_str.py

@@ -78,14 +78,10 @@ def get(self, i, default=None):
         items : array of objects
         '''
         if default is None:
-            default = ''
+            default = self._obj.dtype.type('')
 
-        def f(x):
-            n = len(x)
-            if n <= i or i < -n:
-                return default
-            return x[i]
-        return self._apply(f)
+        obj = slice(i, i + 1)
+        return self._apply(lambda x: x[obj])
 
     def slice(self, start=None, stop=None, step=None):
         '''
@@ -130,12 +126,14 @@ def slice_replace(self, start=None, stop=None, repl=''):
         -------
         replaced : same type as values
         '''
+        repl = self._obj.dtype.type(repl)
+
         def f(x):
-            if x[start:stop] == '':
+            if len(x[start:stop]) == 0:
                 local_stop = start
             else:
                 local_stop = stop
-            y = ''
+            y = self._obj.dtype.type('')
             if start is not None:
                 y += x[:start]
             y += repl
@@ -314,6 +312,7 @@ def count(self, pat, flags=0):
         -------
         counts : array of int
         '''
+        pat = self._obj.dtype.type(pat)
         regex = re.compile(pat, flags=flags)
         f = lambda x: len(regex.findall(x))
         return self._apply(f, dtype=int)
@@ -333,6 +332,7 @@ def startswith(self, pat):
             An array of booleans indicating whether the given pattern matches
             the start of each string element.
         '''
+        pat = self._obj.dtype.type(pat)
         f = lambda x: x.startswith(pat)
         return self._apply(f, dtype=bool)
 
@@ -351,6 +351,7 @@ def endswith(self, pat):
             A Series of booleans indicating whether the given pattern matches
             the end of each string element.
         '''
+        pat = self._obj.dtype.type(pat)
         f = lambda x: x.endswith(pat)
         return self._apply(f, dtype=bool)
 
@@ -374,7 +375,7 @@ def pad(self, width, side='left', fillchar=' '):
             Array with a minimum number of char in each element.
         '''
         width = int(width)
-        fillchar = str(fillchar)
+        fillchar = self._obj.dtype.type(fillchar)
         if len(fillchar) != 1:
             raise TypeError('fillchar must be a character, not str')
 
@@ -491,6 +492,7 @@ def contains(self, pat, case=True, flags=0, regex=True):
             given pattern is contained within the string of each element
             of the array.
         '''
+        pat = self._obj.dtype.type(pat)
         if regex:
             if not case:
                 flags |= re.IGNORECASE
@@ -530,6 +532,7 @@ def match(self, pat, case=True, flags=0):
         if not case:
             flags |= re.IGNORECASE
 
+        pat = self._obj.dtype.type(pat)
         regex = re.compile(pat, flags=flags)
         f = lambda x: bool(regex.match(x))
         return self._apply(f, dtype=bool)
@@ -554,6 +557,9 @@ def strip(self, to_strip=None, side='both'):
         -------
         stripped : same type as values
         '''
+        if to_strip is not None:
+            to_strip = self._obj.dtype.type(to_strip)
+
         if side == 'both':
             f = lambda x: x.strip(to_strip)
         elif side == 'left':
@@ -703,7 +709,8 @@ def find(self, sub, start=0, end=None, side='left'):
         -------
         found : array of integer values
         '''
-        sub = str(sub)
+        sub = self._obj.dtype.type(sub)
+
         if side == 'left':
             method = 'find'
         elif side == 'right':
@@ -761,7 +768,7 @@ def index(self, sub, start=0, end=None, side='left'):
         -------
         found : array of integer values
         '''
-        sub = str(sub)
+        sub = self._obj.dtype.type(sub)
 
         if side == 'left':
             method = 'index'
@@ -837,6 +844,12 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=True):
         if not (_is_str_like(repl) or callable(repl)):
             raise TypeError("repl must be a string or callable")
 
+        if _is_str_like(pat):
+            pat = self._obj.dtype.type(pat)
+
+        if _is_str_like(repl):
+            repl = self._obj.dtype.type(repl)
+
         is_compiled_re = isinstance(pat, type(re.compile('')))
         if regex:
             if is_compiled_re:
@@ -906,4 +919,4 @@ def encode(self, encoding, errors='strict'):
         else:
             encoder = codecs.getencoder(encoding)
             f = lambda x: encoder(x, errors)[0]
-        return self._apply(f, dtype=np.string_)
+        return self._apply(f, dtype=np.bytes_)