BUG: handle length-0 objects in Series.to_string, GH #488

Author: wesm

pandas/core/series.py

@@ -471,6 +471,9 @@ def to_string(self, buf=None, na_rep='NaN', float_format=None, nanRep=None,
 
     def _get_repr(self, name=False, print_header=False, length=True,
                   na_rep='NaN', float_format=None):
+        if len(self) == 0:
+            return ''
+
         vals = self.values
         index = self.index
 

pandas/src/tseries.pyx

@@ -22,33 +22,6 @@ cdef inline int int_min(int a, int b): return a if a <= b else b
 
 ctypedef unsigned char UChar
 
-cdef int is_contiguous(ndarray arr):
-    return np.PyArray_CHKFLAGS(arr, np.NPY_C_CONTIGUOUS)
-
-cdef int _contiguous_check(ndarray arr):
-    if not is_contiguous(arr):
-        raise ValueError('Tried to use data field on non-contiguous array!')
-
-cdef int16_t *get_int16_ptr(ndarray arr):
-    _contiguous_check(arr)
-
-    return <int16_t *> arr.data
-
-cdef int32_t *get_int32_ptr(ndarray arr):
-    _contiguous_check(arr)
-
-    return <int32_t *> arr.data
-
-cdef int64_t *get_int64_ptr(ndarray arr):
-    _contiguous_check(arr)
-
-    return <int64_t *> arr.data
-
-cdef double_t *get_double_ptr(ndarray arr):
-    _contiguous_check(arr)
-
-    return <double_t *> arr.data
-
 cimport util
 
 cdef extern from "math.h":

pandas/src/util.pxd

@@ -43,3 +43,6 @@ cdef inline set_value_at(ndarray arr, object loc, object value):
         raise IndexError('index out of bounds')
 
     assign_value_1d(arr, i, value)
+
+cdef inline int is_contiguous(ndarray arr):
+    return cnp.PyArray_CHKFLAGS(arr, cnp.NPY_C_CONTIGUOUS)

pandas/tests/test_series.py

@@ -539,6 +539,13 @@ def test_to_string(self):
         expected = [format(x) for x in self.ts]
         self.assertEqual(result, expected)
 
+        # empty string
+        result = self.ts[:0].to_string()
+        self.assertEqual(result, '')
+
+        result = self.ts[:0].to_string(length=0)
+        self.assertEqual(result, '')
+
     def test_iter(self):
         for i, val in enumerate(self.series):
             self.assertEqual(val, self.series[i])