2to3: Apply unicode fixer.

The unicode fixer strips the u from u'hi' and converts the unicode type
to str. The first won't work for Python 2 and instead we replace the u
prefix with the sixu function borrowed from the six compatibility
package. That function calls the unicode constructor with the
'unicode_escape' encoder so that the many tests using escaped unicode
characters like u'\u0900' will be handled correctly. That makes the
sixu function a bit different from the asunicode function currently in
numpy.compat and also provides a target that can be converted back to
the u prefix when support for Python 3.2 is dropped. Python 3.3
reintroduced the u prefix for compatibility.

The unicode fixer also replaces 'unicode' with 'str' as 'unicode' is no
longer a builtin in Python 3. For code compatibility, 'unicode' is
defined either as 'str' or 'unicode' in numpy.compat so that checks like

    if isinstance(x, unicode):
        ...

will work properly for all python versions.

Closes #3089.

1 files changed, 10 insertions, 5 deletions

diff --git a/numpy/lib/npyio.py b/numpy/lib/npyio.py
index 2154acdce..6a353762b 100644
--- a/numpy/lib/npyio.py
+++ b/numpy/lib/npyio.py
@@ -14,12 +14,17 @@ from operator import itemgetter
 from ._datasource import DataSource
 from ._compiled_base import packbits, unpackbits
 
-from ._iotools import LineSplitter, NameValidator, StringConverter, \
-                     ConverterError, ConverterLockError, ConversionWarning, \
-                     _is_string_like, has_nested_fields, flatten_dtype, \
-                     easy_dtype, _bytes_to_name
+from ._iotools import (
+        LineSplitter, NameValidator, StringConverter,
+        ConverterError, ConverterLockError, ConversionWarning,
+        _is_string_like, has_nested_fields, flatten_dtype,
+        easy_dtype, _bytes_to_name
+        )
+
+from numpy.compat import (
+        asbytes, asstr, asbytes_nested, bytes, basestring, unicode
+        )
 
-from numpy.compat import asbytes, asstr, asbytes_nested, bytes, basestring
 from io import BytesIO
 
 if sys.version_info[0] >= 3: