MAINT: Remove asbytes where a b prefix would suffice

Since we only need to support python 2, we can remove any case where we just
pass a single string literal and use the b prefix instead.

What we can't do is transform asbytes("tests %d" % num), because %-formatting
fails on bytes in python 3.x < 3.5.

6 files changed, 70 insertions, 71 deletions

diff --git a/numpy/lib/_iotools.py b/numpy/lib/_iotools.py
index 312a9f02a..304bba3d3 100644
--- a/numpy/lib/_iotools.py
+++ b/numpy/lib/_iotools.py
@@ -44,7 +44,7 @@ def _is_bytes_like(obj):
     Check whether obj behaves like a bytes object.
     """
     try:
-        obj + asbytes('')
+        obj + b''
     except (TypeError, ValueError):
         return False
     return True
@@ -189,7 +189,7 @@ class LineSplitter(object):
         return lambda input: [_.strip() for _ in method(input)]
     #
 
-    def __init__(self, delimiter=None, comments=asbytes('#'), autostrip=True):
+    def __init__(self, delimiter=None, comments=b'#', autostrip=True):
         self.comments = comments
         # Delimiter is a character
         if isinstance(delimiter, unicode):
@@ -218,7 +218,7 @@ class LineSplitter(object):
     def _delimited_splitter(self, line):
         if self.comments is not None:
             line = line.split(self.comments)[0]
-        line = line.strip(asbytes(" \r\n"))
+        line = line.strip(b" \r\n")
         if not line:
             return []
         return line.split(self.delimiter)
@@ -227,7 +227,7 @@ class LineSplitter(object):
     def _fixedwidth_splitter(self, line):
         if self.comments is not None:
             line = line.split(self.comments)[0]
-        line = line.strip(asbytes("\r\n"))
+        line = line.strip(b"\r\n")
         if not line:
             return []
         fixed = self.delimiter
@@ -434,9 +434,9 @@ def str2bool(value):
 
     """
     value = value.upper()
-    if value == asbytes('TRUE'):
+    if value == b'TRUE':
         return True
-    elif value == asbytes('FALSE'):
+    elif value == b'FALSE':
         return False
     else:
         raise ValueError("Invalid boolean")
@@ -529,7 +529,7 @@ class StringConverter(object):
     _mapper.extend([(nx.floating, float, nx.nan),
                     (complex, _bytes_to_complex, nx.nan + 0j),
                     (nx.longdouble, nx.longdouble, nx.nan),
-                    (nx.string_, bytes, asbytes('???'))])
+                    (nx.string_, bytes, b'???')])
 
     (_defaulttype, _defaultfunc, _defaultfill) = zip(*_mapper)
 
@@ -631,7 +631,7 @@ class StringConverter(object):
                 # None
                 if default is None:
                     try:
-                        default = self.func(asbytes('0'))
+                        default = self.func(b'0')
                     except ValueError:
                         default = None
                 dtype = self._getdtype(default)
@@ -676,11 +676,11 @@ class StringConverter(object):
                     self.func = lambda x: int(float(x))
         # Store the list of strings corresponding to missing values.
         if missing_values is None:
-            self.missing_values = set([asbytes('')])
+            self.missing_values = set([b''])
         else:
             if isinstance(missing_values, bytes):
-                missing_values = missing_values.split(asbytes(","))
-            self.missing_values = set(list(missing_values) + [asbytes('')])
+                missing_values = missing_values.split(b",")
+            self.missing_values = set(list(missing_values) + [b''])
         #
         self._callingfunction = self._strict_call
         self.type = self._dtypeortype(dtype)
@@ -801,7 +801,7 @@ class StringConverter(object):
             self.iterupgrade(value)
 
     def update(self, func, default=None, testing_value=None,
-               missing_values=asbytes(''), locked=False):
+               missing_values=b'', locked=False):
         """
         Set StringConverter attributes directly.
 
@@ -838,7 +838,7 @@ class StringConverter(object):
             self.type = self._dtypeortype(self._getdtype(default))
         else:
             try:
-                tester = func(testing_value or asbytes('1'))
+                tester = func(testing_value or b'1')
             except (TypeError, ValueError):
                 tester = None
             self.type = self._dtypeortype(self._getdtype(tester))
diff --git a/numpy/lib/format.py b/numpy/lib/format.py
index 633aee675..14dec01d5 100644
--- a/numpy/lib/format.py
+++ b/numpy/lib/format.py
@@ -161,7 +161,7 @@ if sys.version_info[0] >= 3:
 else:
     import cPickle as pickle
 
-MAGIC_PREFIX = asbytes('\x93NUMPY')
+MAGIC_PREFIX = b'\x93NUMPY'
 MAGIC_LEN = len(MAGIC_PREFIX) + 2
 BUFFER_SIZE = 2**18  # size of buffer for reading npz files in bytes
 
diff --git a/numpy/lib/npyio.py b/numpy/lib/npyio.py
index 54a37fbad..dc1c951e7 100644
--- a/numpy/lib/npyio.py
+++ b/numpy/lib/npyio.py
@@ -397,7 +397,7 @@ def load(file, mmap_mode=None, allow_pickle=True, fix_imports=True,
 
     try:
         # Code to distinguish from NumPy binary files and pickles.
-        _ZIP_PREFIX = asbytes('PK\x03\x04')
+        _ZIP_PREFIX = b'PK\x03\x04'
         N = len(format.MAGIC_PREFIX)
         magic = fid.read(N)
         # If the file size is less than N, we need to make sure not
@@ -856,7 +856,7 @@ def loadtxt(fname, dtype=float, comments='#', delimiter=None,
 
         # Compile regex for comments beforehand
         comments = (re.escape(comment) for comment in comments)
-        regex_comments = re.compile(asbytes('|').join(comments))
+        regex_comments = re.compile(b'|'.join(comments))
     user_converters = converters
     if delimiter is not None:
         delimiter = asbytes(delimiter)
@@ -958,7 +958,7 @@ def loadtxt(fname, dtype=float, comments='#', delimiter=None,
         line = asbytes(line)
         if comments is not None:
             line = regex_comments.split(asbytes(line), maxsplit=1)[0]
-        line = line.strip(asbytes('\r\n'))
+        line = line.strip(b'\r\n')
         if line:
             return line.split(delimiter)
         else:
@@ -1576,11 +1576,11 @@ def genfromtxt(fname, dtype=float, comments='#', delimiter=None,
             if names is True:
                 if comments in first_line:
                     first_line = (
-                        asbytes('').join(first_line.split(comments)[1:]))
+                        b''.join(first_line.split(comments)[1:]))
             first_values = split_line(first_line)
     except StopIteration:
         # return an empty array if the datafile is empty
-        first_line = asbytes('')
+        first_line = b''
         first_values = []
         warnings.warn('genfromtxt: Empty input file: "%s"' % fname, stacklevel=2)
 
@@ -1605,7 +1605,7 @@ def genfromtxt(fname, dtype=float, comments='#', delimiter=None,
     if names is True:
         names = validate_names([_bytes_to_name(_.strip())
                                 for _ in first_values])
-        first_line = asbytes('')
+        first_line = b''
     elif _is_string_like(names):
         names = validate_names([_.strip() for _ in names.split(',')])
     elif names:
@@ -1644,7 +1644,7 @@ def genfromtxt(fname, dtype=float, comments='#', delimiter=None,
     user_missing_values = missing_values or ()
 
     # Define the list of missing_values (one column: one list)
-    missing_values = [list([asbytes('')]) for _ in range(nbcols)]
+    missing_values = [list([b'']) for _ in range(nbcols)]
 
     # We have a dictionary: process it field by field
     if isinstance(user_missing_values, dict):
@@ -1684,7 +1684,7 @@ def genfromtxt(fname, dtype=float, comments='#', delimiter=None,
                 entry.append(value)
     # We have a string : apply it to all entries
     elif isinstance(user_missing_values, bytes):
-        user_value = user_missing_values.split(asbytes(","))
+        user_value = user_missing_values.split(b",")
         for entry in missing_values:
             entry.extend(user_value)
     # We have something else: apply it to all entries
@@ -1977,7 +1977,7 @@ def genfromtxt(fname, dtype=float, comments='#', delimiter=None,
     if usemask and names:
         for (name, conv) in zip(names or (), converters):
             missing_values = [conv(_) for _ in conv.missing_values
-                              if _ != asbytes('')]
+                              if _ != b'']
             for mval in missing_values:
                 outputmask[name] |= (output[name] == mval)
     # Construct the final array
diff --git a/numpy/lib/tests/test__datasource.py b/numpy/lib/tests/test__datasource.py
index f4bece352..f2ad0344a 100644
--- a/numpy/lib/tests/test__datasource.py
+++ b/numpy/lib/tests/test__datasource.py
@@ -5,7 +5,6 @@ import sys
 from tempfile import mkdtemp, mkstemp, NamedTemporaryFile
 from shutil import rmtree
 
-from numpy.compat import asbytes
 from numpy.testing import (
     run_module_suite, TestCase, assert_, SkipTest
     )
@@ -53,7 +52,7 @@ http_fakefile = 'fake.txt'
 malicious_files = ['/etc/shadow', '../../shadow',
                    '..\\system.dat', 'c:\\windows\\system.dat']
 
-magic_line = asbytes('three is the magic number')
+magic_line = b'three is the magic number'
 
 
 # Utility functions used by many TestCases
diff --git a/numpy/lib/tests/test__iotools.py b/numpy/lib/tests/test__iotools.py
index e0a917a21..db3ee4f90 100644
--- a/numpy/lib/tests/test__iotools.py
+++ b/numpy/lib/tests/test__iotools.py
@@ -5,7 +5,7 @@ import time
 from datetime import date
 
 import numpy as np
-from numpy.compat import asbytes, asbytes_nested
+from numpy.compat import asbytes_nested
 from numpy.testing import (
     run_module_suite, TestCase, assert_, assert_equal, assert_allclose,
     assert_raises
@@ -21,7 +21,7 @@ class TestLineSplitter(TestCase):
 
     def test_no_delimiter(self):
         "Test LineSplitter w/o delimiter"
-        strg = asbytes(" 1 2 3 4  5 # test")
+        strg = b" 1 2 3 4  5 # test"
         test = LineSplitter()(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '5']))
         test = LineSplitter('')(strg)
@@ -29,51 +29,51 @@ class TestLineSplitter(TestCase):
 
     def test_space_delimiter(self):
         "Test space delimiter"
-        strg = asbytes(" 1 2 3 4  5 # test")
-        test = LineSplitter(asbytes(' '))(strg)
+        strg = b" 1 2 3 4  5 # test"
+        test = LineSplitter(b' ')(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '', '5']))
-        test = LineSplitter(asbytes('  '))(strg)
+        test = LineSplitter(b'  ')(strg)
         assert_equal(test, asbytes_nested(['1 2 3 4', '5']))
 
     def test_tab_delimiter(self):
         "Test tab delimiter"
-        strg = asbytes(" 1\t 2\t 3\t 4\t 5  6")
-        test = LineSplitter(asbytes('\t'))(strg)
+        strg = b" 1\t 2\t 3\t 4\t 5  6"
+        test = LineSplitter(b'\t')(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '5  6']))
-        strg = asbytes(" 1  2\t 3  4\t 5  6")
-        test = LineSplitter(asbytes('\t'))(strg)
+        strg = b" 1  2\t 3  4\t 5  6"
+        test = LineSplitter(b'\t')(strg)
         assert_equal(test, asbytes_nested(['1  2', '3  4', '5  6']))
 
     def test_other_delimiter(self):
         "Test LineSplitter on delimiter"
-        strg = asbytes("1,2,3,4,,5")
-        test = LineSplitter(asbytes(','))(strg)
+        strg = b"1,2,3,4,,5"
+        test = LineSplitter(b',')(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '', '5']))
         #
-        strg = asbytes(" 1,2,3,4,,5 # test")
-        test = LineSplitter(asbytes(','))(strg)
+        strg = b" 1,2,3,4,,5 # test"
+        test = LineSplitter(b',')(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '', '5']))
 
     def test_constant_fixed_width(self):
         "Test LineSplitter w/ fixed-width fields"
-        strg = asbytes("  1  2  3  4     5   # test")
+        strg = b"  1  2  3  4     5   # test"
         test = LineSplitter(3)(strg)
         assert_equal(test, asbytes_nested(['1', '2', '3', '4', '', '5', '']))
         #
-        strg = asbytes("  1     3  4  5  6# test")
+        strg = b"  1     3  4  5  6# test"
         test = LineSplitter(20)(strg)
         assert_equal(test, asbytes_nested(['1     3  4  5  6']))
         #
-        strg = asbytes("  1     3  4  5  6# test")
+        strg = b"  1     3  4  5  6# test"
         test = LineSplitter(30)(strg)
         assert_equal(test, asbytes_nested(['1     3  4  5  6']))
 
     def test_variable_fixed_width(self):
-        strg = asbytes("  1     3  4  5  6# test")
+        strg = b"  1     3  4  5  6# test"
         test = LineSplitter((3, 6, 6, 3))(strg)
         assert_equal(test, asbytes_nested(['1', '3', '4  5', '6']))
         #
-        strg = asbytes("  1     3  4  5  6# test")
+        strg = b"  1     3  4  5  6# test"
         test = LineSplitter((6, 6, 9))(strg)
         assert_equal(test, asbytes_nested(['1', '3  4', '5  6']))
 
@@ -157,7 +157,7 @@ class TestStringConverter(TestCase):
         assert_equal(converter._status, 0)
 
         # test int
-        assert_equal(converter.upgrade(asbytes('0')), 0)
+        assert_equal(converter.upgrade(b'0'), 0)
         assert_equal(converter._status, 1)
 
         # On systems where integer defaults to 32-bit, the statuses will be
@@ -166,30 +166,30 @@ class TestStringConverter(TestCase):
         status_offset = int(nx.dtype(nx.integer).itemsize < nx.dtype(nx.int64).itemsize)
 
         # test int > 2**32
-        assert_equal(converter.upgrade(asbytes('17179869184')), 17179869184)
+        assert_equal(converter.upgrade(b'17179869184'), 17179869184)
         assert_equal(converter._status, 1 + status_offset)
 
         # test float
-        assert_allclose(converter.upgrade(asbytes('0.')), 0.0)
+        assert_allclose(converter.upgrade(b'0.'), 0.0)
         assert_equal(converter._status, 2 + status_offset)
 
         # test complex
-        assert_equal(converter.upgrade(asbytes('0j')), complex('0j'))
+        assert_equal(converter.upgrade(b'0j'), complex('0j'))
         assert_equal(converter._status, 3 + status_offset)
 
         # test str
-        assert_equal(converter.upgrade(asbytes('a')), asbytes('a'))
+        assert_equal(converter.upgrade(b'a'), b'a')
         assert_equal(converter._status, len(converter._mapper) - 1)
 
     def test_missing(self):
         "Tests the use of missing values."
-        converter = StringConverter(missing_values=(asbytes('missing'),
-                                                    asbytes('missed')))
-        converter.upgrade(asbytes('0'))
-        assert_equal(converter(asbytes('0')), 0)
-        assert_equal(converter(asbytes('')), converter.default)
-        assert_equal(converter(asbytes('missing')), converter.default)
-        assert_equal(converter(asbytes('missed')), converter.default)
+        converter = StringConverter(missing_values=(b'missing',
+                                                    b'missed'))
+        converter.upgrade(b'0')
+        assert_equal(converter(b'0'), 0)
+        assert_equal(converter(b''), converter.default)
+        assert_equal(converter(b'missing'), converter.default)
+        assert_equal(converter(b'missed'), converter.default)
         try:
             converter('miss')
         except ValueError:
@@ -200,11 +200,11 @@ class TestStringConverter(TestCase):
         dateparser = _bytes_to_date
         StringConverter.upgrade_mapper(dateparser, date(2000, 1, 1))
         convert = StringConverter(dateparser, date(2000, 1, 1))
-        test = convert(asbytes('2001-01-01'))
+        test = convert(b'2001-01-01')
         assert_equal(test, date(2001, 1, 1))
-        test = convert(asbytes('2009-01-01'))
+        test = convert(b'2009-01-01')
         assert_equal(test, date(2009, 1, 1))
-        test = convert(asbytes(''))
+        test = convert(b'')
         assert_equal(test, date(2000, 1, 1))
 
     def test_string_to_object(self):
@@ -215,43 +215,43 @@ class TestStringConverter(TestCase):
 
     def test_keep_default(self):
         "Make sure we don't lose an explicit default"
-        converter = StringConverter(None, missing_values=asbytes(''),
+        converter = StringConverter(None, missing_values=b'',
                                     default=-999)
-        converter.upgrade(asbytes('3.14159265'))
+        converter.upgrade(b'3.14159265')
         assert_equal(converter.default, -999)
         assert_equal(converter.type, np.dtype(float))
         #
         converter = StringConverter(
-            None, missing_values=asbytes(''), default=0)
-        converter.upgrade(asbytes('3.14159265'))
+            None, missing_values=b'', default=0)
+        converter.upgrade(b'3.14159265')
         assert_equal(converter.default, 0)
         assert_equal(converter.type, np.dtype(float))
 
     def test_keep_default_zero(self):
         "Check that we don't lose a default of 0"
         converter = StringConverter(int, default=0,
-                                    missing_values=asbytes("N/A"))
+                                    missing_values=b"N/A")
         assert_equal(converter.default, 0)
 
     def test_keep_missing_values(self):
         "Check that we're not losing missing values"
         converter = StringConverter(int, default=0,
-                                    missing_values=asbytes("N/A"))
+                                    missing_values=b"N/A")
         assert_equal(
             converter.missing_values, set(asbytes_nested(['', 'N/A'])))
 
     def test_int64_dtype(self):
         "Check that int64 integer types can be specified"
         converter = StringConverter(np.int64, default=0)
-        val = asbytes("-9223372036854775807")
+        val = b"-9223372036854775807"
         assert_(converter(val) == -9223372036854775807)
-        val = asbytes("9223372036854775807")
+        val = b"9223372036854775807"
         assert_(converter(val) == 9223372036854775807)
 
     def test_uint64_dtype(self):
         "Check that uint64 integer types can be specified"
         converter = StringConverter(np.uint64, default=0)
-        val = asbytes("9223372043271415339")
+        val = b"9223372043271415339"
         assert_(converter(val) == 9223372043271415339)
 
 
diff --git a/numpy/lib/tests/test_format.py b/numpy/lib/tests/test_format.py
index 7cc72e775..77ac5942a 100644
--- a/numpy/lib/tests/test_format.py
+++ b/numpy/lib/tests/test_format.py
@@ -284,7 +284,7 @@ import warnings
 from io import BytesIO
 
 import numpy as np
-from numpy.compat import asbytes, asbytes_nested, sixu
+from numpy.compat import asbytes_nested, sixu
 from numpy.testing import (
     run_module_suite, assert_, assert_array_equal, assert_raises, raises,
     dec, SkipTest
@@ -546,7 +546,7 @@ def test_pickle_python2_python3():
         xrange = __builtin__.xrange
 
     expected = np.array([None, xrange, sixu('\u512a\u826f'),
-                         asbytes('\xe4\xb8\x8d\xe8\x89\xaf')],
+                         b'\xe4\xb8\x8d\xe8\x89\xaf'],
                         dtype=object)
 
     for fname in ['py2-objarr.npy', 'py2-objarr.npz',
@@ -778,11 +778,11 @@ def test_bad_header():
     # header of length less than 2 should fail
     s = BytesIO()
     assert_raises(ValueError, format.read_array_header_1_0, s)
-    s = BytesIO(asbytes('1'))
+    s = BytesIO(b'1')
     assert_raises(ValueError, format.read_array_header_1_0, s)
 
     # header shorter than indicated size should fail
-    s = BytesIO(asbytes('\x01\x00'))
+    s = BytesIO(b'\x01\x00')
     assert_raises(ValueError, format.read_array_header_1_0, s)
 
     # headers without the exact keys required should fail