diff options
| -rw-r--r-- | Doc/library/collections.rst | 10 | ||||
| -rw-r--r-- | Lib/collections.py | 14 | ||||
| -rw-r--r-- | Lib/test/test_collections.py | 11 | ||||
| -rw-r--r-- | Misc/NEWS | 4 |
4 files changed, 36 insertions, 3 deletions
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index 6aaeb13..94fd16c 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -617,7 +617,7 @@ Named tuples assign meaning to each position in a tuple and allow for more reada self-documenting code. They can be used wherever regular tuples are used, and they add the ability to access fields by name instead of position index. -.. function:: namedtuple(typename, field_names, [verbose]) +.. function:: namedtuple(typename, field_names, [verbose], [rename]) Returns a new tuple subclass named *typename*. The new subclass is used to create tuple-like objects that have fields accessible by attribute lookup as @@ -635,6 +635,11 @@ they add the ability to access fields by name instead of position index. a :mod:`keyword` such as *class*, *for*, *return*, *global*, *pass*, *print*, or *raise*. + If *rename* is true, invalid fieldnames are automatically replaced + with positional names. For example, ``['abc', 'def', 'ghi', 'abc']`` is + converted to ``['abc', '_2', 'ghi', '_4']``, eliminating the keyword + ``def`` and the duplicate fieldname ``abc``. + If *verbose* is true, the class definition is printed just before being built. Named tuple instances do not have per-instance dictionaries, so they are @@ -642,6 +647,9 @@ they add the ability to access fields by name instead of position index. .. versionadded:: 2.6 + .. versionchanged:: 2.7 + added support for *rename*. + Example: .. doctest:: diff --git a/Lib/collections.py b/Lib/collections.py index 0fddb97..8d49cd5 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -16,7 +16,7 @@ from itertools import repeat as _repeat, chain as _chain, starmap as _starmap, i ### namedtuple ################################################################################ -def namedtuple(typename, field_names, verbose=False): +def namedtuple(typename, field_names, verbose=False, rename=False): """Returns a new subclass of tuple with named fields. >>> Point = namedtuple('Point', 'x y') @@ -45,6 +45,16 @@ def namedtuple(typename, field_names, verbose=False): if isinstance(field_names, basestring): field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas field_names = tuple(map(str, field_names)) + if rename: + names = list(field_names) + seen = set() + for i, name in enumerate(names): + if (not all(c.isalnum() or c=='_' for c in name) or _iskeyword(name) + or not name or name[0].isdigit() or name.startswith('_') + or name in seen): + names[i] = '_%d' % (i+1) + seen.add(name) + field_names = tuple(names) for name in (typename,) + field_names: if not all(c.isalnum() or c=='_' for c in name): raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name) @@ -54,7 +64,7 @@ def namedtuple(typename, field_names, verbose=False): raise ValueError('Type names and field names cannot start with a number: %r' % name) seen_names = set() for name in field_names: - if name.startswith('_'): + if name.startswith('_') and not rename: raise ValueError('Field names cannot start with an underscore: %r' % name) if name in seen_names: raise ValueError('Encountered duplicate field name: %r' % name) diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py index 17ec30c..4901eae 100644 --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -44,6 +44,17 @@ class TestNamedTuple(unittest.TestCase): self.assertRaises(TypeError, Point._make, [11]) # catch too few args self.assertRaises(TypeError, Point._make, [11, 22, 33]) # catch too many args + def test_name_fixer(self): + for spec, renamed in [ + [('efg', 'g%hi'), ('efg', '_2')], # field with non-alpha char + [('abc', 'class'), ('abc', '_2')], # field has keyword + [('8efg', '9ghi'), ('_1', '_2')], # field starts with digit + [('abc', '_efg'), ('abc', '_2')], # field with leading underscore + [('abc', 'efg', 'efg', 'ghi'), ('abc', 'efg', '_3', 'ghi')], # duplicate field + [('abc', '', 'x'), ('abc', '_2', 'x')], # fieldname is a space + ]: + self.assertEqual(namedtuple('NT', spec, rename=True)._fields, renamed) + def test_instance(self): Point = namedtuple('Point', 'x y') p = Point(11, 22) @@ -155,6 +155,10 @@ Library - Issue #5122: Synchronize tk load failure check to prevent a potential deadlock. +- Issue #1818: collections.namedtuple() now supports a keyword argument + 'rename' which lets invalid fieldnames be automatically converted to + positional names in the form, _1, _2, ... + - Issue #4890: Handle empty text search pattern in Tkinter.Text.search. - Issue #5170: Fixed Unicode output bug in logging and added test case. |