Merged revisions 69466,69480 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r69466 | raymond.hettinger | 2009-02-09 12:39:41 -0600 (Mon, 09 Feb 2009) | 3 lines
Issue 5171: itertools.product docstring missing 'repeat' argument
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r69480 | raymond.hettinger | 2009-02-09 19:24:05 -0600 (Mon, 09 Feb 2009) | 1 line
Issue 1818: collections.namedtuple() to support automatic renaming of invalid fieldnames.
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diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 32cc639..9ff8a27 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -597,7 +597,7 @@
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
@@ -615,11 +615,19 @@
a :mod:`keyword` such as *class*, *for*, *return*, *global*, *pass*,
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
lightweight and require no more memory than regular tuples.
+ .. versionchanged:: 2.7
+ added support for *rename*.
+
Example:
.. doctest::
diff --git a/Lib/collections.py b/Lib/collections.py
index 512cf28..f8392b6 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -18,7 +18,7 @@
### 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')
@@ -47,6 +47,16 @@
if isinstance(field_names, str):
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)
@@ -56,7 +66,7 @@
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 c0cc016..1127910 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -47,6 +47,17 @@
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)
diff --git a/Misc/NEWS b/Misc/NEWS
index aebbcde..7a4fb9e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -170,6 +170,10 @@
- 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 #4512 (part 2): Promote ``ZipImporter._get_filename()`` to be a
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 58c30f9..9245b1f 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -1791,6 +1791,9 @@
The leftmost iterators are in the outermost for-loop, so the output tuples\n\
cycle in a manner similar to an odometer (with the rightmost element changing\n\
on every iteration).\n\n\
+To compute the product of an iterable with itself, specify the number\n\
+of repetitions with the optional repeat keyword argument. For example,\n\
+product(A, repeat=4) means the same as product(A, A, A, A).\n\n\
product('ab', range(3)) --> ('a',0) ('a',1) ('a',2) ('b',0) ('b',1) ('b',2)\n\
product((0,1), (0,1), (0,1)) --> (0,0,0) (0,0,1) (0,1,0) (0,1,1) (1,0,0) ...");