Bugs item #1119418, was opened at 2005-02-09 11:57
Message generated for change (Comment added) made by tjreedy
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Category: Python Library
Group: None
Status: Open
Resolution: None
Priority: 6
Submitted By: Martin Blais (blais)
Assigned to: Nobody/Anonymous (nobody)
Summary: xrange() builtin accepts keyword arg silently
Initial Comment:
Calling ``xrange(10, 100, step=10)`` results in a
xrange(10, 100) iterator silently. In contrast,
``range(10, 100, step=10)`` raises an exception. See
test program below.
Two possible fixes:
1. fix xrange() so that it returns a xrange(10, 100,
10) iterator
2. make sure that xrange() raises an exception too.
#!/usr/bin/env python
def foo( min_, max_, step=1 ):
print min_, max_, step
print '===================='
foo(10, 100, 10)
foo(10, 100, step=10)
print '===================='
print xrange(10, 100, 10)
print xrange(10, 100, step=10)
print '===================='
print range(10, 100, 10)
print range(10, 100, step=10)
elbow:/usr/.../lib/python2.4$ /tmp/a.py
====================
10 100 10
10 100 10
====================
xrange(10, 100, 10)
xrange(10, 100)
====================
[10, 20, 30, 40, 50, 60, 70, 80, 90]
Traceback (most recent call last):
File "/tmp/a.py", line 16, in ?
print range(10, 100, step=10)
TypeError: range() takes no keyword arguments
> /tmp/a.py(16)?()
-> print range(10, 100, step=10)
(Pdb)
elbow:/usr/.../lib/python2.4$
----------------------------------------------------------------------
Comment By: Terry J. Reedy (tjreedy)
Date: 2005-02-16 17:21
Message:
Logged In: YES
user_id=593130
Functions coded in C generally do not take keyword
arguments. (Special coding is required to achieve
otherwise.) In 2.2, range and xrange both followed this rule:
>>> xrange(1,20,step=2)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: xrange() takes no keyword arguments
>>> range(1,20,step=2)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: range() takes no keyword arguments
So, removal of the error message by 2.4 seem to be a bug.
Surprise:
>>> str(object=1)
'1'
>>> str(i=2)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: 'i' is an invalid keyword argument for this function
There is nothing in the doc(Lib Ref) or doc string of str vs.
range and xrange that would lead me to expect this.
I looked around CVS a bit to see if the past or possible future
change was something simple, but I could not find source of
error message in bltinmodule.c, ceval.c, getargs.c,
rangeobject.c, or typeobject.c, so I will leave this to
someone else.
----------------------------------------------------------------------
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