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length of a tuple or a list containing only one element

TP
Hi everybody,

I have a question about the difference of behavior of "len" when applied on
tuples or on lists. I mean:

$ len( ( 'foo', 'bar' ) )
2
$ len( ( 'foo' ) )
3
$ len( [ 'foo', 'bar' ] )
2
$ len( [ 'foo' ] )
1

Why this behavior for the length computation of a tuple?
For my application, I prefer the behavior of length for a list. If I want to
store some values in a tuple because they should not be modified, the case
where the tuple contains only one element bothers me.

Thanks

Julien
--
python -c "print ''.join([chr(154 - ord(c)) for c in '*9(9&(18%.9&1+ ,\'Z
(55l4('])"

"When a distinguished but elderly scientist states that something is
possible, he is almost certainly right. When he states that something is
impossible, he is very probably wrong." (first law of AC Clarke)
Nov 3 '08
10 1511
>>For making a literal tuple, parentheses are irrelevant; only the
>>commas matter:
I don't think I'd go so far as to say that the parentheses around tuples
are *irrelevant*... maybe just relevant in select contexts
> >>def foo(*args):
... for i, arg in enumerate(args) :
... print i, arg
...
> >>foo(1,2)
0 1
1 2
> >>foo((1,2)) # these parens are pretty important :)
0 (1, 2)

pedantically-grinning-ducktyping-and-running-ly yers,

I'll see your pedantry and raise you one:
>>foo()
>>foo(())
0 ()
And just because another "tuples without parens" case exists:
>>foo(,)
File "<stdin>", line 1
foo(,)
^
SyntaxError: invalid syntax

To maintain the poker theme, I'd say "You raised, and I call" but
my call fails :-P

-tkc

Nov 3 '08 #11

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