maybe a bug in python

[flyaflya]

>>> a = {1: ("a")}
>>> a[1]

'a'
why not ('a')? when

>>> a = {1: ((("a")))}
>>> a[1]

'a'
the result is 'a' too,not ((("a"))).but when use["a"] or ("a","b"),the
tuple is longer than 1, it's no problem.

 

[Will McGugan]

a = {1: ("a")}
a[1]

'a'
why not ('a')? when

a = {1: ((("a")))}
a[1]

'a'
the result is 'a' too,not ((("a"))).but when use["a"] or ("a","b"),the
tuple is longer than 1, it's no problem.

("a") is just a simple expression. You need to add a comma so that
Python knows you want a tuple. Thusly... ("a",)


Will McGugan

 

[Torsten Bronger]

Hallöchen!

a = {1: ("a")}
a[1]

'a'
why not ('a')?

("a") is not a tuple, but ("a",) is.

Tschö,
Torsten.

 

[Steve Horsley]

a = {1: ("a")}
a[1]

'a'
why not ('a')? when

a = {1: ((("a")))}
a[1]

'a'
the result is 'a' too,not ((("a"))).but when use["a"] or ("a","b"),the
tuple is longer than 1, it's no problem.

To define a tuple literal with one member, you must place a comma
after the first element like this:

a = {1: ("a",)}

I read this somewhere in the python docs, so I know its there
somewhere.

The comma eliminates ambiguity as to the meaning of the brackets,
which without the comma are simply enclosing and precedence
controlling brackets.

Steve

 

[Ivan Van Laningham]

Hi All--
This little gotcha ought to be number one on "The Official List of
Pythonic Gotchas," which should be required reading for everyone.

What? There isn't one? Why not?

Send me your tired, your poor, your huddled gotchas yearning to breathe
free. I'll whup 'em into shape and make a doc page. The gods of
documentation (as opposed to the gods _in_ documentation) can transfer
it to the Official Documentation Homeland, or not, as they see fit.

Metta,
Ivan

Just as everyone said, use ('a',) instead of ('a'). As Steve said
there are lots of documentation about it. Check the Library Reference
at http://www.python.org/doc/current/lib/typesseq.html#l2h-155 or to
make things more clear you could read the tuples section in the
tutorial at
http://docs.python.org/tut/node7.html#SECTION007300000000000000000

my 2 cents

Regards,
Tiago S Daitx

a = {1: ("a")}
a[1]

'a'
why not ('a')? when

a = {1: ((("a")))}
a[1]

'a'
the result is 'a' too,not ((("a"))).but when use["a"] or
("a","b"),the
tuple is longer than 1, it's no problem.

--
----------------------------------------------
Ivan Van Laningham
God N Locomotive Works
http://www.pauahtun.org/
http://www.foretec.com/python/workshops/1998-11/proceedings.html
Army Signal Corps: Cu Chi, Class of '70
Author: Teach Yourself Python in 24 Hours

 

[alex23]

This little gotcha ought to be number one on "The Official List of
Pythonic Gotchas," which should be required reading for everyone.

What? There isn't one? Why not?

There's at least one active "Python Gotchas" page out there:
http://www.ferg.org/projects/python_gotchas.html

The last update was in April.

-alex23

 

[gene tani]

or Norvig's IAQ:

http://www.norvig.com/python-iaq.html