list assignment

[Norvell Spearman]

In "Learning Python," by Lutz and Ascher, there's a table showing different
assignment statement forms. One form shown is list assignment. The authors
give this as an example:

[spam, ham] = ['yum', 'YUM']

I don't see how this is any different than a tuple unpacking assignment:

>>> a, b = 1, 2
>>> a, b (1, 2)
>>> [a, b] = [1, 2]
>>> a, b

(1, 2)

In both instances the names a and b are both mapped to 1 and 2 so why are there
two different forms?

Thanks for any answers.

 

[Raymond Hettinger]

[spam, ham] = ['yum', 'YUM']

I don't see how this is any different than a tuple unpacking assignment:

It's not different. They are ways of writing the same thing.


Raymond Hettinger

 

[Jeffrey Schwab]

[spam, ham] = ['yum', 'YUM']

I don't see how this is any different than a tuple unpacking assignment:

a, b = 1, 2

It's not different. They are ways of writing the same thing.

TMTOWTDI, after all.

 

[Norvell Spearman]

It's not different. They are ways of writing the same thing.

Lutz and Ascher have tuple and list assignment as separate entries in their
assignment statement forms table so I was expecting there to be some
difference; thanks for setting me straight.

 

[Norvell Spearman]

TMTOWTDI, after all.

A bit ironic that that's the official motto of Perl, don't you think?

 

[Bernhard Herzog]

Lutz and Ascher have tuple and list assignment as separate entries in
their assignment statement forms table so I was expecting there to be
some difference; thanks for setting me straight.

In older Python versions there was a difference between list unpacking
and tuple unpacking. The former would only work with lists and the
latter with tuples. With Python 1.5, both were unified into a more
general sequence unpacking, but for backwards compatibility both
syntaxes were kept.

Bernhard