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.

--
Norvell Spearman

[Raymond Hettinger]

> [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.
Raymond Hettinger

[Jeffrey Schwab]

Raymond Hettinger wrote:

[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]

Raymond Hettinger wrote:

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

[Norvell Spearman]

Jeffrey Schwab wrote:

TMTOWTDI, after all. :)

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

--
Norvell Spearman

[Bernhard Herzog]

Norvell Spearman <no*****@stenocall.com> writes:

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

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