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Re: Can tuples be replaced with lists all the time?

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Sam <lightaiyee@gmail.com> writes:

> My understanding of Python tuples is that they are like immutable
> lists.

That's a common expression, but I think it's not a helpful way to think
of them.

Rather, the different sequence types have different semantic purposes:

* For representing a sequence where each item means exactly the same no
  matter which position it's in (a “homogeneous sequence”), use a list.

* For representing a sequence where the meaning of each item is strongly
  dependent on its position in the sequence (a “heterogeneous
  sequence”), use a tuple.

See <URL:http://docs.python.org/3/library/stdtypes.html> for the
official Python description of the type differences.

> If this is the cause, why can't we replace tuples with lists all the
> time (just don't reassign the lists)? Correct me if I am wrong.

Because we need to represent different semantic concepts in our code,
and have each type support the semantics with different operations.

-- 
 \     “I went camping and borrowed a circus tent by mistake. I didn't |
  `\      notice until I got it set up. People complained because they |
_o__)                           couldn't see the lake.” —Steven Wright |
Ben Finney

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Thread

Can tuples be replaced with lists all the time? Sam <lightaiyee@gmail.com> - 2014-02-22 20:06 -0800
  Re: Can tuples be replaced with lists all the time? Paul Rubin <no.email@nospam.invalid> - 2014-02-22 20:28 -0800
  Re: Can tuples be replaced with lists all the time? Chris Angelico <rosuav@gmail.com> - 2014-02-23 15:18 +1100
  Re: Can tuples be replaced with lists all the time? Ben Finney <ben+python@benfinney.id.au> - 2014-02-23 15:49 +1100
  Re: Can tuples be replaced with lists all the time? 88888 Dihedral <dihedral88888@gmail.com> - 2014-02-23 11:45 -0800
  Re: Can tuples be replaced with lists all the time? Roy Smith <roy@panix.com> - 2014-02-22 23:19 -0500
    Re: Can tuples be replaced with lists all the time? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-03-02 17:21 -0500
  Re: Can tuples be replaced with lists all the time? Grant Edwards <invalid@invalid.invalid> - 2014-02-23 17:07 +0000
    Re: Can tuples be replaced with lists all the time? Roy Smith <roy@panix.com> - 2014-02-23 12:48 -0500
      Re: Can tuples be replaced with lists all the time? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-01 21:20 +0000
      Re: Can tuples be replaced with lists all the time? Terry Reedy <tjreedy@udel.edu> - 2014-03-01 18:15 -0500

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