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Re: What meaning of this ""hello %s you are %s years old" % x"

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Date Sun, 27 Jul 2014 14:37:19 -0700
Subject Re: What meaning of this ""hello %s you are %s years old" % x"
From Dan Stromberg <drsalists@gmail.com>
To fl <rxjwg98@gmail.com>
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On Sun, Jul 27, 2014 at 11:49 AM, fl <rxjwg98@gmail.com> wrote:
> In Python, when should you use lists and when tuples?
>
> Sometimes you don't have a choice, for example if you have
>
> "hello %s you are %s years old" % x
> then x must be a tuple.
>
> But if I am the one who designs the API and gets to choose the data types, then
> what are the guidelines?

You should use a tuple when you need something immutable (readonly),
like a dictionary key.  Immutable objects are good for hashing.

You should use a list when you need something mutable (read/write),
like appending over and over.  Mutable objects are not good for
hashing, because their hash value could change.

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Thread

What meaning of this ""hello %s you are %s years old" % x" fl <rxjwg98@gmail.com> - 2014-07-27 11:49 -0700
  Re: What meaning of this ""hello %s you are %s years old" % x" Gary Herron <gary.herron@islandtraining.com> - 2014-07-27 13:02 -0700
  Re: What meaning of this ""hello %s you are %s years old" % x" Dan Stromberg <drsalists@gmail.com> - 2014-07-27 14:37 -0700
  Re: What meaning of this ""hello %s you are %s years old" % x" Albert-Jan Roskam <fomcl@yahoo.com> - 2014-07-28 00:41 -0700
  Re: What meaning of this ""hello %s you are %s years old" % x" Chris Angelico <rosuav@gmail.com> - 2014-07-28 17:58 +1000

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