[Python-Dev] Retrieve an arbitrary element from a set withoutremoving it (original) (raw)

Georg Brandl g.brandl at gmx.net
Fri Oct 30 21:37:36 CET 2009

Steven D'Aprano schrieb:

On Wed, 28 Oct 2009 04:47:59 am Raymond Hettinger wrote:

A dict.get() can be meaningfully used in a loop (because the key can vary). A set.get() returns the same value over and over again (because there is no key). I don't believe anyone has requested those semantics. The suggested semantics for set.get() with no arguments, as I understand them, are: (1) it will only fail if the set is empty; (2) it should be efficient; (3) if you call it repeatedly on a set without modifying the set, you will cycle through each element in turn in some unspecified arbitrary order.

I don't like this. It gives a set object a hidden state, something that AFAICS no other builtin has. Iterating over an iterable is what iterators are for.

Georg

-- Thus spake the Lord: Thou shalt indent with four spaces. No more, no less. Four shall be the number of spaces thou shalt indent, and the number of thy indenting shall be four. Eight shalt thou not indent, nor either indent thou two, excepting that thou then proceed to four. Tabs are right out.

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