finding items that occur more than once in a list

[castironpi at gmail.com]

On Mar 22, 3:31 am, Bryan Olson <fakeaddr... at nowhere.org> wrote:
> castiro... at gmail.com wrote:
> > John Machin wrote:
> >> On Mar 22, 1:11 am, castiro... at gmail.com wrote:
> >>> A collision sequence is not so rare.
> >>>>>> [ hash( 2**i ) for i in range( 0, 256, 32 ) ]
> >>> [1, 1, 1, 1, 1, 1, 1, 1]
> >> Bryan did qualify his remarks: "If we exclude the case where an
> >> adversary is choosing the keys, ..."
>
> > Some adversary.  What, you mean, my boss or my customers?
>
> We mean that the party supplying the keys deliberately chose
> them to make the hash table inefficient. In this thread the goal
> is efficiency; a party working toward an opposing goal is an
> adversary.
>
> If you find real-world data sets that tend to induce bad-case
> behavior in Python's hash, please do tell. It would be reason
> enough to adjust the hash function. The hashes in popular
> software such as Python are already quite well vetted.
>
> Even a hash function that behaves as a random oracle has
> worst-case quadratic-time in the algorithm here, but that's
> an issue in theory and not in serving customers.

Hey Net:

Where -we- left off, all real-world data sets were equally common,
unless you think in peckbird bartenders.  Nuh uh at all, unless you've
got a characterize real-world data project underway.  Did you know
letter frequency distributions vary by domain?  And now for the 2-
squarebar spider.

raise ISay( "Python Science is unusually prone against non-power
multiples of 32 hashing integers", "Unknown value of I" )

parse( 'strangers are perfect' )
parse( 'i think i know someone' )
prevention.value() == 12* cure.value()
   raise SolveFor
   (raise CureValueSterling)
keep: time.value().encode() > money.value()
assert time.value().encode()== time.encode().value()
perch( Out )

compose( Fluctuate )
compose( Punctuate )
compose( Explain )

@partial( partial, prefix ) (ha, h)
raise Distracts( 'Well, would you look at that?' )
   raise LivingConstraint( NoseFalls )
raise Superlative
voice Absolute
raise NonScalar( "Fit: It's apples -over- oranges." )
raise OverPull( "Not on Google." )
raise Drop( "It." )
moment+= instant
raise LeavesImpression
raise GoodMuleTwoHaystacks
raise ScaleDecomposition
raise Bias( 'Discrimination' )
raise BadFor
raise RequestedControlCurrencyExpiration
raise InsufficientTrust
raise Shock
raise EnoughTheory
raise EnoughCustomers
raise EyebrowTwo
raise DataKill
raise Reckless
raise ThenWhat( AfterYou )
raise NotImplemented( 'Offer.refuse' )
raise LaughterUnacceptable
raise Hell
raise DesignUnintelligent
raise HashesPerturbation
raise ProfessionException
yield Tick
yield Tally
yield Ho
yield Gee
yield Whoa
raise ActuallyActuallyActually
raise CurrencyAStream

If you can't fit an analogy...

Bee Dance : Hive Good :: Human This :: Community Good?
What and how is it when to who where?
What does it know?  What does it do but sleep?
Does it specialize, momentarily fair?

Hey, what do you think of the spelling of this?  "The group you are
posting to is a Usenet group. Messages posted to this group will make
your email address visible to anyone on the Internet."  What do you
think of the wording of "spelling"?  Take me to your lexicographer:
wake-up; you're up web, Europe web.  Pass self to a generator.

Dust is sett'ling;
Tables turn:
Water's drying;
Sugars burn.

Phaser fire!
Shoulders square!
join( TenForward )?
Who is where?

Mushroom's growing;
Mighty... falls.
Cauldron's bubbling;
That is all.

>>> def f():
...     n= True
...     while 1:
...             k= yield( n )
...             if k is not None: n= k
...
>>> a= f()
>>> next( a )
True
>>> next( a )
True
>>> next( a )
True
>>> a.send( 2 )
2
>>> next( a )
2
>>> next( a )
2
>>> next( a )
2
>>>