# [plt-scheme] eqv? equal?

 From: Jens Axel Soegaard (jensaxel at soegaard.net) Date: Sun Mar 1 15:01:11 EST 2009 Previous message: [plt-scheme] eqv? equal? Next message: [plt-scheme] eqv? equal? Messages sorted by: [date] [thread] [subject] [author]

``` >     emre berat nebiog(lu skrev:
>
>         Sorry for this newbie question.But i wonder so much about eqv?
>         and equal?.In the some discussin that passes on ffreenode
>         #scheme.I see some sentence which is "eqv? is faster than equal?
>         in comparison.So i thought eqv? and equal? returns boolean thing
>         #t or #f right ? So why?
>
>         In that point,i have three question about that.
>
>         what is the thing that makes eqv? faster than equal?.
>
>         which one is more powerful on programming  ?
>
>         What is the reason that equal? still be used ? If eqv? is faster
>         than equal?.
>
>
>
>
http://www.schemers.org/Documents/Standards/R5RS/HTML/r5rs-Z-H-9.html#%_sec_6.1
>
>     Try to predict the result of:
>
>      (eqv? (list 1 2) (list 1 2))
>
>     and
>
>      (equal? (list 1 2) (list 1 2))
>
>
>     What happens and why?

emre berat nebiog(lu skrev:
> eqv returns false.
>
> equal returns true.
>
> i learn new things so eqv? and equal? is not the same thing.But i cannot

(eqv? p1 p2) checks whether p1 and p2 is the same pair
(i.e. located the same place in memory - and thus is a simple
pointer comparision)

(equal? p1 p2) checks recursively whether the contents of the
the car and cdr of the pairs are the same.

--
Jens Axel Søgaard

```

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