Re: contains? for vectors
and obviously I would like it to throw here instead :) but hey, that's just
me - overly obsessed with fail-fast rather that performance first or
tolerance
On Fri, Mar 1, 2013 at 9:12 PM, AtKaaZ wrote:
> user=> (contains? "abc" 1.5)
> true
>
> looks like for that, it's coerced to int
>
> else if(key instanceof Number && (coll instanceof String ||
> coll.getClass().isArray())) {
> int n = ((Number) key).intValue();
> return n >= 0 && n < count(coll);
> }
> => (int 1.4)
> 1
> => (int 1.6)
> 1
> => (.intValue 1.4)
> 1
> => (.intValue 1.6)
> 1
>
>
>
> On Fri, Mar 1, 2013 at 9:05 PM, Michael Gardner wrote:
>
>> On Mar 1, 2013, at 13:36 , AtKaaZ wrote:
>>
>> > I don't think I understand what you mean (could you rephrase/example?),
>> I cannot think of a case when I wouldn't want it to throw when I'm passing
>> a non-number (contains? [:a :b :c] :a), I mean, rather than just silently
>> ignoring.
>>
>> I'm talking about a case where you have one or more associative
>> containers of unknown types, and you want to be able to generically ask
>> them whether they contain a particular key. E.g.:
>>
>> (defn has-foo? [c] ;; c is only known to be Associative
>> (contains? c :foo))
>>
>> Insofar as a vector can be viewed as a kind of associative container, one
>> might expect/desire this code to just return false if c happens to be a
>> vector. One could see this as a question about the contract promised by the
>> Associative interface: is is always OK to ask an Associative container
>> whether it contains a given key, or are implementations free to accept only
>> certain kinds of keys? I could go either way on that personally, but I
>> can't find any docs that support one interpretation or the other.
>>
>> > It;s not unlike this:
>> > => (contains? '(:a :b :c) :a)
>> > IllegalArgumentException contains? not supported on type:
>> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>> >
>> > it throws because, it's similarly better than just ignoring it and
>> propagating the bug somewhere else.
>>
>> Different case, because lists aren't Associative.
>>
>> > In a way, it's already so for String:
>> > => (contains? "aaa" 1)
>> > true
>> > => (contains? "aaa" 3)
>> > false
>> > => (contains? "aaa" "a")
>> > IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>> > => (contains? "aaa" 'a)
>> > IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>>
>> This one's actually quite surprising to me. I don't know why 'contains?
>> throws when given a String and a non-numeric argument, since that's
>> inconsistent with its behavior on vectors (and the exception's description
>> seems inaccurate, since 'contains? *is* supported on Strings). Even more
>> strangely:
>>
>> user=> (contains? "abc" 1.5)
>> true
>>
>> I have no explanation for this.
>>
>> --
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
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>>
>>
>
>
> --
> Please correct me if I'm wrong or incomplete,
> even if you think I'll subconsciously hate it.
>
>
--
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Re: contains? for vectors
user=> (contains? "abc" 1.5)
true
looks like for that, it's coerced to int
else if(key instanceof Number && (coll instanceof String ||
coll.getClass().isArray())) {
int n = ((Number) key).intValue();
return n >= 0 && n < count(coll);
}
=> (int 1.4)
1
=> (int 1.6)
1
=> (.intValue 1.4)
1
=> (.intValue 1.6)
1
On Fri, Mar 1, 2013 at 9:05 PM, Michael Gardner wrote:
> On Mar 1, 2013, at 13:36 , AtKaaZ wrote:
>
> > I don't think I understand what you mean (could you rephrase/example?),
> I cannot think of a case when I wouldn't want it to throw when I'm passing
> a non-number (contains? [:a :b :c] :a), I mean, rather than just silently
> ignoring.
>
> I'm talking about a case where you have one or more associative containers
> of unknown types, and you want to be able to generically ask them whether
> they contain a particular key. E.g.:
>
> (defn has-foo? [c] ;; c is only known to be Associative
> (contains? c :foo))
>
> Insofar as a vector can be viewed as a kind of associative container, one
> might expect/desire this code to just return false if c happens to be a
> vector. One could see this as a question about the contract promised by the
> Associative interface: is is always OK to ask an Associative container
> whether it contains a given key, or are implementations free to accept only
> certain kinds of keys? I could go either way on that personally, but I
> can't find any docs that support one interpretation or the other.
>
> > It;s not unlike this:
> > => (contains? '(:a :b :c) :a)
> > IllegalArgumentException contains? not supported on type:
> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
> >
> > it throws because, it's similarly better than just ignoring it and
> propagating the bug somewhere else.
>
> Different case, because lists aren't Associative.
>
> > In a way, it's already so for String:
> > => (contains? "aaa" 1)
> > true
> > => (contains? "aaa" 3)
> > false
> > => (contains? "aaa" "a")
> > IllegalArgumentException contains? not supported on type:
> java.lang.String clojure.lang.RT.contains (RT.java:724)
> > => (contains? "aaa" 'a)
> > IllegalArgumentException contains? not supported on type:
> java.lang.String clojure.lang.RT.contains (RT.java:724)
>
> This one's actually quite surprising to me. I don't know why 'contains?
> throws when given a String and a non-numeric argument, since that's
> inconsistent with its behavior on vectors (and the exception's description
> seems inaccurate, since 'contains? *is* supported on Strings). Even more
> strangely:
>
> user=> (contains? "abc" 1.5)
> true
>
> I have no explanation for this.
>
> --
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
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--
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even if you think I'll subconsciously hate it.
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Re: contains? for vectors
Right, but I'm only after the when-invalid-key is passed:
valid:
=> (contains? "abc" 1)
true
=> (contains? ["a" "b" "c"] 1)
true
invalid:
=> (contains? "abc" "a")
IllegalArgumentException contains? not supported on type: java.lang.String
clojure.lang.RT.contains (RT.java:724)
=> (contains? ["a" "b" "c"] "a")
false
On Fri, Mar 1, 2013 at 9:02 PM, Maik Schünemann
wrote:
> the old contails? debate :)
> contains? is only intented for associative collections. This explains
> (somewhat) the behavior on vectors.
> They are seen as assocuative collections from indexes to values.
> I'm not exactly sure about this, but I expect
> (contains? c x) to be true if you can call (get c x). (and get a truthy
> result except if the value is defined but nil)
> To test if a sequential collection contains the value just call .contains
> or use the (some #{x} c) idiom.
>
> The name IS misleading but after you read the docs it should be clear so i
> don't think the behaviour of contains? has to be changed.
> Greetings
>
>
> On Fri, Mar 1, 2013 at 8:36 PM, AtKaaZ wrote:
>
>> I don't think I understand what you mean (could you rephrase/example?), I
>> cannot think of a case when I wouldn't want it to throw when I'm passing a
>> non-number (contains? [:a :b :c] :a), I mean, rather than just silently
>> ignoring.
>> It;s not unlike this:
>> => (contains? '(:a :b :c) :a)
>>
>> IllegalArgumentException contains? not supported on type:
>> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>>
>> it throws because, it's similarly better than just ignoring it and
>> propagating the bug somewhere else.
>>
>> I don't know about others but, I would prefer if the constraints of a
>> function's definition are violated by ie. devs calling it wrongly (maybe
>> not even anticipating that it could be called wrongly due to it being like
>> generic - perhaps in a manner that you've explained and I didn't quite
>> understand) are enforced and exceptions thrown rather than silently
>> ignoring therefore allowing subtle bugs.
>>
>> In a way, it's already so for String:
>> => (contains? "aaa" 1)
>> true
>> => (contains? "aaa" 3)
>> false
>> => (contains? "aaa" "a")
>>
>> IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>> => (contains? "aaa" 'a)
>>
>> IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>>
>> Where it's almost as what I'd want for vector to be, namely: the valid
>> keys numbers, are allowed, but when invalid keys are used ie. symbol or
>> other strings, then exception is thrown; but not so for vectors; Granted
>> that the exception thrown seems to be saying something other than: bad key
>> type for passed collection (or so) but still...
>>
>> => (contains? [1 3 4] 2)
>> true
>> => (contains? [1 3 4] '2)
>> true
>> => (contains? [1 3 4] "2")
>> false
>>
>> So if you were to use this generically on any collection, you'd maybe
>> expect it to throw for vector as it does for string collection.
>>
>> Thanks for replying, Michael.
>>
>>
>> On Fri, Mar 1, 2013 at 6:03 PM, Michael Gardner wrote:
>>
>>> On Feb 28, 2013, at 17:17 , AtKaaZ wrote:
>>>
>>> > According to this, can a vector have keys that are not numbers? like
>>> :a , if not, then wouldn't it make more sense that
>>> > (contains? [:a :b :c] :a) would throw ? It's probably just me.
>>>
>>> This is a reasonable point, and one I haven't seen made before. The only
>>> problem I can see with throwing an exception is that one might sometimes
>>> wish to deal with associative containers in a generic fashion, and thus end
>>> up asking a vector if it contains a keyword or a string without doing so
>>> explicitly. In that case you'd not want it to throw an exception any more
>>> than the other associative collection types would.
>>>
>>> --
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "Clojure" group.
>>> To post to this group, send email to clojure@googlegroups.com
>>> Note that posts from new members are moderated - please be patient with
>>> your first post.
>>> To unsubscribe from this group, send email to
>>> clojure+unsubscr...@googlegroups.com
>>> For more options, visit this group at
>>> http://groups.google.com/group/clojure?hl=en
>>> ---
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>>> Groups "Clojure" group.
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>>> an email to clojure+unsubscr...@googlegroups.com.
>>> For more options, visit https://groups.google.com/groups/opt_out.
>>>
>>>
>>>
>>
>>
>> --
>> Please correct me if I'm wrong or incomplete,
>> even if you think I'll subconsciously hate it.
>>
>> --
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
>> To post to this group, send email to clojure@googlegroups.com
>> Note that posts from new members are moderated - please b
Re: contains? for vectors
On Mar 1, 2013, at 13:36 , AtKaaZ wrote: > I don't think I understand what you mean (could you rephrase/example?), I > cannot think of a case when I wouldn't want it to throw when I'm passing a > non-number (contains? [:a :b :c] :a), I mean, rather than just silently > ignoring. I'm talking about a case where you have one or more associative containers of unknown types, and you want to be able to generically ask them whether they contain a particular key. E.g.: (defn has-foo? [c] ;; c is only known to be Associative (contains? c :foo)) Insofar as a vector can be viewed as a kind of associative container, one might expect/desire this code to just return false if c happens to be a vector. One could see this as a question about the contract promised by the Associative interface: is is always OK to ask an Associative container whether it contains a given key, or are implementations free to accept only certain kinds of keys? I could go either way on that personally, but I can't find any docs that support one interpretation or the other. > It;s not unlike this: > => (contains? '(:a :b :c) :a) > IllegalArgumentException contains? not supported on type: > clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724) > > it throws because, it's similarly better than just ignoring it and > propagating the bug somewhere else. Different case, because lists aren't Associative. > In a way, it's already so for String: > => (contains? "aaa" 1) > true > => (contains? "aaa" 3) > false > => (contains? "aaa" "a") > IllegalArgumentException contains? not supported on type: java.lang.String > clojure.lang.RT.contains (RT.java:724) > => (contains? "aaa" 'a) > IllegalArgumentException contains? not supported on type: java.lang.String > clojure.lang.RT.contains (RT.java:724) This one's actually quite surprising to me. I don't know why 'contains? throws when given a String and a non-numeric argument, since that's inconsistent with its behavior on vectors (and the exception's description seems inaccurate, since 'contains? *is* supported on Strings). Even more strangely: user=> (contains? "abc" 1.5) true I have no explanation for this. -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
the old contails? debate :)
contains? is only intented for associative collections. This explains
(somewhat) the behavior on vectors.
They are seen as assocuative collections from indexes to values.
I'm not exactly sure about this, but I expect
(contains? c x) to be true if you can call (get c x). (and get a truthy
result except if the value is defined but nil)
To test if a sequential collection contains the value just call .contains
or use the (some #{x} c) idiom.
The name IS misleading but after you read the docs it should be clear so i
don't think the behaviour of contains? has to be changed.
Greetings
On Fri, Mar 1, 2013 at 8:36 PM, AtKaaZ wrote:
> I don't think I understand what you mean (could you rephrase/example?), I
> cannot think of a case when I wouldn't want it to throw when I'm passing a
> non-number (contains? [:a :b :c] :a), I mean, rather than just silently
> ignoring.
> It;s not unlike this:
> => (contains? '(:a :b :c) :a)
>
> IllegalArgumentException contains? not supported on type:
> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>
> it throws because, it's similarly better than just ignoring it and
> propagating the bug somewhere else.
>
> I don't know about others but, I would prefer if the constraints of a
> function's definition are violated by ie. devs calling it wrongly (maybe
> not even anticipating that it could be called wrongly due to it being like
> generic - perhaps in a manner that you've explained and I didn't quite
> understand) are enforced and exceptions thrown rather than silently
> ignoring therefore allowing subtle bugs.
>
> In a way, it's already so for String:
> => (contains? "aaa" 1)
> true
> => (contains? "aaa" 3)
> false
> => (contains? "aaa" "a")
>
> IllegalArgumentException contains? not supported on type:
> java.lang.String clojure.lang.RT.contains (RT.java:724)
> => (contains? "aaa" 'a)
>
> IllegalArgumentException contains? not supported on type:
> java.lang.String clojure.lang.RT.contains (RT.java:724)
>
> Where it's almost as what I'd want for vector to be, namely: the valid
> keys numbers, are allowed, but when invalid keys are used ie. symbol or
> other strings, then exception is thrown; but not so for vectors; Granted
> that the exception thrown seems to be saying something other than: bad key
> type for passed collection (or so) but still...
>
> => (contains? [1 3 4] 2)
> true
> => (contains? [1 3 4] '2)
> true
> => (contains? [1 3 4] "2")
> false
>
> So if you were to use this generically on any collection, you'd maybe
> expect it to throw for vector as it does for string collection.
>
> Thanks for replying, Michael.
>
>
> On Fri, Mar 1, 2013 at 6:03 PM, Michael Gardner wrote:
>
>> On Feb 28, 2013, at 17:17 , AtKaaZ wrote:
>>
>> > According to this, can a vector have keys that are not numbers? like :a
>> , if not, then wouldn't it make more sense that
>> > (contains? [:a :b :c] :a) would throw ? It's probably just me.
>>
>> This is a reasonable point, and one I haven't seen made before. The only
>> problem I can see with throwing an exception is that one might sometimes
>> wish to deal with associative containers in a generic fashion, and thus end
>> up asking a vector if it contains a keyword or a string without doing so
>> explicitly. In that case you'd not want it to throw an exception any more
>> than the other associative collection types would.
>>
>> --
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
>> To post to this group, send email to clojure@googlegroups.com
>> Note that posts from new members are moderated - please be patient with
>> your first post.
>> To unsubscribe from this group, send email to
>> clojure+unsubscr...@googlegroups.com
>> For more options, visit this group at
>> http://groups.google.com/group/clojure?hl=en
>> ---
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>> "Clojure" group.
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>> email to clojure+unsubscr...@googlegroups.com.
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>>
>>
>>
>
>
> --
> Please correct me if I'm wrong or incomplete,
> even if you think I'll subconsciously hate it.
>
> --
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to clojure@googlegroups.com
> Note that posts from new members are moderated - please be patient with
> your first post.
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> clojure+unsubscr...@googlegroups.com
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Re: contains? for vectors
I don't think I understand what you mean (could you rephrase/example?), I cannot think of a case when I wouldn't want it to throw when I'm passing a non-number (contains? [:a :b :c] :a), I mean, rather than just silently ignoring. It;s not unlike this: => (contains? '(:a :b :c) :a) IllegalArgumentException contains? not supported on type: clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724) it throws because, it's similarly better than just ignoring it and propagating the bug somewhere else. I don't know about others but, I would prefer if the constraints of a function's definition are violated by ie. devs calling it wrongly (maybe not even anticipating that it could be called wrongly due to it being like generic - perhaps in a manner that you've explained and I didn't quite understand) are enforced and exceptions thrown rather than silently ignoring therefore allowing subtle bugs. In a way, it's already so for String: => (contains? "aaa" 1) true => (contains? "aaa" 3) false => (contains? "aaa" "a") IllegalArgumentException contains? not supported on type: java.lang.String clojure.lang.RT.contains (RT.java:724) => (contains? "aaa" 'a) IllegalArgumentException contains? not supported on type: java.lang.String clojure.lang.RT.contains (RT.java:724) Where it's almost as what I'd want for vector to be, namely: the valid keys numbers, are allowed, but when invalid keys are used ie. symbol or other strings, then exception is thrown; but not so for vectors; Granted that the exception thrown seems to be saying something other than: bad key type for passed collection (or so) but still... => (contains? [1 3 4] 2) true => (contains? [1 3 4] '2) true => (contains? [1 3 4] "2") false So if you were to use this generically on any collection, you'd maybe expect it to throw for vector as it does for string collection. Thanks for replying, Michael. On Fri, Mar 1, 2013 at 6:03 PM, Michael Gardner wrote: > On Feb 28, 2013, at 17:17 , AtKaaZ wrote: > > > According to this, can a vector have keys that are not numbers? like :a > , if not, then wouldn't it make more sense that > > (contains? [:a :b :c] :a) would throw ? It's probably just me. > > This is a reasonable point, and one I haven't seen made before. The only > problem I can see with throwing an exception is that one might sometimes > wish to deal with associative containers in a generic fashion, and thus end > up asking a vector if it contains a keyword or a string without doing so > explicitly. In that case you'd not want it to throw an exception any more > than the other associative collection types would. > > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- Please correct me if I'm wrong or incomplete, even if you think I'll subconsciously hate it. -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
On Feb 28, 2013, at 17:17 , AtKaaZ wrote: > According to this, can a vector have keys that are not numbers? like :a , if > not, then wouldn't it make more sense that > (contains? [:a :b :c] :a) would throw ? It's probably just me. This is a reasonable point, and one I haven't seen made before. The only problem I can see with throwing an exception is that one might sometimes wish to deal with associative containers in a generic fashion, and thus end up asking a vector if it contains a keyword or a string without doing so explicitly. In that case you'd not want it to throw an exception any more than the other associative collection types would. -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
Irakli Gozalishvili writes: > Maybe something else can be considered like `includes?` to do that > instead ? Also Rich says no better name was suggest for includes?, I > think `has?` would have being a lot better name. Don't know if it > makes sense to reply to that post at this point. I think member? is a rather good name: (defn member? "Returns true iff `e` is a member of `coll`." [e ^java.util.Collection coll] (if (seq coll) (.contains coll e) false)) Bye, Tassilo -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
Thanks Michael, This links are helpful. As far as I can see nothing like contains-val? or seq-contains? has being added though :( I'm trying to use cljs for performance sensitive code and high order functions like `some` don't really do it, while indexOf on strings in JS are well optimised by engines. Maybe something else can be considered like `includes?` to do that instead ? Also Rich says no better name was suggest for includes?, I think `has?` would have being a lot better name. Don't know if it makes sense to reply to that post at this point. Regards -- Irakli Gozalishvili Web: http://www.jeditoolkit.com/ On Thursday, 2013-02-28 at 14:59 , Michael Gardner wrote: > This is a sore spot that has been discussed many times on this list[1]. The > short version is that many people agree that the name "contains?" is > misleading to newcomers, but according to Rich it's not changing any time > soon[2]. What you want for linear searches is 'some (as mentioned in the doc > for 'contains?). > > Also, why are you quoting your vectors (e.g. '[:a :b :c] instead of just [:a > :b :c])? > > [1] Most recently, > https://groups.google.com/d/msg/clojure/wNFdG11zMMo/OC9ezSn9nRAJ > [2] https://groups.google.com/d/msg/clojure/bSrSb61u-_8/3-wjAkJ4VJgJ > > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > (mailto:clojure@googlegroups.com) > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > (mailto:clojure+unsubscr...@googlegroups.com) > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com > (mailto:clojure+unsubscr...@googlegroups.com). > For more options, visit https://groups.google.com/groups/opt_out. > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
On Thu, Feb 28, 2013 at 11:59 PM, Michael Gardner wrote: > This is a sore spot that has been discussed many times on this list[1]. > The short version is that many people agree that the name "contains?" is > misleading to newcomers, but according to Rich it's not changing any time > soon[2]. What you want for linear searches is 'some (as mentioned in the > doc for 'contains?). > > Also, why are you quoting your vectors (e.g. '[:a :b :c] instead of just > [:a :b :c])? > I accidentally quoted those in my repl tries and I ended up recalling the last variant (Ctrl+Up in repl) when I tried the 1 3 2 params. > > [1] Most recently, > https://groups.google.com/d/msg/clojure/wNFdG11zMMo/OC9ezSn9nRAJ > [2] https://groups.google.com/d/msg/clojure/bSrSb61u-_8/3-wjAkJ4VJgJ > Thank you for the links Michael. " Ambrose Bonnaire-Sergeant 9/3/12 'contains?' tests if a key is in a collection. Vector is an associative data structure, with keys being indexes. A vector of length 3 has the key 2, but not key 3. " According to this, can a vector have keys that are not numbers? like :a , if not, then wouldn't it make more sense that (contains? [:a :b :c] :a) would throw ? It's probably just me. Thanks. > > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- Please correct me if I'm wrong or incomplete, even if you think I'll subconsciously hate it. -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
This is a sore spot that has been discussed many times on this list[1]. The short version is that many people agree that the name "contains?" is misleading to newcomers, but according to Rich it's not changing any time soon[2]. What you want for linear searches is 'some (as mentioned in the doc for 'contains?). Also, why are you quoting your vectors (e.g. '[:a :b :c] instead of just [:a :b :c])? [1] Most recently, https://groups.google.com/d/msg/clojure/wNFdG11zMMo/OC9ezSn9nRAJ [2] https://groups.google.com/d/msg/clojure/bSrSb61u-_8/3-wjAkJ4VJgJ -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: contains? for vectors
by errors I mean bugs
On Thu, Feb 28, 2013 at 11:43 PM, AtKaaZ wrote:
>
>
>
> On Thu, Feb 28, 2013 at 11:23 PM, AtKaaZ wrote:
>
>> => *(contains? '(1 2 3) 1)*
>> IllegalArgumentException contains? not supported on type:
>> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>>
>> => **clojure-version**
>> {:major 1, :minor 5, :incremental 0, :qualifier "RC17"}
>>
>>
>> => *(contains? "foo" "o")*
>> IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>>
>> => *(contains? [:a :b :c] :a)*
>> false
>>
>> whoops
>>
>> contains? clojure.core
>>
>> Argument Lists:
>> [coll key]
>>
>> Documentation:
>> Returns true if key is present in the given collection, otherwise
>> returns false. Note that for numerically indexed collections like
>> vectors and Java arrays, this tests if the numeric key is within the
>> range of indexes. 'contains?' operates constant or logarithmic
>>time;
>> it will not perform a linear search for a value. See also 'some'.
>>
>> => (contains? '[:a :b :c] 1)
>> true
>> => (contains? '[:a :b :c] 3)
>> false
>> => (contains? '[:a :b :c] 2)
>> true
>>
>> well, I would not have expected that
>>
>> the code for that is this:
> clojure.lang.APersistentVector.containsKey(Object)
>
> public boolean containsKey(Object key){
> if(!(Util.isInteger(key)))
> return false;
> int i = ((Number) key).intValue();
> return i >= 0 && i < count();
> }
>
> if you ask me, it should throw rather than return false, that is, if
> anyone cares about not introducing subtle errors easily
>
>>
>> On Thu, Feb 28, 2013 at 11:14 PM, Irakli Gozalishvili
>> wrote:
>>
>>> Hi,
>>>
>>> Function
>>> contains?
>>> returns
>>> true if key is present in the given collection, although arguably on some
>>> data structures
>>> one would expect behaviour to be different. In fact it's already
>>> different on sets:
>>>
>>> (contains? #{:a :b :c} :a) ; => true
>>>
>>> Would that be reasonable to change behaviour for other types too like:
>>>
>>> (contains? [:a :b :c] :a) ; => false
>>> (contains? "foo" "o") ; => false
>>> (contains? '(1 2 3) 1) ; => false
>>>
>>> So they do return `true` instead ?
>>>
>>> If that will break too much code, maybe some other function can be added
>>> instead ?
>>>
>>> Regards
>>> --
>>> Irakli Gozalishvili
>>> Web: http://www.jeditoolkit.com/
>>>
>>> --
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "Clojure" group.
>>> To post to this group, send email to clojure@googlegroups.com
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>>> your first post.
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>>> clojure+unsubscr...@googlegroups.com
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>>> http://groups.google.com/group/clojure?hl=en
>>> ---
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>>> Groups "Clojure" group.
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>>>
>>>
>>>
>>
>>
>>
>> --
>> Please correct me if I'm wrong or incomplete,
>> even if you think I'll subconsciously hate it.
>>
>>
>
>
> --
> Please correct me if I'm wrong or incomplete,
> even if you think I'll subconsciously hate it.
>
>
--
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Re: contains? for vectors
On Thu, Feb 28, 2013 at 11:23 PM, AtKaaZ wrote:
> => *(contains? '(1 2 3) 1)*
> IllegalArgumentException contains? not supported on type:
> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>
> => **clojure-version**
> {:major 1, :minor 5, :incremental 0, :qualifier "RC17"}
>
>
> => *(contains? "foo" "o")*
> IllegalArgumentException contains? not supported on type:
> java.lang.String clojure.lang.RT.contains (RT.java:724)
>
> => *(contains? [:a :b :c] :a)*
> false
>
> whoops
>
> contains? clojure.core
>
> Argument Lists:
> [coll key]
>
> Documentation:
> Returns true if key is present in the given collection, otherwise
> returns false. Note that for numerically indexed collections like
> vectors and Java arrays, this tests if the numeric key is within the
> range of indexes. 'contains?' operates constant or logarithmic
>time;
> it will not perform a linear search for a value. See also 'some'.
>
> => (contains? '[:a :b :c] 1)
> true
> => (contains? '[:a :b :c] 3)
> false
> => (contains? '[:a :b :c] 2)
> true
>
> well, I would not have expected that
>
> the code for that is this:
clojure.lang.APersistentVector.containsKey(Object)
public boolean containsKey(Object key){
if(!(Util.isInteger(key)))
return false;
int i = ((Number) key).intValue();
return i >= 0 && i < count();
}
if you ask me, it should throw rather than return false, that is, if anyone
cares about not introducing subtle errors easily
>
> On Thu, Feb 28, 2013 at 11:14 PM, Irakli Gozalishvili wrote:
>
>> Hi,
>>
>> Function
>> contains?
>> returns
>> true if key is present in the given collection, although arguably on some
>> data structures
>> one would expect behaviour to be different. In fact it's already
>> different on sets:
>>
>> (contains? #{:a :b :c} :a) ; => true
>>
>> Would that be reasonable to change behaviour for other types too like:
>>
>> (contains? [:a :b :c] :a) ; => false
>> (contains? "foo" "o") ; => false
>> (contains? '(1 2 3) 1) ; => false
>>
>> So they do return `true` instead ?
>>
>> If that will break too much code, maybe some other function can be added
>> instead ?
>>
>> Regards
>> --
>> Irakli Gozalishvili
>> Web: http://www.jeditoolkit.com/
>>
>> --
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
>> To post to this group, send email to clojure@googlegroups.com
>> Note that posts from new members are moderated - please be patient with
>> your first post.
>> To unsubscribe from this group, send email to
>> clojure+unsubscr...@googlegroups.com
>> For more options, visit this group at
>> http://groups.google.com/group/clojure?hl=en
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "Clojure" group.
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>> email to clojure+unsubscr...@googlegroups.com.
>> For more options, visit https://groups.google.com/groups/opt_out.
>>
>>
>>
>
>
>
> --
> Please correct me if I'm wrong or incomplete,
> even if you think I'll subconsciously hate it.
>
>
--
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Re: contains? for vectors
=> *(contains? '(1 2 3) 1)*
IllegalArgumentException contains? not supported on type:
clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
=> **clojure-version**
{:major 1, :minor 5, :incremental 0, :qualifier "RC17"}
=> *(contains? "foo" "o")*
IllegalArgumentException contains? not supported on type: java.lang.String
clojure.lang.RT.contains (RT.java:724)
=> *(contains? [:a :b :c] :a)*
false
whoops
contains? clojure.core
Argument Lists:
[coll key]
Documentation:
Returns true if key is present in the given collection, otherwise
returns false. Note that for numerically indexed collections like
vectors and Java arrays, this tests if the numeric key is within the
range of indexes. 'contains?' operates constant or logarithmic
time;
it will not perform a linear search for a value. See also 'some'.
=> (contains? '[:a :b :c] 1)
true
=> (contains? '[:a :b :c] 3)
false
=> (contains? '[:a :b :c] 2)
true
well, I would not have expected that
On Thu, Feb 28, 2013 at 11:14 PM, Irakli Gozalishvili wrote:
> Hi,
>
> Function
> contains? returns
> true if key is present in the given collection, although arguably on some
> data structures
> one would expect behaviour to be different. In fact it's already different
> on sets:
>
> (contains? #{:a :b :c} :a) ; => true
>
> Would that be reasonable to change behaviour for other types too like:
>
> (contains? [:a :b :c] :a) ; => false
> (contains? "foo" "o") ; => false
> (contains? '(1 2 3) 1) ; => false
>
> So they do return `true` instead ?
>
> If that will break too much code, maybe some other function can be added
> instead ?
>
> Regards
> --
> Irakli Gozalishvili
> Web: http://www.jeditoolkit.com/
>
> --
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to clojure@googlegroups.com
> Note that posts from new members are moderated - please be patient with
> your first post.
> To unsubscribe from this group, send email to
> clojure+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/clojure?hl=en
> ---
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>
>
>
--
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contains? for vectors
Hi,
Function contains?
(http://clojuredocs.org/clojure_core/clojure.core/contains_q) returns true if
key is present in the given collection, although arguably on some data
structures
one would expect behaviour to be different. In fact it's already different on
sets:
(contains? #{:a :b :c} :a) ; => true
Would that be reasonable to change behaviour for other types too like:
(contains? [:a :b :c] :a) ; => false
(contains? "foo" "o") ; => false
(contains? '(1 2 3) 1) ; => false
So they do return `true` instead ?
If that will break too much code, maybe some other function can be added
instead ?
Regards
--
Irakli Gozalishvili
Web: http://www.jeditoolkit.com/
--
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