Convert List to Map

[gonzalad]

Hello,

I have the same question as http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E :

I need to do a lot of list-to-map conversions, and I'm looking for a way to
use commons collections for this.
I would like to do something like this:

Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
    void insertIntoMap(Object object, Map map) {
    SpecificObject s = (SpecificObject) object;
    map.put(s.getId(), s.getDescription());
    }
});

Is there a way to do that with commons collection ?

Thank you very much

[Ted Dunning]

How is this easier than this:

Map m = new HashMap();
for (SpecificObject x : list) {
    m.put(s.getId(), s.getDescription());
}

?

Why make this soo much harder than it needs to be?

On Wed, Jun 10, 2009 at 12:19 PM, Adrian Gonzalez <adr_gonzalez@...>wrote:

> Hello,
>
> I have the same question as
> http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E:
>
> I need to do a lot of list-to-map conversions, and I'm looking for a way to
> use commons collections for this.
> I would like to do something like this:
>
> Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
>    void insertIntoMap(Object object, Map map) {
>    SpecificObject s = (SpecificObject) object;
>    map.put(s.getId(), s.getDescription());
>    }
> });
>
> Is there a way to do that with commons collection ?
>
> Thank you very much
>
>
>

--
Ted Dunning, CTO
DeepDyve

111 West Evelyn Ave. Ste. 202
Sunnyvale, CA 94086
http://www.deepdyve.com
858-414-0013 (m)
408-773-0220 (fax)

[gonzalad]

Thanks

Your sample works fine for my use case (that's exactly what I'm doing in my code), but I was wondering about such utility thing just after looking at :
http://commons.apache.org/collections/api-release/org/apache/commons/collections/map/TransformedMap.html#decorate(java.util.Map,%20org.apache.commons.collections.Transformer,%20org.apache.commons.collections.Transformer)
which is a map-to-map conversions.

Since commons-collection provides map-to-map conversion, why does'nt it provide list-to-map conversion with the same logic ?





________________________________
De : Ted Dunning <ted.dunning@...>
À : Commons Users List <user@...>
Envoyé le : Jeudi, 11 Juin 2009, 23h12mn 10s
Objet : Re: Convert List to Map

How is this easier than this:

Map m = new HashMap();
for (SpecificObject x : list) {
    m.put(s.getId(), s.getDescription());
}

?

Why make this soo much harder than it needs to be?

On Wed, Jun 10, 2009 at 12:19 PM, Adrian Gonzalez <adr_gonzalez@...>wrote:

> Hello,
>
> I have the same question as
> http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E:
>
> I need to do a lot of list-to-map conversions, and I'm looking for a way to
> use commons collections for this.
> I would like to do something like this:
>
> Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
>    void insertIntoMap(Object object, Map map) {
>    SpecificObject s = (SpecificObject) object;
>    map.put(s.getId(), s.getDescription());
>    }
> });
>
> Is there a way to do that with commons collection ?
>
> Thank you very much
>
>
>

--
Ted Dunning, CTO
DeepDyve

111 West Evelyn Ave. Ste. 202
Sunnyvale, CA 94086
http://www.deepdyve.com
858-414-0013 (m)
408-773-0220 (fax)

[jwcarman]

We had a discussion of something like what you're asking for in the past:

http://mail-archives.apache.org/mod_mbox/commons-dev/200709.mbox/<f2e8eedf0709032030s1665dd5g36797577927d221c@...>


On Fri, Jun 12, 2009 at 10:55 AM, Adrian Gonzalez<adr_gonzalez@...> wrote:

> Thanks
>
> Your sample works fine for my use case (that's exactly what I'm doing in my code), but I was wondering about such utility thing just after looking at :
> http://commons.apache.org/collections/api-release/org/apache/commons/collections/map/TransformedMap.html#decorate(java.util.Map,%20org.apache.commons.collections.Transformer,%20org.apache.commons.collections.Transformer)
> which is a map-to-map conversions.
>
> Since commons-collection provides map-to-map conversion, why does'nt it provide list-to-map conversion with the same logic ?
>
>
>
>
>
> ________________________________
> De : Ted Dunning <ted.dunning@...>
> À : Commons Users List <user@...>
> Envoyé le : Jeudi, 11 Juin 2009, 23h12mn 10s
> Objet : Re: Convert List to Map
>
> How is this easier than this:
>
> Map m = new HashMap();
> for (SpecificObject x : list) {
>    m.put(s.getId(), s.getDescription());
> }
>
> ?
>
> Why make this soo much harder than it needs to be?
>
> On Wed, Jun 10, 2009 at 12:19 PM, Adrian Gonzalez <adr_gonzalez@...>wrote:
>
>> Hello,
>>
>> I have the same question as
>> http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E:
>>
>> I need to do a lot of list-to-map conversions, and I'm looking for a way to
>> use commons collections for this.
>> I would like to do something like this:
>>
>> Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
>>    void insertIntoMap(Object object, Map map) {
>>    SpecificObject s = (SpecificObject) object;
>>    map.put(s.getId(), s.getDescription());
>>    }
>> });
>>
>> Is there a way to do that with commons collection ?
>>
>> Thank you very much
>>
>>
>>
>
>
>
>
> --
> Ted Dunning, CTO
> DeepDyve
>
> 111 West Evelyn Ave. Ste. 202
> Sunnyvale, CA 94086
> http://www.deepdyve.com
> 858-414-0013 (m)
> 408-773-0220 (fax)
>
>
>
>

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[gonzalad]

That's exactly what I was talking about !

Has it done its way to commons collection ? (I don't see it in 3.2.1 or in JIRA)

Code extract from http://mail-archives.apache.org/mod_mbox/commons-dev/200709.mbox/<f2e8eedf0709032030s1665dd5g36797577927d221c@...> :

Map<K,V> CollectionUtils.toMap(Collection<C> input,
Transformer<C,K> keyTransformer, Transformer<C,V>
valueTransformer, Map<K,V> map)
or
Map<K,V> CollectionUtils.toMap(Collection<C> input,
Transformer<C,K> keyTransformer, Transformer<C,V>
valueTransformer)







________________________________
De : James Carman <james@...>
À : Commons Users List <user@...>
Envoyé le : Vendredi, 12 Juin 2009, 17h27mn 03s
Objet : Re: Re : Convert List to Map

We had a discussion of something like what you're asking for in the past:

http://mail-archives.apache.org/mod_mbox/commons-dev/200709.mbox/<f2e8eedf0709032030s1665dd5g36797577927d221c@...>


On Fri, Jun 12, 2009 at 10:55 AM, Adrian Gonzalez<adr_gonzalez@...> wrote:

> Thanks
>
> Your sample works fine for my use case (that's exactly what I'm doing in my code), but I was wondering about such utility thing just after looking at :
> http://commons.apache.org/collections/api-release/org/apache/commons/collections/map/TransformedMap.html#decorate(java.util.Map,%20org.apache.commons.collections.Transformer,%20org.apache.commons.collections.Transformer)
> which is a map-to-map conversions.
>
> Since commons-collection provides map-to-map conversion, why does'nt it provide list-to-map conversion with the same logic ?
>
>
>
>
>
> ________________________________
> De : Ted Dunning <ted.dunning@...>
> À : Commons Users List <user@...>
> Envoyé le : Jeudi, 11 Juin 2009, 23h12mn 10s
> Objet : Re: Convert List to Map
>
> How is this easier than this:
>
> Map m = new HashMap();
> for (SpecificObject x : list) {
>    m.put(s.getId(), s.getDescription());
> }
>
> ?
>
> Why make this soo much harder than it needs to be?
>
> On Wed, Jun 10, 2009 at 12:19 PM, Adrian Gonzalez <adr_gonzalez@...>wrote:
>
>> Hello,
>>
>> I have the same question as
>> http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E:
>>
>> I need to do a lot of list-to-map conversions, and I'm looking for a way to
>> use commons collections for this.
>> I would like to do something like this:
>>
>> Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
>>    void insertIntoMap(Object object, Map map) {
>>    SpecificObject s = (SpecificObject) object;
>>    map.put(s.getId(), s.getDescription());
>>    }
>> });
>>
>> Is there a way to do that with commons collection ?
>>
>> Thank you very much
>>
>>
>>
>
>
>
>
> --
> Ted Dunning, CTO
> DeepDyve
>
> 111 West Evelyn Ave. Ste. 202
> Sunnyvale, CA 94086
> http://www.deepdyve.com
> 858-414-0013 (m)
> 408-773-0220 (fax)
>
>
>
>

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[jwcarman]

I don't think so, but you're free to copy it if you wish.  There's
really not much code there.

On Fri, Jun 12, 2009 at 5:56 PM, Adrian Gonzalez<adr_gonzalez@...> wrote:

> That's exactly what I was talking about !
>
> Has it done its way to commons collection ? (I don't see it in 3.2.1 or in JIRA)
>
> Code extract from http://mail-archives.apache.org/mod_mbox/commons-dev/200709.mbox/<f2e8eedf0709032030s1665dd5g36797577927d221c@...> :
>
> Map<K,V> CollectionUtils.toMap(Collection<C> input,
> Transformer<C,K> keyTransformer, Transformer<C,V>
> valueTransformer, Map<K,V> map)
> or
> Map<K,V> CollectionUtils.toMap(Collection<C> input,
> Transformer<C,K> keyTransformer, Transformer<C,V>
> valueTransformer)
>
>
>
>
>
>
>
> ________________________________
> De : James Carman <james@...>
> À : Commons Users List <user@...>
> Envoyé le : Vendredi, 12 Juin 2009, 17h27mn 03s
> Objet : Re: Re : Convert List to Map
>
> We had a discussion of something like what you're asking for in the past:
>
> http://mail-archives.apache.org/mod_mbox/commons-dev/200709.mbox/<f2e8eedf0709032030s1665dd5g36797577927d221c@...>
>
>
> On Fri, Jun 12, 2009 at 10:55 AM, Adrian Gonzalez<adr_gonzalez@...> wrote:
>> Thanks
>>
>> Your sample works fine for my use case (that's exactly what I'm doing in my code), but I was wondering about such utility thing just after looking at :
>> http://commons.apache.org/collections/api-release/org/apache/commons/collections/map/TransformedMap.html#decorate(java.util.Map,%20org.apache.commons.collections.Transformer,%20org.apache.commons.collections.Transformer)
>> which is a map-to-map conversions.
>>
>> Since commons-collection provides map-to-map conversion, why does'nt it provide list-to-map conversion with the same logic ?
>>
>>
>>
>>
>>
>> ________________________________
>> De : Ted Dunning <ted.dunning@...>
>> À : Commons Users List <user@...>
>> Envoyé le : Jeudi, 11 Juin 2009, 23h12mn 10s
>> Objet : Re: Convert List to Map
>>
>> How is this easier than this:
>>
>> Map m = new HashMap();
>> for (SpecificObject x : list) {
>>    m.put(s.getId(), s.getDescription());
>> }
>>
>> ?
>>
>> Why make this soo much harder than it needs to be?
>>
>> On Wed, Jun 10, 2009 at 12:19 PM, Adrian Gonzalez <adr_gonzalez@...>wrote:
>>
>>> Hello,
>>>
>>> I have the same question as
>>> http://mail-archives.apache.org/mod_mbox/commons-user/200509.mbox/%3C878e7290050905002752ed543d@...%3E:
>>>
>>> I need to do a lot of list-to-map conversions, and I'm looking for a way to
>>> use commons collections for this.
>>> I would like to do something like this:
>>>
>>> Map map = ListUtils.toMap(list, new SomeTransformerInterface() {
>>>    void insertIntoMap(Object object, Map map) {
>>>    SpecificObject s = (SpecificObject) object;
>>>    map.put(s.getId(), s.getDescription());
>>>    }
>>> });
>>>
>>> Is there a way to do that with commons collection ?
>>>
>>> Thank you very much
>>>
>>>
>>>
>>
>>
>>
>>
>> --
>> Ted Dunning, CTO
>> DeepDyve
>>
>> 111 West Evelyn Ave. Ste. 202
>> Sunnyvale, CA 94086
>> http://www.deepdyve.com
>> 858-414-0013 (m)
>> 408-773-0220 (fax)
>>
>>
>>
>>
>
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> To unsubscribe, e-mail: user-unsubscribe@...
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>
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