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Set on Attribute

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Sean P. DeNigris

Set on Attribute

Administrator

Say I have a collection like #('ab' 'ac' 'ba' bc') and I want to condense it so that a certain attribute is unique. In this example, say the first character, so I want one object where the first character is $a and one $b, but I don't care which object i.e. 'ab' or 'ac' for $a, but not both.

Is there an elegant way to do that?

Cheers,
Sean

Sven Van Caekenberghe-2

Re: Set on Attribute

PluggableSet ?

> On 26 Aug 2016, at 01:42, Sean P. DeNigris <[hidden email]> wrote:
>
> Say I have a collection like #('ab' 'ac' 'ba' bc') and I want to condense it
> so that a certain attribute is unique. In this example, say the first
> character, so I want one object where the first character is $a and one $b,
> but I don't care which object i.e. 'ab' or 'ac' for $a, but not both.
>
> Is there an elegant way to do that?
>
>
>
> -----
> Cheers,
> Sean
> --
> View this message in context: http://forum.world.st/Set-on-Attribute-tp4912672.html
> Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
>

monty-3

Re: Set on Attribute

In reply to this post by Sean P. DeNigris

Other than PluggableSet, something like Unix's sort and uniq combo would work:

condenseOnFirst: aCollection
| lastSelected |

^ aCollection sorted select: [:each |
(lastSelected isNil
or: [lastSelected first ~= each first])
ifTrue: [
lastSelected := each.
true]
ifFalse: [false]]

> Sent: Thursday, August 25, 2016 at 7:42 PM
> From: "Sean P. DeNigris" <[hidden email]>
> To: [hidden email]
> Subject: [Pharo-users] Set on Attribute
>
> Say I have a collection like #('ab' 'ac' 'ba' bc') and I want to condense it
> so that a certain attribute is unique. In this example, say the first
> character, so I want one object where the first character is $a and one $b,
> but I don't care which object i.e. 'ab' or 'ac' for $a, but not both.
>
> Is there an elegant way to do that?
>
>
>
> -----
> Cheers,
> Sean
> --
> View this message in context: http://forum.world.st/Set-on-Attribute-tp4912672.html
> Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
>
>

Sean P. DeNigris

Re: Set on Attribute

Administrator

In reply to this post by Sven Van Caekenberghe-2

Sven Van Caekenberghe-2 wrote

PluggableSet ?

Perfect! Thanks :)

My actual usage, in case anyone finds it helpful, was removing duplicate files:
uniqueFiles := PluggableSet new
equalBlock: [ :a :b | a isMD5Equal: b ];
hashBlock: [ :f | f binaryReadStreamDo: [ :str | (MD5 hashStream: str) hex hash ] ]
yourself.
allFiles := folder filesMatching: '*.eml'.
uniqueFiles addAll: allFiles.
(allFiles difference: uniqueFiles) do: #delete.

Cheers,
Sean