Clear a Flex ActionScript Dictionary

Question

Is it possible to clear a Flex flash.utils.Dictionary? I have a Dictionary that I want to clear (remove all elements).

score 6 · Accepted Answer · answered Mar 10 '10 at 17:49

6

I don't believe there is an explicit clear command.

However, you could write your own that would loop through all the keys and run this

delete dict[key];

Or you can just reassign

dict = new  Dictionary()

answered Mar 10 '10 at 17:49

Jason

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My goal was reuse the `Dictionary` instead of creating a new one. – Steve Kuo Mar 07 '13 at 20:40

score 6 · Answer 2 · edited Jan 15 '14 at 19:15

6

I think this will work, but I'm not 100% sure, as you're modifying the dictionary while iterating over it:

function clear(d:Dictionary):void {
  for(var id:* in d) {
    delete d[id];
  }
}

However, I generally just create a new Dictionary whenever I need to clear one (though if it's referenced in multiple places then that might not work for you).

edited Jan 15 '14 at 19:15

Triynko

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answered Mar 10 '10 at 18:10

Herms

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2

+1 works. tested it by running through twice, it was empty after first run. – Max Dohme Apr 03 '11 at 01:05
2

The code above has a defect : 'id' must be of NO type, since a Dictionary can hold any type of object as a key reference and not just a string like dynamic Objects do. The code above would ONLY delete string references! – Bill Kotsias Mar 09 '12 at 17:58
I edited the answer to fix the defect. id is now untyped (*), so it can take on any type and clear all possible keys. When it was typed as a string, id would only clear string keys; furthermore, no errors are thrown, and id is not null for non-string keys, they are simply skipped during the iteration. So id must be untyped to iterate over all possible keys. – Triynko Jan 15 '14 at 19:23

score 2 · Answer 3 · answered May 15 '14 at 18:25

To remove all the elements in the Dictionary, loop through each key and use the delete keyword

function clear(dict:Dictionary):void
{    
  for(var key:Object in dict) 
  {
        delete dict[key];
  }
}

If you want to be 100% sure that your deleted keys are garbage collected, you must replace your Dictionary instance with a new Dictionary.

dict = new Dictionary();

I once had a Dictionary object with 3 million Strings as keys. Those Strings would only be garbage collected when the Dictionary instance itself was.

David Dumke · Answer 4 · 2012-03-27T10:37:49.317

Not only do you need to make sure the key is of type object or * you need to get the keys first then delete them from the dictionary. Otherwise you will end up one key left in the dictionary(the last one).

I remember the above code working before but recently that has changed with the last iteration of flash player.

This code will ensure they are all removed including the last one.

//Clean up the dictionary
var keys:Array = [];
var key:*;
for ( var key:* in dictionary )
    keys.push( key );
for each ( var key:* in keys )
    delete dictionary[ key ];

score 0 · Answer 5 · edited Jan 16 '15 at 18:20

0

Just:

dictionary = new Dictionary()

edited Jan 16 '15 at 18:20

dario

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answered Jan 16 '15 at 17:55

dscfgos

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score 0 · Answer 6 · answered Dec 12 '16 at 11:29

0

public static function clear(dict:Dictionary):void {
        var key:*
        for(key in dict) {
            delete dict[key];
        }
    }

Use the above function as a utility function and you can use it throughout your code base.

answered Dec 12 '16 at 11:29

Rizwan_Khan

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Clear a Flex ActionScript Dictionary

6 Answers6