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iterate through an anonymous array?

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Join Date: Sep 2009

Posts: 11

Reputation: Ghodmode is an unknown quantity at this point

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Ghodmode

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iterate through an anonymous array?

Oct 11th, 2009

Is it possible to iterate through an anonymous array of strings with a for loop?

Here's what I'm trying to do:

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 JavaScript / DHTML / AJAX Syntax (Toggle Plain Text) 
for ( i in ['country', 'city', 'state'] ) {
    doSomethingWithString(i);
}
for ( i in ['country', 'city', 'state'] ) {
    doSomethingWithString(i);
}

What I want is the string, but what I'm getting is the index number of the array, which I can't use because the array isn't named.

Thank you.

--
-- Ghodmode

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Join Date: Apr 2005

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Reputation: ShawnCplus is a glorious beacon of light

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ShawnCplus ShawnCplus is offline

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Code Monkey

Oct 11th, 2009

No you can't. i in your scenario is the key for each value so the only way to get the actual value would to do ['val1', 'val2', 'val3'][i] which would defeat the purpose

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Join Date: Jun 2008

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Reputation: Troy III will become famous soon enough

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Troy III

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Posting Whiz

Oct 12th, 2009

•

Originally Posted by Ghodmode

Is it possible to iterate through an anonymous array of strings with a for loop?

Here's what I'm trying to do:
Help with Code Tags

JavaScript / DHTML / AJAX Syntax (Toggle Plain Text)
for ( i in ['country', 'city', 'state'] ) {
    doSomethingWithString(i);
}
for ( i in ['country', 'city', 'state'] ) { doSomethingWithString(i); }
What I want is the string, but what I'm getting is the index number of the array, which I can't use because the array isn't named.

Thank you.

--
-- Ghodmode

in fact, there is no such thing as anonymous array, this supposedly "arrray" will be garbage collected as soon as the function has passed over.

Therefore you must initiate/create that array before using it at least locally.

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 JavaScript / DHTML / AJAX Syntax (Toggle Plain Text) 
for ( i in o = ['country', 'city', 'state'] ){ 
	doSomethingWithString(o[i]);
}
for ( i in o = ['country', 'city', 'state'] ){ 
	doSomethingWithString(o[i]);
}

A more readable written form of the same with array value alert:

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 JavaScript / DHTML / AJAX Syntax (Toggle Plain Text) 
for ( value in option = ['country', 'city', 'state'] ){ 
	alert( option[ value ] )
}
for ( value in option = ['country', 'city', 'state'] ){ 
	alert( option[ value ] )
}

will serially alert:
country
city
state --- I believe this was what you were looking for.
Cheers.

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Join Date: Apr 2005

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Reputation: ShawnCplus is a glorious beacon of light

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ShawnCplus ShawnCplus is offline

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Code Monkey

Oct 12th, 2009

It should be noted, however, that you can hack around it by not using an array but using an object like so

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 javascript Syntax (Toggle Plain Text) 
for ( i in ['key1', 'key2'])
  alert(i); // 1, and 2 respectively
 
// BUT
 
for ( i in {key1:0, key2:0})
  alert(i); // key1, and key2 respectively
for ( i in ['key1', 'key2'])
  alert(i); // 1, and 2 respectively

// BUT

for ( i in {key1:0, key2:0})
  alert(i); // key1, and key2 respectively

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Join Date: Sep 2009

Posts: 11

Reputation: Ghodmode is an unknown quantity at this point

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Ghodmode

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garbage collection with JavaScript?

Oct 13th, 2009

Thanks to both ShawnCplus and Troy III. Troy's solution is what I was looking for, but using the object notation as Shawn did is an idea with potential, too.

I guess I used the wrong term when I called it an "anonymous array", but I'm glad you got the idea. I was talking about iterating through a list of strings that could be thrown away as soon as I was done going through the list.

This is the first time I've read the term "garbage collection" in the context of JavaScript. I usually only read it in reference to Java, where the process is incredibly well documented. If I think of the browser as the JavaScript equivalent of Java's "virtual machine", is it basically the same process?

Thank you.

--
-- Ghodmode

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Join Date: Jun 2008

Posts: 348

Reputation: Troy III will become famous soon enough

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Troy III

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Posting Whiz

Oct 13th, 2009

•

Originally Posted by Ghodmode

Thanks to both ShawnCplus and Troy III. Troy's solution is what I was looking for, but using the object notation as Shawn did is an idea with potential, too.

I guess I used the wrong term when I called it an "anonymous array", but I'm glad you got the idea. I was talking about iterating through a list of strings that could be thrown away as soon as I was done going through the list.

This is the first time I've read the term "garbage collection" in the context of JavaScript. I usually only read it in reference to Java, where the process is incredibly well documented. If I think of the browser as the JavaScript equivalent of Java's "virtual machine", is it basically the same process?

Thank you.

--
-- Ghodmode

No,
it is even better!
:')

That's why you never heard of it before.
This one is automatic and doesn't need coders assistance. There are very rare situations when a coder might begin to notice its leaks or his own misuse of objects and vars etc.