address array by variable variable

[mps]

Suppose.....
arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined' instead of
'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

Thanx in advance,
Marco Snoek

[Vincent van Beveren]

> Suppose.....

arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined' instead of
'only'...)

I think this is what you are looking for:

eval(ArrayVar+"[0]");

But you can also do the following

arr1 = Array("only", "a", "test");
arr2 = Array("only", "another", "test");

curArray = arr1;
alert(curArray[1]); // displays 'a';

curArray = arr2;
alert(curArray[1]); // displays 'another';

Which feels better.

Good luck,
Vincent

[Ivo]

"mp*@webmind.nl " wrote

arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined' instead of 'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

Not sure what you are trying to do. ArrayVar is a now string variable. If
you remove the quotes from your second line above, so it becomes

ArrayVar = arr;

then ArrayVar will be an array too, and ArrayVar[0] will be "only".
HTH
Ivo

[lallous]

Hello

"mp*@webmind.nl "
<*DONT*[mps]_YOU#DARE(SEND) SPAM@@[webmind]--TOME.[.nl]%%^.orgtext> wrote in
message news:40******** *************** @dreader5.news. xs4all.nl...

Suppose.....
arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined' instead of 'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

Yes, you can use eval() as other indicated or you can use something like:

<script>
var x;

array1 = new Array("hello", "world");

x = "array1";

alert(window[x][0]); // <-- hello

</script>
The variables are stored under the window object. You can also do something
like: window["array1"][N] ...

--
Elias

[Quarco]

That is my problem: trying to retrieve an array item with a string
variable-name..
You see, the more elaborate version of my problem is

an array with positions:
positions =
("liggend","sta and","staand"," liggend","staan d","staand","li ggend");

an array
liggend[0] = array("value1a" ,"value2a","val ue3a","value4a" ,"value5a");
liggend[1] = array("value1b" ,"value2b","val ue3b","value4b" ,"value5b");
....
staand[0] = array("value1c" ,"value2c","val ue3c","value4c" ,"value5c");
...etc..

Now:
getValue(3) { //For example...
ArrayVar = positions[3]; // in this example ArrayVar = liggend
for(anItem in ArrayVar) {
...... /// walk through the 'liggend-array'..
}
}

I believe the eval function from Vincent does the trick...
Marco

"Ivo" <[e-mail] > schreef in bericht
news:40******** *************** @news.wanadoo.n l...

"mp*@webmind.nl " wrote

arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined'

instead of

'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

Not sure what you are trying to do. ArrayVar is a now string variable. If
you remove the quotes from your second line above, so it becomes

ArrayVar = arr;

then ArrayVar will be an array too, and ArrayVar[0] will be "only".
HTH
Ivo

[Quarco]

Hey,

Great..
It works!!

Thanx all for your time!!

Regards,
Marco
"lallous" <la*****@lgwm.o rg> schreef in bericht
news:2m******** ****@uni-berlin.de...

Hello

"mp*@webmind.nl "
<*DONT*[mps]_YOU#DARE(SEND) SPAM@@[webmind]--TOME.[.nl]%%^.orgtext> wrote in message news:40******** *************** @dreader5.news. xs4all.nl...

Suppose.....
arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayVar[0]);

This the simplyfied version of my problem.. (alerting 'undefined'

instead of

'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

Yes, you can use eval() as other indicated or you can use something like:

<script>
var x;

array1 = new Array("hello", "world");

x = "array1";

alert(window[x][0]); // <-- hello

</script>
The variables are stored under the window object. You can also do

something like: window["array1"][N] ...

--
Elias

[Lee]

SEND said:

Suppose.....
arr = Array("only","a ","test");
ArrayVar = "arr";
alert(ArrayV ar[0]);

This the simplyfied version of my problem.. (alerting 'undefined' instead of
'only'...)

Now I use the most ugly workaround:
if(ArrayVar == "arr") { alert(arr[0]); }

But there has to be a much better solution?????

It depends on what you're really trying to do. If you just need
a way to use a variable name for an array, then you can use a
reference, instead of a string holding the name:

var myRef=arr;
alert(myRef[0]);

If you really need to use the string name, then there is probably
a better design that you could use, but one way to do it is:

var arrayGroup = { arr: [ "only", "a", "test" ],
brr: [ "a", "different" , "array" ],
crr: [ "one", "more", "example" ]
};
alert(arrayGrou p["arr"][0]);
You could also use eval(), but that is inefficient and difficult
to debug.

[Lasse Reichstein Nielsen]

"Quarco" <*DONT*[mps]_YOU#DARE(SEND) SPAM@@[webmind]--TOME.[.nl]%%^.orgtext> writes:

That is my problem: trying to retrieve an array item with a string
variable-name..
In my experience, you are using a wrong approach to solve the real problem.
I have never seen a case where it was necessary to address a variable
using a string containing its name. Whatever you are trying to do, I'll
almost guarantee I can find a better way to do it :)
an array with positions:
positions =
("liggend","sta and","staand"," liggend","staan d","staand","li ggend");

an array
liggend[0] = array("value1a" ,"value2a","val ue3a","value4a" ,"value5a");
liggend[1] = array("value1b" ,"value2b","val ue3b","value4b" ,"value5b");
...
staand[0] = array("value1c" ,"value2c","val ue3c","value4c" ,"value5c");
..etc..
Instead, do:

var c = new Object(); // container object
c.liggend = new Array();
c.staand = new Array();
and then
c.liggend[0] = ...
c.liggend[1] = ...
c.liggend[2] = ...
...
c.staand[0] = ...
c.staand[1] = ...
getValue(3) { //For example...
ArrayVar = positions[3]; // in this example ArrayVar = liggend
for(anItem in ArrayVar) {
function getValue(i) {
var arrayVar = positions[i];
var arr = c[arrayVar]
for(index in arr) {
var item = arr[index];
// ...
}
...
I believe the eval function from Vincent does the trick...
"eval" is almost never the best solution. It is inefficient and
errorprone, and should be left for the few cases where it can't be
avoided.
"Ivo" <[e-mail] > schreef in bericht
news:40******** *************** @news.wanadoo.n l...

Please don't top post.

Regards
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Lasse Reichstein Nielsen]

"Quarco" <*DONT*[mps]_YOU#DARE(SEND) SPAM@@[webmind]--TOME.[.nl]%%^.orgtext> writes:

On second thought, this solution is even prettier:

---
var liggend = [
["value1a","valu e2a","value3a", "value4a","valu e5a"],
["value1b","valu e2b","value3b", "value4b","valu e5b"],
...
];
var staand = [
["value1c","valu e2c","value3c", "value4c","valu e5c"],
...
];

var positions = [liggend, staand, staand, liggend, staand, staand, liggend];

function getValue(i) {
var arr = positions[i];
for (var index in arr) {
var item = arr[index];
...
}
...
---

Good luck.
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Quarco]

Hmmm ..

Think this is the 'ultimate' solution Lasse... :-)

Thanx a lot!

Marco

"Lasse Reichstein Nielsen" <lr*@hotpop.com > schreef in bericht
news:65******** **@hotpop.com.. .

"Quarco" <*DONT*[mps]_YOU#DARE(SEND) SPAM@@[webmind]--TOME.[.nl]%%^.orgtext> writes:
On second thought, this solution is even prettier:

---
var liggend = [
["value1a","valu e2a","value3a", "value4a","valu e5a"],
["value1b","valu e2b","value3b", "value4b","valu e5b"],
...
];
var staand = [
["value1c","valu e2c","value3c", "value4c","valu e5c"],
...
];

var positions = [liggend, staand, staand, liggend, staand, staand, liggend];
function getValue(i) {
var arr = positions[i];
for (var index in arr) {
var item = arr[index];
...
}
...
---

Good luck.
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html> 'Faith without judgement merely degrades the spirit divine.'