[RESOLVED] Array Initialization problem

@JMRKERAug 29.2009

The following does not initialize correctly.
It errors on the first “mainArray[0] = new mainObj” indicating a missing ‘;’ in the statement.

What am I doing wrong?

[code] <html> <head> <title> Array Association </title> <script type=”text/javascript”> var mainObj = { nameinfo : ”, hatsize : ”, necksize : ”, armlength : ”, chest : ”, waist : ”, hips : ”, leglength : ”, shoesize : ” }; var mainArray = []; mainArray[0] = new mainObj { nameinfo:’John’, hatsize:’6′, necksize:’14’, armlength:’28’, chest:’42’, waist:’30’, hips:’34’, leglength:’28’, shoesize:’10’ }; mainArray[1] = new mainObj { nameinfo:’Jacob’, hatsize:’6.5′, necksize:’15’, armlength:’30’, chest:’44’, waist:’32’, hips:’36’, leglength:’32’, shoesize:’11’ }; mainArray[2] = new mainObj { nameinfo:’Jingle’, hatsize:’7.5′, necksize:’16’, armlength:’32’, chest:’42’, waist:’36’, hips:’38’, leglength:’36’, shoesize:’12’ }; mainArray[3] = new mainObj { nameinfo:’Heimer’, hatsize:’6.25′, necksize:’14.5′, armlength:’33’, chest:’40’, waist:’33’, hips:’34’, leglength:’38’, shoesize:’11.5′ }; mainArray[4] = new mainObj { nameinfo:’Smith’, hatsize:’6.25′, necksize:’17’, armlength:’34’, chest:’50’, waist:’44’, hips:’46’, leglength:’30’, shoesize:’10.5′ }; </script> </head> <body> <script type=”text/javascript”> var str = ‘<table border=”1″>’; for (var i=0; i<mainArray.length; i++) { str += ‘<tr>’; str += ‘<td>’+mainArray[i].nameinfo+'</td>’ str += ‘<td>’+mainArray[i].shoesize+'</td>’ str += ‘</tr>’; } str += ‘</table>’; document.write(str); </script> </body> </html> [/code]

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6 Comments(s) _↴

@mrhooAug 29.2009 — #mainObj is not a constructor, and cannot initialize an instance.

If it was, you would need to include parenthesis around the new instance parameter.

You can assign to each array item an object-

[CODE]var mainArray= [];
 mainArray[0]={
 nameinfo: 'John', hatsize: '6', necksize: '14', armlength: '28',
 chest: '42', waist: '30', hips: '34', leglength: '28', shoesize: '10'
 };[/CODE]

//Or make a mainObj constructor function-

[CODE]
 var mainArray= [];
 function mainObj(obj){
 for(var p in obj) this[p]= obj[p];
 }
 
 mainArray[0]= new mainObj({
 nameinfo: 'John', hatsize: '6', necksize: '14', armlength: '28',
 chest: '42', waist: '30', hips: '34', leglength: '28', shoesize: '10'
 });[/CODE]

@scragarAug 29.2009 — #The array is not your problem. It's you use of an object as a class(Which javascript doesn't really have, meaning you have to use a function as if it was a class).

[code=php]
 function mainObj(atr){
 for(var i in atr){
 this[i] = atr[i];
 }
 }
 
 var mainArray = [];
 mainArray[0] = new mainObj({ nameinfo:'John', hatsize:'6', necksize:'14', armlength:'28',
 chest:'42', waist:'30', hips:'34', leglength:'28', shoesize:'10' });
 
 [/code]

Give that a run.

@JMRKERauthorAug 29.2009 — #Thank you 'mrhoo' and 'scragar'.

The object creation technique works fine.

I have another question, but I'm going to play with what you have given me

to see if I can solve it myself.

Appreciate the insight!

@JMRKERauthorAug 29.2009 — #Question:

In this test script, is this the best way to initialize the contents of the 'mainArray'?

I'm assuming the contents of 'ArrayInfo' could also be obtained from a text file, external JS or AJAX read function.

It appears to work fine in FF (have not experimented with MSIE yet)

but I'm still trying to get my head around objects vs. arrays and how to manipulate them. ?

<i>
 </i>&lt;html&gt;
 &lt;head&gt;
 &lt;title&gt; Array Association &lt;/title&gt;
 &lt;script type="text/javascript"&gt;
 // From: http://www.webdeveloper.com/forum/showthread.php?p=1031767#post1031767
 /* 'mrhoo' and 'scragar' suggestions */
 
 var mainArray = [];
 function mainObj(obj) {	for (var p in obj) this[p] = obj[p]; }
 
 
 /*  information obtained from external text source   */ 
 
 var ArrayInfo = [ // name, hatsize, necksize, armlength, chest, waist, hips, leglength, shoesize
 ['John',   '6',    '14',   '28', '42', '30', '34', '28', '10'], 
 ['Jacob',  '6.5',  '15',   '30', '44', '32', '36', '32', '11'], 
 ['Jingle', '7.5',  '16',   '32', '42', '36', '38', '36', '12'], 
 ['Heimer', '6.25', '14.5', '33', '40', '33', '34', '38', '11.5'], 
 ['Smith',  '6.25', '17',   '34', '50', '44', '46', '30', '10.5'] 
 ];
 
 function SetupRec(i) {
 mainArray[i] = new mainObj({nameinfo:'',hatsize:'',necksize:'',armlength:'',
 chest:'',waist:'',hips:'',leglength:'',shoesize:''});
 mainArray[i].nameinfo = ArrayInfo[i][0];
 mainArray[i].hatsize = ArrayInfo[i][1];
 mainArray[i].necksize = ArrayInfo[i][2];
 mainArray[i].armlength = ArrayInfo[i][3];
 mainArray[i].chest = ArrayInfo[i][4];
 mainArray[i].waist = ArrayInfo[i][5];
 mainArray[i].hips = ArrayInfo[i][6];
 mainArray[i].leglength = ArrayInfo[i][7];
 mainArray[i].shoesize = ArrayInfo[i][8];
 }
 
 function mainArrayInitialization() {
 for (var i=0; i&lt;ArrayInfo.length; i++) { SetupRec(i); }
 }
 onload = mainArrayInitialization();
 /* */
 
 &lt;/script&gt;
 &lt;/head&gt;
 &lt;body&gt;
 &lt;script type="text/javascript"&gt;
 var str = '&lt;table border="1"&gt;';
 str += '&lt;tr&gt;&lt;td colspan="9"&gt;Array size: '+mainArray.length+'&lt;/td&gt;&lt;/tr&gt;';
 for (var i=0; i&lt;mainArray.length; i++) {
 str += '&lt;tr&gt;';
 str += '&lt;td&gt;'+mainArray[i].nameinfo+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].hatsize+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].necksize+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].armlength+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].chest+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].waist+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].hips+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].leglength+'&lt;/td&gt;'  <br/>
 str += '&lt;td&gt;'+mainArray[i].shoesize+'&lt;/td&gt;'  <br/>
 str += '&lt;/tr&gt;';
 }
 str += '&lt;/table&gt;';
 document.write(str);
 &lt;/script&gt;
 &lt;/body&gt;
 &lt;/html&gt;

@mrhooAug 29.2009 — #There is nothing at all wrong with your code,

but you [I]could [/I]create the new objects directly from their ordered arrays in the constructor.

[CODE]var mainArray= [];
 function mainObj(obj){
 if(obj.constructor== Array){
 var n= 0, fieldnames= ['naminfo','hatsize','necksize','armlength','chest','waist','hips','leglength','shoesize'];
 while(n < 9){
 this[fieldnames[n]]= obj[n];
 ++n;
 }
 }
 else{
 for(var p in obj) this[p]= obj[p];
 }
 }
 
 
 
 /* information obtained from external text source */
 var ArrayInfo= [//name, hatsize, necksize, armlength, chest, waist, hips, leglength, shoesize
 ['John','6','14','28','42','30','34','28','10'],
 ['Jacob','6.5','15','30','44','32','36','32','11'],
 ['Jingle','7.5','16','32','42','36','38','36','12'],
 ['Heimer','6.25','14.5','33','40','33','34','38','11.5'],
 ['Smith','6.25','17','34','50','44','46','30','10.5']
 ];
 function mainArrayInitialization(){
 for(var i= 0; i<ArrayInfo.length; i++){
 mainArray[i]= new mainObj(ArrayInfo[i]);
 }
 
 }[/CODE]

//test (with a toString method for reporting)

[CODE]mainObj.prototype.toString= function(){
 var A= [];
 for(var p in this){
 if(this.hasOwnProperty(p)) A.push(p+'= '+this[p]);
 }
 return A.join(', ');
 }[/CODE]

[B]mainArrayInitialization();

alert(mainArray.join('nn'));[/B]

@JMRKERauthorAug 29.2009 — #Thank you!

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