return functions for arrays_问答_开发者_运维开发者技术经验分享

Need a bit of help completing a Javascript program which uses succesive functions. I cant find a way of replacing the return statement with variable so I can use the varable in the second function.

The program uses the statement findArrayparts(myArray1, myArray2) to get the function findArrayparts(myArray1, myArray2) to generate a random integer one less then the array length of one of the arrays ( equal lengths).

This random integer is then used in the function findArrayparts(myArray1, myArray2) to work out the corresponding array elements and put them into an array which is the开发者_如何学Gon displayed in an alert box.

<SCRIPT SRC = glossary.js></SCRIPT>
<SCRIPT language = "JavaScript">
var myVar1;
var myVar2;
var myVar3;

var myArray1 = ['red', 'orange', 'green', 'blue', 'yellow'];
var myArray2 = ['tomatoe', 'orange', 'apples', 'blueberry', 'banana'];

// generates random integer and assigns result to myVar1
function getNumberRand(aNum)
   {
     //return Math.floor(Math.random() * aNum); 
     myVar1 =  Math.floor(Math.random() * aNum); 
   }

   function findArrayparts(myArray1, myArray2)    
    {   
// calls getNumberRand function         
      getNumberRand(myArray1.length); 

      // works out characters at same index in both arrays
      myVar2 = (myArray1(myVar1));
      myVar3 = (myArray2(myVar1)); 

      // new array to hold output
      outputArray = new Array(myVar2, myVar3);

        // display output
      outputArray.join();
        alert(outputArray); 
    }    

// Calls findArrayparts function        
    findArrayparts(myArray1, myArray2);


</SCRIPT>


</HEAD>
<BODY>
</BODY>
</HTML>

DEMO: http://jsfiddle.net/PjtxY/

var myArray1 = ['red', 'orange', 'green', 'blue', 'yellow'];
var myArray2 = ['tomatoe', 'orange', 'apples', 'blueberry', 'banana'];


function getNumberRand(aNum) {
    return Math.floor(Math.random() * aNum); 
}

function findArrayparts(myArray1, myArray2) {

        // Store return value in local variable   
    var random_num = getNumberRand(myArray1.length);

       // Use [] square brackets to get array member
    var myVar2 = myArray1[ random_num ];
    var myVar3 = myArray2[ random_num ];

       // Store new Array in local variable.
    var outputArray = new Array(myVar2, myVar3);

       // Store joined result in a variable
    var result = outputArray.join();

       // Alert the result
    alert( result );
}

findArrayparts(myArray1, myArray2);

You had it in the commented out line. Just return the value:

function getNumberRand(aNum)
{
    return Math.floor(Math.random() * aNum); 
}

You had getNumberRand right before you commented it out. You want to return the random number:

function getNumberRand(aNum)
{
 return Math.floor(Math.random() * aNum); 

}

Then when you come to want to use the return from that function later on you just assign the result to a variable:

function findArrayparts(myArray1, myArray2)    
{   
// calls getNumberRand function         
  var myVar1 = getNumberRand(myArray1.length); 

  // works out characters at same index in both arrays
  myVar2 = (myArray1(myVar1));
  myVar3 = (myArray2(myVar1)); 

  ...
}

Why are you using the global variables myVar1, myVar2, myVar3? Use return to get values out of a function.

Is this what you're trying to achieve:

<script type="text/javascript">

var myArray1 = ['red', 'orange', 'green', 'blue', 'yellow'];
var myArray2 = ['tomato', 'orange', 'apples', 'blueberry', 'banana'];

function getNumberRand(aNum)
{
    return Math.floor(Math.random() * aNum); 
}

function findArrayparts(myArray1, myArray2)    
{   
    var index = getNumberRand(myArray1.length); 
    alert(outputArraymyArray1[index] + ', ' + myArray2[index]);
}    

findArrayparts(myArray1, myArray2);


</script>