Saturday, April 26, 2014

Apply function to array elements to create another array, map()

This example show how to create array by applying function to a existing array, using map().

<!DOCTYPE html>
<html>
<body onload="doit();">

<h1>mobile-web-app.blogspot.com</h1>
<p id="p1"></p>
<div id="resultdiv"></div>
 
<script type="text/javascript">
 
function doit()
{   var array = [0, 45, 90, 180, 270, 360];

    document.getElementById("p1").innerHTML=array;
    var resultDiv = document.getElementById("resultdiv");
    
    var array2 = array.map(function(x) {return Math.sin(x * (Math.PI / 180))});
    printAll(array2, resultDiv);
    
    var array3 = array.map(cos);
    printAll(array3, resultDiv);
    
}

function cos(x){
    return Math.cos(x * (Math.PI / 180));
}

function printAll(arr, container){
    arr.forEach(
        function(element, index){
            var newP = document.createElement("p");
            newP.innerHTML = index + " : " + element;
            container.appendChild(newP);
        }
    );
}

</script>
</body>
</html>




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