I need a function that basically just multiplies members of an array by 100. The number of members of the array may change. Also, I can't use something like array.prototype.map - it has to be a loop.
Here's what I've got so far, but newArray comes back as undefined... What am I doing wrong?
var a = [1, 2, 3];
function toPts(array){
for(var i=0; i<array.length; i++){
array[i] *= 100;
}
}
var newArray = toPts(a);
The end result needed is newArray = [100, 200, 300]
You forgot to return the array. If you just want to modify existing one, you only need to do:
toPts(a);
console.log(a) // [100,200,300]
If you want a new array with original untouched:
function toPts(array){
var arr = array.slice(0); // copy array to new reference
for(var i=0; i<arr.length; i++){
arr[i] *= 100;
}
return arr;
}
var newArray = toPts(a);
console.log(newArray) // [100,200,300]
console.log(a) // [1,2,3]
.length is a property and not something calculated when called, so its the same as storing in a variable. Only IE seems to benefit from catching array lengthfunction toPts(array){
for(var i=0; i<array.length; i++){
array[i] *= 100;
}
return array;
}
You didn't return the array to the outside.
However, note you are modifying the original array, so it doesn't make much sense to have it in two variables.
Probably, you want to copy it:
function toPts(array){
var newArray = array.slice();
for(var i=0; i<newArray.length; i++){
newArray[i] *= 100;
}
return newArray;
}
var a = [1, 2, 3],
newArray = toPts(a); // `a` is not altered
a is multiplied in-place as its passed by reference, so after the function (which returns nothing)
toPts(a);
alert(a) // 100,200,300
you are not returning anything from the function, you just need to return the modified array inside the function (after the loop has finished executing)
like
var a = [1, 2, 3];
function toPts(array){
for(var i=0; i<array.length; i++){
array[i] *= 100;
}
return array;
}
var newArray = toPts(a);
by default function return undefined when it does not return anything.your a array already changed to resulted array.
var a = [1, 2, 3];
function toPts(array){
for(var i=0; i<array.length; i++){
array[i] *= 100;
}
}
console.log(a);//this give you resulted output becuse array is passing as call by reference. so changes made in the same array
