I have an array of strings, you can see below and i want to alert each element one by one on button click:
function mysimplefunc() {
var i = 0;
var array = ["a", "b", "c", "d"];
if (array.length < 4)
{
var str = array[i];
i++;
alert(str);
}
}
below is asp code:
<asp:Button ID="btn_SHow" runat="server" Text="Show Elements" OnClientClick="mysimplefunc();" />
But its not working.
the if loop will not working since array length is 4
and u must use for loop inorder to iterate each element..!!
for ( i=0;i<array.length;i++)
{
var str = array[i];
alert(str);
}
Try this function. This handles creating the array counter (i) as a global variable, and any number of items can be included in the array, not just four.
function mysimplefunc() {
var array = ["a", "b", "c", "d"];
if (typeof i == "undefined") {i = 0};
alert(array[i++]);
if (i == array.length) {i = 0}
}
function mysimplefunc() {
var i = 0; //declare & initialise a integer variable used for loop counter.
var array = ["a", "b", "c", "d"]; //Create an string array of 4 elements with name array
var arrLength=array.length; //find the length of array elements
for (;i<arrLength;) //iterate over the array elements upto last element
{
var str = array[i]; //take first element from array
i++; //increment the loop counter
alert(str);//popup the small window with values present in array
}
}
Related
I am trying to remove only items that were pushed into a list so that I am only left with the original list items
const list = ["a", "b", "c", "d"];
for (let i = 0; i < 4; i++) {
list.push(i);
}
console.log(list);
// outputs: a,b,c,d,1,2,3,4 // as expected
// how can we remove only the pushed items.
list.pop;
console.log(list);
// outputs : []
// desired output: a,b,c,d
I'm not sure what your case is and why you want to extract the items from the array but anyway.
The first option would be: duplicating the array into another variable
or the second option: extracting it using splice when you know the length of the original array.
Snippets:
const list = ["a", "b", "c", "d"];
const original = list.slice(); // duplicating array
const originalLength = list.length // getting original length
for (let i = 0; i < 4; i++) {
list.push(i);
}
console.log("original1: ", original);
console.log("original2: ", list.slice(0, originalLength));
You can remove the elements from the index where you have begun pushing new elements using splice.
const list = ["a", "b", "c", "d"];
for (let i = 0; i < 4; i++) {
list.push(i);
}
list.splice(list.length - 4)
console.log(list);
If you need two to have one "for loop" pushing items into an array, and then remove those same items in another loop, then a simple solution would be
Snippet:
const list = ["a", "b", "c", "d"];
for (let i = 0; i < 4; i++) {
list.push(i);
}
for (let j of list) {
if (j) {
list.pop();
}
};
console.log(list);
Example
If my values are in array like this
var myPlaces = ["a", "b", "c"];
var friendPlaces = ["d", "0", "e"];
for(var i = 0; i < myPlaces.length; i++) {
console.log(myPlaces[i]);
for(var j = 0; j < friendPlaces.length; j++) {
if (myPlaces[i] == friendPlaces[i]) {
console.log(myPlaces[i]);
};
I need answer as
(a,d)(b,0)(c,e) as three result but it gives count more than 3
help me to modify my current answer (a,d) (d,a) (d,b) (d,c) then (b,o)
You can use Array#map (Assuming your input arrays are of same length with fixed count of arrays- i.e. 2 in your case).
If you use map on myPlaces then 1st parameter is current value of myPlaces in loop and the 2nd parameter is index of that element in array. So you can match current element in myPlaces with elements from friendPlaces array with the same index using this index.
var myPlaces = ["a", "b", "c"];
var friendPlaces = ["d", "0", "e"];
var result = myPlaces.map((e, i) => "("+e +","+ friendPlaces[i]+")");
console.log(result);
I have 2 array and want to remove the elements of 2nd array as per position numbers on 1st array.
var notexists = []; //value is "1","5","8" on 0,1,2nd position.
var copyrequiredfields = [];//Value is "a","b","c","d","e","f",...
for (var i = 0; i < notexists.length; i++) {
copyrequiredfields.splice(parseInt(notexists[i]), 1);
}
as per example i want to remove 1st 5th and 8th element from copyrequiredfields .
Please suggest some answer.
Create a new array, iterate the copyrequiredfields, when the index in notexists, ignore it.
example:
var notexist = [1,2,5];
var copyrequiredfields = ['a','b','c','d','e','f','g'];
//create a index map
var index_map = {};
for(var i = 0; i < notexist.length; i++){
index_map[notexist[i]] = true;
}
//remove the elements
var newarray = [];
for(var i = 0; i < copyrequiredfields.length; i++){
if(!index_map[i]){
newarray.push(copyrequiredfields[i]);
}
}
copyrequiredfields = newarray;
In JS, index of array starts with 0 and not 1 so you just have to subtract 1 from value before splice. Rest of the code is fine.
One issue is, as you remove elements from array, elements after it are moved 1 position back. This will give you incorrect output. 1 hack is to count number of elements removed to count movement.
A better solution would be to use array.filter.
Array.splice
var notexists = ["1", "5", "8"]; //value is on 0,1,2nd position.
var copyrequiredfields = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]; //Value is "a","b","c","d","e","f",...
var count=0;
for (var i = 0; i < notexists.length; i++) {
console.log(+notexists[i] - 1)
copyrequiredfields.splice(+notexists[i]-1-count++, 1);
}
console.log(copyrequiredfields)
Array.filter
var notexists = ["1", "5", "8"]; //value is on 0,1,2nd position.
var copyrequiredfields = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]; //Value is "a","b","c","d","e","f",...
var r = copyrequiredfields.filter((x,i)=>notexists.indexOf((i+1).toString()) === -1)
console.log(r)
You could copy the whole array, except of the parts you dont need anymore:
var tempCopy = [];
for (var i=0; i < copyrequiredfields.length; i++)
if(notexists.indexOf(i)==-1)
tempCopy.push(copyrequiredfields[i]);
copyrequiredfields = tempCopy;
Greets!
I am trying to add index of an array element when converting an Array into a string. Here is my code
var arr = ["a", "b", "c", "d", "e"];
console.log(arr.join('')); // Will log "abcdef"
But my required output is a0b1c2d3e4.
If I write like below, I will get the result
var str = "";
for(var i = 0, l = arr.length; i++){
str += (arr[i] + i);
}
console.log(str);
But I would like to know if any trick is there with Array.join()
You can use Array.prototype.map for it, see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
arr.map(function(val, index) { return val + index.toString(); }).join("");
I have an array that after being sorted appears like this:
var arr = ["a", "a", "b", "b", "b", "b", "c", "c", "c"];
There are 2 "a" Strings, 4 "b" Strings, and 3 "c" Strings.
I am trying to return 3 separate arrays, returning them one at a time from a loop, containing only matching values. So, upon the first iteration, the returned array would appear as newArr = ["a", "a"], the second as newArr = ["b", "b", "b", "b"] and on the third iteration as newArr = ["c", "c", "c"].
However, this is a small array of predefined values, and I need an algorithm that can perform the same operation on an array of unknown size, unknown elements, and with an unknown number of like elements. (and keep in mind that the array is already sorted to begin with, in this context)
Here's my crazy code that is displaying some unusual, and incorrect, results:
var arr = ["a", "a", "b", "b", "b", "b", "c", "c", "c"];
for(var index = 0; index < arr.length; index++)
{
var test = "";
var newArr = []; // resets the new array upon each iteration
var str = arr[index]; // initialized as the next unique index-value
for(var i = index; i < arr.length; i++)
{
if(arr[i] == str)
{
newArr.push(arr[k]);
test += arr[i] + " ";
}
else
{
index = i; // changing the outer loop variable
break; // exiting the inner loop
}
} // end of inner loop
window.alert(test);
setValues(newArr);
} // end of outer loop
function setValues(arrSorted)
{
var here = document.getElementById("here");
for(var i = 0; i < arrSorted.length; i++)
{
here.innerHTML += arrSorted[i] + " ";
}
here.innerHTML += "<br />";
} // end of setValues function
var arr = ["a", "a", "b", "b", "b", "b", "c", "c", "c"];
var arrays = {};
for (var i=0;i<arr.length;i++) {
if (!arrays[arr[i]]) arrays[arr[i]] = [];
arrays[arr[i]].push(arr[i]);
}
this will give you the equivalent of
arrays = {};
arrays['a'] = ['a','a'];
arrays['b'] = ['b','b','b','b','b'];
arrays['c'] = ['c','c','c'];
You can use a function like this to divide the array into several arrays:
function divide(arr) {
var subArrays = [];
var current = null;
var subArray = null;
for (var i = 0; i < arr.length; i++) {
if (arr[i] != current) {
if (subArray != null) subArrays.push(subArray);
current = arr[i];
subArray = [];
}
subArray.push(arr[i]);
}
if (subArray != null) subArrays.push(subArray);
return subArrays;
}
Demo: http://jsfiddle.net/Guffa/d8CBD/
This is how I would do it:
var arr = ["a", "a", "b", "b", "b", "b", "c", "c", "c"];
var out = [], prev;
for (var i = 0, j = 0, len = arr.length; i < len; i++) {
if (arr[i] !== prev || !out.length) {
out[j++] = [prev = arr[i]];
} else {
out[j - 1].push(prev);
}
}
//out -> [["a","a"],["b","b","b"],["c","c","c"]]
Demo
Note: the || !out.length check is just handle arrays that start with undefined correctly, but feel free to remove it if this will never be the case