Reindexing an array
Here is my example.
Can you tell me how can I make 开发者_运维技巧the array have consecutive keys? I want to reindex my array.
Currently I have:
var testArray = new Array();
testArray[3]="qwerty";
testArray[7]="asdfgh";
testArray[13]="zxcvbn";
console.log(testArray);
But I'd like to get the values at indices 0, 1 and 2 (and so on):
["qwerty", "asdfgh", "zxcvbn"]
Array.prototype.filter()
is not executed on deleted or previously undefined items. So you can simply do:
testArray.filter(function(val){return val});
..in order to re-index your array.
Or ES6:
testArray.filter(val => val)
If you don't mind using javascript 1.6: (note: this code uses the jQUery library)
var testArray = new Array();
testArray[3]="qwerty";
testArray[7]="asdfgh";
testArray[13]="zxcvbn";
var testString = testArray.filter(function (item) { return item != undefined }).join();
$(function(){
$('#write').text(testString);
});
filter prototype:
if (!Array.prototype.filter)
{
Array.prototype.filter = function(fun /*, thisp */)
{
"use strict";
if (this === void 0 || this === null)
throw new TypeError();
var t = Object(this);
var len = t.length >>> 0;
if (typeof fun !== "function")
throw new TypeError();
var res = [];
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in t)
{
var val = t[i]; // in case fun mutates this
if (fun.call(thisp, val, i, t))
res.push(val);
}
}
return res;
};
}
You could filter the array by using a callback which returns true
or other truthy value, because Array#filter
omits sparse elements.
If Boolean
is taken, the result filters not only sparse items, but items which have a falsy value. To prevent this, take a callback which returns true
for every element.
array.filter(_ => true);
var array = [];
array[10] = 0;
array[20] = 0;
array[30] = 0;
console.log(array.filter(_ => true).join('|'))
Super simple function:
function reindex_array_keys(array, start){
var temp = [];
start = typeof start == 'undefined' ? 0 : start;
start = typeof start != 'number' ? 0 : start;
for(var i in array){
temp[start++] = array[i];
}
return temp;
}
testArray = reindex_array_keys(testArray);
Note: this will blow away any custom keys. the result will always be numerically indexed. you could add in checks for if it's an array or not but i tend to just not use functions i build other than they are intended to be used. you can also start the index higher if you like:
testArray = reindex_array_keys(testArray, 3);
which will produce 3 'undefined' items at the beginning of the array. you can then add to it later but i think it would be better to do testArray.unshift('newValue')
first then reindex personally.
have fun
var testArray = new Array();
testArray[3] = "qwerty";
testArray[7] = "asdfgh";
testArray[13] = "zxcvbn";
var isEmpty = function(x) {
// returns true if x is null and false if it is not.
if(x!=null){
return true;
}else{
return false
}
}
var newArray=testArray.filter(isEmpty);
var testString2 = newArray.join();
$('#write').text(testString2);
To reindex an array, use Object.values
:
var sparseArray = new Array();
sparseArray[3] = "qwerty";
sparseArray[7] = "asdfgh";
sparseArray[13] = "zxcvbn";
let result = Object.values(sparseArray);
console.log(result);
testArray = testArray.filter(Boolean)
This should re-index your array.
Maybe this is simpler to solve the problem:
var j=0;
var tmpTab=[];
for(var i in origTab) {
tmpTab[j]=origTab[i];
++j;
}
origTab=tmpTab;
delete tmpTab;
you mean without the commas? if so just do this var testString = testArray.join("");
or you can add any char you want between.
Try This
var testArray=testArray.join(" ");
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