I have an array in javascript like this (1,2,3,4,5,6,7,8) and i want to remove al the values that are smaller than 5. So the array that remains is (1,2,3,4). How to do this with javascript or jquery...
You can filter the array with array.filter()
var array = [1,2,3,4,5,6,7,8];
var new_array = array.filter(function(item) {
return item < 5;
});
FIDDLE
or if you have to support IE8 and below, you can do it the old fashion way
var array = [1,2,3,4,5,6,7,8],
new_array = [];
for (var i=0; i<array.length; i++) {
if (array[i] < 5) new_array.push(array[i])
}
FIDDLE
I think you want to remove items larger than 5, but jquery grep should do it:
https://api.jquery.com/jQuery.grep/
Use .map(). This will remove values less than 5 and remaining array values will be removed from array.
var arr = $.map( [ 1,2,3,4,5,6,7,8 ], function( n ) {
return n < 5 ? n : null;
});
console.log(arr);
DEMO
or
Use .grep(). This will remove values less than 5 and remaining values will be removed from the array.
var arr = $.grep( [ 1,2,3,4,5,6,7,8 ], function( n ) {
return n < 5;
});
console.log(arr);
DEMO
I will suggest you to go with grep based on jsperf result.
http://jsperf.com/map-vs-grep/2
var orig= [1,2,3,4,5,6,7,8];
just in case they're out of order:
var copy=orig.sort();
then:
var result = copy.splice(0,copy.lastIndexOf(4)+1);
http://jsfiddle.net/LXaqe/
In this case you can use JavaScript is good in compare of jQuery. Because JavaScript *Execution* fast compare to a jQuery.
Check this Demo jsFiddle
JavaScript
var filtered = [1,2,3,4,5,6,7,8].filter(issmall);
function issmall(element) {
return element < 5 ;
}
console.log(filtered);
Result
[1, 2, 3, 4]
JavaScript filter() Method
Var arr = [1,2,3,4,5,6,7];
var newarr = [];
For(var i=0 ; i<=arr.length ; i++){
if(arr[i] < 5){
newarr.push(arr[i]);
}
}
Related
I'm trying to access elements from a JavaScript array:
[["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]]
I want to access
1, 2, 3, 4, 5, 6 separately in a variable and John, Rajan, Hitesh, Vin, Ritwik, Sherry separately in a variable.
I tried converting it to a string and split(), but it doesn't work.
this is code i tried
var jArray = <?php echo json_encode($newarray); ?> ;
var nJarr = jArray[0]; nJarr.toString();
var res = nJarr.split(","); var apname = res[0];
alert(apname);
but there's no alert appearing on the screen
If you are open to using Underscore, then it's just
var transposed = _.zip.apply(0, arr);
and the arrays you are looking for will be in transposed[0] and transposed[1].
You can write your own transpose function fairly easily, and it's more compact if you can use ES6 syntax:
transpose = arr => Object.keys(arr[0]).map(i => arr.map(e => e[i]));
>> transpose([["1","John"], ["2","Rajan"], ...]]
<< [[1, 2, ...], ["John", "Rajan", ...]]
If you want an ES5 version, here's one with comments:
function transpose(arr) { // to transpose an array of arrays
return Object.keys(arr[0]) . // get the keys of first sub-array
map(function(i) { // and for each of these keys
arr . // go through the array
map(function(e) { // and from each sub-array
return e[i]; // grab the element with that key
})
))
;
}
If you prefer old-style JS:
function transpose(arr) {
// create and initialize result
var result = [];
for (var i = 0; i < arr[0].length; i++ ) { result[i] = []; }
// loop over subarrays
for (i = 0; i < arr.length; i++) {
var subarray = arr[i];
// loop over elements of subarray and put in result
for (var j = 0; j < subarray.length; j++) {
result[j].push(subarray[j]);
}
}
return result;
}
Do it like bellow
var arr = [["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]];
var numbers = arr.map(function(a){return a[0]}); //numbers contain 1,2,3,4,5
var names = arr.map(function(a){return a[1]}); //names contain John,Rajan...
Try this:
var data = [["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]];
var IDs = [];
var names = [];
for(i=0; i<data.length; i++)
{
IDs.push(data[i][0]);
names.push(data[i][1]);
}
console.log(IDs);
console.log(names);
Here is the working fiddle.
Hi i have the below array element
var array =["a.READ","b.CREATE"]
I'm trying to split the elements based on "." using javascript split method
below is my code
var array1=new Array();
var array2 = new Array();
for (var i = 0; i < array .length; i++) {
array1.push(array [i].split("."));
}
console.log("this is the array1 finish ----"+array1)
The out put that i'm receiving is
[["a","READ"],["b","CREATE"]]
The expected output that i want is
array1 =["a","b"]
array2=["READ","CREATE"]
I'm stuck here any solution regarding this is much helpful
You need to add to array2 and use both elements from the returned array that String.prototype.split returns - i.e. 0 is the left hand side and 1 is the right hand side of the dot.
var array = ["a.READ", "b.CREATE"]
var array1 = []; // better to define using [] instead of new Array();
var array2 = [];
for (var i = 0; i < array.length; i++) {
var split = array[i].split("."); // just split once
array1.push(split[0]); // before the dot
array2.push(split[1]); // after the dot
}
console.log("array1", array1);
console.log("array2", array2);
We'll start off with a generic transpose function for two-dimensional arrays:
function transpose(arr1) { // to transpose a 2d array
return arr1[0].map( // take the first sub-array and map
function(_, i) { // each element into
return arr1.map( // an array which maps
function(col) { // each subarray into
return col[i]; // the corresponding elt value
}
);
}
);
}
Now the solution is just
transpose( // transpose the two-dimensional array
array.map( // created by taking the array and mapping
function(e) { // each element "a.READ" into
return e.split('.'); // an array created by splitting it on '.'
}
)
)
You are adding nothing to array2. Please use indexes properly , like below:
var array1=new Array();
var array2 = new Array();
for (var i = 0; i < array .length; i++) {
array1.push(array [i].split(".")[0]);
array2.push(array [i].split(".")[1]);
}
you can do something like this
var array =["a.READ","b.CREATE"];
var arr1= [], arr2= [];
array.forEach(function(item,index,arr){
item.split('.').forEach(function(item,index,arr){
if(index % 2 === 0){
arr1.push(item);
}else{
arr2.push(item);
}
});
});
console.log(arr1);
console.log(arr2);
DEMO
I guess this is a bit redundant but, the split method actually returns and array. Although your code was off you were not modifying array2. Consider the following.
var array = [ "a.READ" , "b.CREATE" ]
, array1 = []
, array2 = []
// cache array length
, len = array.length;
for ( var i = 0; i < len; i++ ) {
// the split method returns a new array
// so we will cache the array
// push element 0 to array1
// push element 1 to array2
var newArr = array[ i ].split('.');
array1.push( newArr[ 0 ] );
array2.push( newArr[ 1 ] );
}
console.log( 'array1: ', array1 );
console.log( 'array2: ', array2 );
Use this:
for (var i = 0; i < array .length; i++) {
var parts = array[i].split('.');
array1.push(parts[0]);
array2.push(parts[1]);
}
You have not assigned any value to Array2. You can do as shown below.
var array1=[];
var array2 = [];
for (var i = 0; i < array .length; i++) {
var arrayTemp=[];
arrayTemp.push(array [i].split("."));
array1.push(arrayTemp[0]);
array2.push(arrayTemp[1]);
}
Ok, this might be easy for some genius out there but I'm struggling...
This is for a project I'm working on with a slider, I want an array the slider can use for snap points/increments... I'm probably going about this in a mental way but its all good practice! Please help.
var frootVals = [1,2,3,4,5];
var frootInc = [];
for (i=0; i<=frootVals.length; i++) {
if (i == 0){
frootInc.push(frootVals[i]);
}
else{
frootInc.push(frootInc[i-1] += frootVals[i])
}
};
What I'm trying to do is create the new array so that its values are totals of the array elements in frootVals.
The result I'm looking for would be this:
fruitInc = [1,3,6,10,15]
For a different take, I like the functional approach:
var frootVals = [1,2,3,4,5];
var frootInc = [];
var acc = 0;
frootVals.forEach(function(i) {
acc = acc + i;
frootInc.push(acc);
});
var frootVals = [1,2,3,4,5]
, frootInc = [];
// while i < length, <= will give us NaN for last iteration
for ( i = 0; i < frootVals.length; i++) {
if (i == 0) {
frootInc.push(frootVals[i]);
} else {
// rather than frootIne[ i-1 ] += ,
// we will just add both integers and push the value
frootInc.push( frootInc[ i-1 ] + frootVals[ i ] )
}
};
There were a few things wrong with your code check out the commenting in my code example. Hope it helps,
This will do:
var frootVals = [1,2,3,4,5];
var frootInc = [];
for (i=0; i < frootVals.length; i++) { // inferior to the length of the array to avoid iterating 6 times
if (i == 0) {
frootInc.push(frootVals[i]);
}
else {
frootInc.push(frootInc[i-1] + frootVals[i]) // we add the value, we don't reassign values
}
};
alert(JSON.stringify(frootInc));
jsfiddle here: http://jsfiddle.net/f01yceo4/
change your code to:
var frootVals = [1,2,3,4,5];
var frootInc = [frootvals[0]]; //array with first item of 'frootVals' array
for (i=1; i<frootVals.length; i++) {
frootInc.push(frootInc[i-1] + frootVals[i]); //remove '='
}
Here's a very simple pure functional approach (no vars, side-effects, or closures needed):
[1,2,3,4,5].map(function(a){return this[0]+=a;}, [0]);
// == [1, 3, 6, 10, 15]
if you name and un-sandwich the function, you can use it over and over again, unlike a hard-coded var name, property name, or for-loop...
I need to iterate from 0 to 30, but I want to do this with help of forEach:
new Array(30).forEach(console.log.bind(console);
Of course this does not work, therefor I do:
new Array(30).join(',').split(',').forEach(console.log.bind(console));
Is there other ways to fill empty arrays?
Actually, there's a simple way to create a [0..N) (i.e., not including N) range:
var range0toN = Object.keys(Array.apply(0,Array(N)));
Apparently Object.keys part can be dropped if you only want to get a proper array of N elements.
Still, like others said, in this particular case it's probably better to use for loop instead.
if you want all of item have same value, do this
var arrLength = 4
var arrVal = 0
var newArr = [...new Array(arrLength)].map(x => arrVal);
// result will be [0, 0, 0, 0]
You could try using a for loop. new Array is not a best practise
var index, // we use that in the for loop
counter, // number of elements in array
myArray; // the array you want to fill
counter = 30;
myArray = [];
for (index = 0; index < counter; index += 1) {
myArray[index] = [];
/*
// alternative:
myArray.push([]);
// one-liner
for (index = 0; index < counter; index += 1) myArray.push([]);
*/
}
If you simply want to iterate, then use for loop like this
for (var i = 0; i < 30; i += 1) {
...
...
}
Actually, if you are looking for a way to create a range of numbers, then you can do
console.log(Array.apply(null, {length: 30}).map(Number.call, Number));
It will create numbers from 0 to 29. Source : Creating range in JavaScript - strange syntax
If you insist foreach
var data = [1, 2, 3];
data.forEach(function(x) {
console.log(x);
});
I have an array with name "ids" and some values like ['0','567','956','0','34']. Now I need to remove "0" values from this array.
ids.remove ("0"); is not working.
Here's a function that will remove elements of an array with a particular value that won't fail when two consecutive elements have the same value:
function removeElementsWithValue(arr, val) {
var i = arr.length;
while (i--) {
if (arr[i] === val) {
arr.splice(i, 1);
}
}
return arr;
}
var a = [1, 0, 0, 1];
removeElementsWithValue(a, 0);
console.log(a); // [1, 1]
In most browsers (except IE <= 8), you can use the filter() method of Array objects, although be aware that this does return you a new array:
a = a.filter(function(val) {
return val !== 0;
});
Use splice method in javascript. Try this function:
function removeElement(arrayName,arrayElement)
{
for(var i=0; i<arrayName.length;i++ )
{
if(arrayName[i]==arrayElement)
arrayName.splice(i,1);
}
}
Parameters are:
arrayName:- Name of the array.
arrayElement:- Element you want to remove from array
Here's one way to do it:
const array = ['0', '567', '956', '0', '34'];
const filtered = array.filter(Number);
console.log(filtered);
For non-trivial size arrays, it's still vastly quicker to build a new array than splice or filter.
var new_arr = [],
tmp;
for(var i=0, l=old_arr.length; i<l; i++)
{
tmp = old_arr[i];
if( tmp !== '0' )
{
new_arr.push( tmp );
}
}
If you do splice, iterate backwards!
For ES6 best practice standards:
let a = ['0','567','956','0','34'];
a = a.filter(val => val !== "0");
(note that your "id's" are strings inside array, so to check regardless of type you should write "!=")
Below code can solve your problem
for(var i=0; i<ids.length;i++ )
{
if(ids[i]=='0')
ids.splice(i,1);
}
ids.filter(function(x) {return Number(x);});
I believe, the shortest method is
var newList = ['0', '567', '956', '0', '34'].filter(cV => cV != "0")
You could always do,
listWithZeros = ['0', '567', '956', '0', '34']
newList = listWithZeros.filter(cv => cv != "0")
The newList contains your required list.
Explanation
Array.prototype.filter()
This method returns a new array created by filtering out items after testing a conditional function
It takes in one function with possibly 3 parameters.
Syntax:
Array.prototype.filter((currentValue, index, array) => { ... })
The parameters explain themselves.
Read more here.
The easy approach is using splice!!. But there's a problem, every time you remove an element your array size will constantly reduce. So the loop will skip 1 index the array size reduces.
This program will only remove every first zero.
// Wrong approach
let num = [1, 0, 0, 2, 0, 0, 3,];
for(let i=0; i<num.length; i++){
if(num[i]==0)
num.splice(i, 1);
}
console.log(num)
the output will be
[1,0,2,0,3]
So to remove all the zeros you should increase the index if you found the non-zero number.
let i = 0;
while(i<num.length){
if(num[i]==0){
num.splice(i,1);
}
else{
i++;
}
}
But there's a better way. Since changing the size of the array only affects the right side of the array. You can just traverse in reverse and splice.
for(let i=num.length-1; i>=0; i--){
if(num[i]===0)
num.splice(i,1);
}