I'm working in an HTML file. I have a list of dictionaries that I got trough Flask from my Python document. I'm trying to loop over each element of the list in JavaScript and getting a the value. What I tried these solutions but they didn't work:
```for (let i = 0; i < 6; i++)
{
var value = '{{data[i]["key"]}}'
//do some stuff with it.
}```
Error:
File "/home/ubuntu/final_project/templates/results2.html", line 144,
in top-level template code var stuff = {{data[i]['key']}} File
"/usr/local/lib/python3.9/site-packages/jinja2/environment.py", line
452, in getitem return obj[argument] jinja2.exceptions.UndefinedError:
list object has no element Undefined
And without the quotes around the double braces:
```for (let i = 0; i < 6; i++)
{
var value = {{data[i]["key"]}}
//do some stuff with it.
}```
Same error.
Finally:
```for (let i = 0; i < 6; i++)
{
var temp = '{{data}}'
var value = temp[i]["key"]
//do some stuff with it.
}```
But that didnt work either. It started looping over the data character by character. (The output was 'undefined' 6 times.
However that didn't seem to work. Is there a way to get the 'i'th list of the 'data' list in JavaScript, or do I have to go back to my python file and send each dictionary trough flask one by one?
Following along with your code example, it seems that you are attempting to read the contents of your list, manipulate each item and store the new value. In ECMA6 we have the map method for these kind of operations. The map method takes a function, that's to be performed on each element of the list, then returns a new list. You will not have to declare i or loop over the list like you are doing in the old school way. Of course, there is a solution for that approach as well, but this is the modern way.
const data = [l1,l2,l3]
const newData = data.map( () => { return do_stome_stuff() }); //do some stuff
If you need to do something based on a key, you'll have to setup logic for this inside the function.
Related
I'm trying to clear all local storage when the user either completes the game loop or starts a new game, but also keep some values.
I can do this already with my sound values for volume:
// inside a conditional statement that fires when the user chooses to start a new game.
if (newGameBool === '1') {
var tst = myAu;
//myAu is the stored value that the user sets as sound using a range type input
localStorage.clear();
localStorage.setItem("Au", tst);//A newly cleared localStorage just got a new value, and it's the same as it was before.
UI.myLoad();//reload the function that uses LS to do things.
}
How do I do this for key's that have an iterating number attached to them?
Here is how I save them:
var i = +v + +1;
localStorage.setItem("v", i);
var vv = localStorage.getItem("v");
localStorage.setItem("LdrBrd_" + vv, JSON.stringify(LdrBrd));//saves all data with the iterating key name.
Calling them the way i did the sound function:
var gv = v + 1;//v calls the value from LS and adjusted for off-by-one error. gv is a local variable.
if (newGameBool === '1') {
var ldd, vg;
for (var ii = 0; ii < gv; ii++) {
var ld = localStorage.getItem("LdrBrd_" + ii);
if (ld != null) {
//these are the values that i want to pass beyond the clear point
ldd = JSON.parse(ld);//JSON string of data saved
vg = ii;//how many of them.
}
}
localStorage.clear();
for (var xx = 0; xx < vg; xx++) {
var nld = localStorage.getItem("LdrBrd_" + xx);
if (nld != null) {
localStorage.setItem("LdrBrd_" + ii, JSON.stringify(ldd));
}
}
localStorage.setItem("v", vg);
UI.myLoad();
}
I have been using console.log() in various spots to see what is going on. I comment-out the clear function just to see if the values were wrong and they don't save all all. I tried to make a fiddle, but the local storage wasn't working at all there. In visual studio, it works fine but the script to this file is almost 2000 lines long, so i tried to dress it up the best i knew how.
Thanks in advance for any help or guidance.
I was stuck on this for a few days, but i think i found something that will work, so i'll answer my own question in case there is value in posterity.
locatStorage.clear();
/* ^LS clear() function is above all new setItem codes, some variables are declared globally and some are declared at the top of the functional scope or as param^ */
var itemClass = document.querySelectorAll(".itemClass");//the strings are here
if (itemClass) {//make sure some exist
for (var p = 0; p < itemClass.length; p++) {//count them
mdd = JSON.parse(itemClass[p].innerText);//parse the data for saving
localStorage.setItem("v", v);//this is the LS item that saves the amount of items i have, it's declared at the top of the functions timeline.
localStorage.setItem("LdrBrd_" + p, JSON.stringify(mdd));//this setItem function will repeat and increment with 'p' and assign the right string back to the key name it had before.
}
}
The key is to keep the strings physically attached to an element, then call the class name. The i ran a loop counting them. 'mdd' will spit back each item i want. So then all that is left to do is re-set the item back to it's original status.
This has allowed me to create a way for my users to collect trophies and keep them even after clearing the localStorage when the he/she decides to start a new game.
I use CSS to hide the text from the string.
color:transparent;
In my gameLoop, i have a function that will read the saved strings and show them as cards just below the hidden strings.
Since you want to keep some values I recommend one of two things:
Don't call localStorage.clear() and instead only wipe out the values that you want using localStorage.removeItem('itemName'). Since you said the item names have a numeric component, maybe you can do this in a loop to reduce code.
Pull item(s) that you want saved first and restore them after calling clear(). This option is best if there are way more items that you want removed rather than saved (see below)
function mostlyClear() {
var saveMe = {};
saveMe['value1'] = localStorage.getItem('value1');
saveMe['anotherValue'] = localStorage.getItem('anotherValue');
localStorage.clear();
for(var prop in saveMe) {
if(!saveMe.hasOwnProperty(prop)) continue;
localStorage.setItem(prop, saveMe[prop]);
}
}
I'm making a plug-in where I can shorten the title of each entry in a forum index if it is too long. However, that is much harder than I expected.
Everything goes fine except when I get to the part where you actually have to print the items onto the DOM.
I get this error:
Uncaught TypeError: undefined is not a function
Here is my code with a bunch of notes I left to show you how it works.
var minimize = function() {
$('.segment').each(function(){
var title_box = $(this).children('.title');
// Selects the container of the title.
var title = $(this).children('.title').text().trim();
// Takes the child title of the each .segment class and selects its innards.
console.log(title);
var res = title.split("");
// Splits the text into an array.
console.log(res);
var fragment = [];
// initializing the empty array
for (x = 0; x < 4; x++) {
fragment.push(res[x]);
console.log(fragment);
// Loops through to make sure it's not more than 5 characters long
};
var final = fragment.join("");
// Joins the broken up string together.
title_box.empty();
final.appendTo(title_box);
});
};
What do you think I did wrong? And if there's any other ways for me to make this code more efficient, then please don't hesitate to tell me.
Right here you define fragment as an array:
var fragment = [];
You then populate it and do this:
var final = fragment.join("");
Read the docs on array.join to understand what that function does. In short, it joins your array together into a string
So now when you do this:
final.appendTo(title_box);
You get your TypeError because string doesn't have an appendTo method
What you probably wanted was a jquery object to call appendTo on.
Perhaps you meant:
title_box.text(final);
I have a program that we use at my work, which outputs its data in to XML files (several of them). I am trying to develop an HTA (yes an HTA, i'm sorry) to read these files and process their data. Unfortunately there are a number of XML files and I only need to read a few specific ones, so I am trying to write a generic "XML to array" function.
I got it to read the XML file and now I want to process the file into a 2d Array. However, since I am using a recursive function I seem to lose data. Here is the function:
NodesToArray = function (xmlDOC){
//Must redeclare "i" with each recursion, or it won't work correctly. ie: for(VAR i = 0...
for(var i = 0; i < xmlDOC.length ; i++){
//Just because it has a child still do the check.
if(xmlDOC[i].childNodes.length > 1){
//Recursively run the function.
var ReturnArray = NodesToArray(xmlDOC[i].childNodes);
//alert(ReturnArray + " " );
if(ReturnArray) return ReturnArray;
}else{
//Check to see if the node has a child node, if not and a child node is called, it will error out and stop
if(xmlDOC[i].hasChildNodes() == true){
return xmlDOC[i].firstChild.nodeValue;
}
}
}
}
Where I return the first child value I put an alert and was able to see all the data I wanted. Of course when I set it up I found it wasn't keeping the data. I've done a ton of reading and have been pounding my head against my desk and still can't come up with anything.
I've googled, searched this site, and consulted many forums, and can't find anything that would work for me. I post here reluctantly as I am at a dead end. Thanks for any help and I will provide any additional information as I can.
Just a note, but I would like to be able to do this without any libraries (specifically jQuery). The HTA doesn't seem to support a lot of newer Javascript. I'm not a professional coder by any means and learn by doing everything from scratch.
Not sure how to set the solution, but I found it
function NodesToArray(xmlDOC, returnArray){
for(var i = 0; i < xmlDOC.length ; i++){
if(xmlDOC[i].childNodes.length > 1){
returnArray[returnArray.length] = NodesToArray(xmlDOC[i].childNodes, []);
}else{
if(xmlDOC[i].hasChildNodes() == true){
returnArray[returnArray.length] = (xmlDOC[i].firstChild.nodeValue);
}
}
}
return returnArray;
}
getArray = NodesToArray(getXML.getElementsByTagName(tagName)[0].childNodes,[]);
Thanks for the help!
The general way of retrieving data recursively in the same container is to write two function:
First one is the one that you call and which returns the array
Second one is called by first function and does the recursion. To be able to put the data in the same array that function has to take it as parameter.
Here is some pseudo code
getData(node) {
_2D_array = new array[][];
getData(node, _2D_array, 0);
return array;
}
getData(node, _2D_array, depth) {
if(node) { // end of recursion ?
_2D_array[depth].add(...); // populate from node
getData(node.next, _2D_array, depth++);
}
}
Your program exits when the first element is processed because the function returns. A function can only return once. You need to move the return statements outside the loop so that the loop completes.
I have tree of javascript objects. Let's call it "family. It can contain any number of certain objects ("parents") which can each contain any number of "child" objects. The number of levels in this structure is known and each level of the tree only contains objects of one certain type.
All the objects have data and methods.
I want to save the structured data in the databese. JSON.stringify() does it perfect extracting the data and also saving the structure. But how to get back to objects? JSON.parse() fails, because it recreates the object without methods.
What should I do in this case? Should I write my own function for recreating the object from string? Or should I save the data together with methods somehow (seems a waste).
As I know the structure, it would be very handy if there would be a possibility to point to an object and tell "that's a parent object" and it would get the methods. I could easily cycle through it then. But I don't know how to that and I'm also afraid that my constructors could set some values to the default ones.
The objects constructors would look something like this:
function lines()
{
this.lines = [];
this.height = 0.5*theMargin;
this.addLine = addLine;
function addLine(newline)
{
this.lines.push(newline);
this.height += newline.height;
}
}
function aLine()
{
this.dots = [];
this.height = 0;
this.length = indent;
this.insertDot = insertDot;
function insertDot(pos,newDot)
{
this.dots.splice(pos,0,newDot);
this.length += newDot.length;
this.height = Math.max(this.height,newDot.height);
if (this.length > maxLineLength)
{ "I will not go into details here" }
}
}
Then I would do like:
var a = new lines();
var testline = new aLine();
var testdot = new aDot();
testdot.height = 10;
testdot.length = 15;
testline.insertDot(0,testdot);
a.addLine(testline);
a.addLine(testline);
Then I want to save the data about lengths and heights. And the structure, to know which dot belongs in which line.
I send that data to the webserver. I think these are the key lines to understand the used approach:
post = "name=" + name + "&tab=" + JSON.stringify(file);
req.open("POST", "saveFile.php", true);
req.send(post);
The saved file saves exactly what I wanted - the structure and data. But I don't know how to make it become an object again. I am not insisting to use JSON.stringify() method. I would enjoy any approach that would let me save the content without repeatedly saving the methods.
If you are really hooked on the idea of saving the entire object for some reason then I suggest you use the toString() method of which will essentially return the code body of a function in the form of a string when called on a function.
var obj = { func: function() { alert('hello!'); };
for(var key in obj)
if (typeof obj[key] === 'function')
alert(obj[key].toString());
You would just have to add code to serialize and store this information in addition to the json data.
All that said, you really should be simply storing the state of your objects and reloading them into your application.
EDIT: Reconstructing the object client-side
Disclaimer: I am not a PHP guy so you will be left to finding an actually coding example but I'm confident there is one out there with the power of the almighty Google.
You simply need to use your serializing/deserializing class to serialize the data back into your object.
So imagine the section of pseudo code is the php file for the particular page in question:
<?php
<html>
<head>
<script type="text/javascript">
var model = /* Use serializing class on your server-side object */;
//Now you just need to build a function into your objects that is much like a constructor that can receive this model and rebuild the object
function rebuildObject(yourObject, jsonModel) {
//assign first property
//assign second etc...
}
</script>
</head>
<body>
</body>
</html>
?>
You are essentially templating the json data back to the page in a script tag so you can access it client-side. The javascript interpretter will automatically convert the json into an actual js object that your code can use so no issue there.
In the end I chose the straightforward way to recreate all the objects and copy the data. It turned out to be shorter and nicer than I had imagined before. In case it is useful for anyone else, here's how I did it:
data = JSON.parse(file);
a = new lines();
a.height = data.height;
for (var i=0; i<data.lines.length; i++)
{
a.lines.push(new aLine());
a.lines[i].height = data.lines[i].height;
a.lines[i].length = data.lines[i].length;
for (var j=0; j<data.lines[i].dots.length; j++)
{
a.lines[i].dots.push(new aDot());
[... and so on ...]
}
}
I know there are a lot of questions about this, but I can't find the solution to my problem and have been on it for a while now. I have two sets of input fields with the same name, one for product codes, and one for product names. These input fields can be taken away and added to the DOM by the user so there can be multiple:
Here is what I have so far, although this saves it so there all the codes are in one array, and all the names in another:
var updatedContent = [];
var varCode = {};
var varName = {};
$('.productVariationWrap.edit input[name="varVariationCode[]"]')
.each(function(i, vali){
varCode[i] = $(this).val();
});
$('.productVariationWrap.edit input[name="varVariationName[]"]')
.each(function(i1, vali1){
varName[i1] = $(this).val();
});
updatedContent.push(varCode);
updatedContent.push(varName);
I am trying to get it so the name and code go into the same array. i.e. the code is the key of the K = V pair?
Basically so I can loop through a final array and have the code and associated name easily accessible.
I can do this in PHP quite easily but no luck in javascript.
EDIT
I want the array to look like:
[
[code1, name1],
[code2, name2],
[code3, name3]
];
So after I can do a loop and for each of the arrays inside the master array, I can do something with the key (code1 for example) and the associated value (name1 for example). Does this make sense? Its kind of like a multi-dimensional array, although some people may argue against the validity of that statement when it comes to Javascript.
I think it's better for you to create an object that way you can access the key/value pairs later without having to loop if you don't want to:
var $codes = $('.productVariationWrap.edit input[name="varVariationCode[]"]'),
$names = $('.productVariationWrap.edit input[name="varVariationName[]"]'),
updatedContent = {};
for (var i = 0, il = $codes.length; i < il; i++) {
updatedContent[$codes.get(i).value] = $names.get(i).value;
}
Now for example, updatedContent.code1 == name1, and you can loop through the object if you want:
for (var k in updatedContent) {
// k == code
// updatedContent[k] == name
}
Using two loops is probably not optimal. It would be better to use a single loop that collected all the items, whether code or name, and then assembled them together.
Another issue: your selectors look a little funny to me. You said that there can be multiple of these controls in the page, but it is not correct for controls to have duplicate names unless they are mutually exclusive radio buttons/checkboxes--unless each pair of inputs is inside its own ancestor <form>? More detail on this would help me provide a better answer.
And a note: in your code you instantiated the varCode and varName variables as objects {}, but then use them like arrays []. Is that what you intended? When I first answered you, i was distracted by the "final output should look like this array" and missed that you wanted key = value pairs in an object. If you really meant what you said about the final result being nested arrays, then, the smallest modification you could make to your code to make it work as is would look like this:
var updatedContent = [];
$('.productVariationWrap.edit input[name="varVariationCode[]"]')
.each(function(i, vali){
updatedContent[i] = [$(this).val()]; //make it an array
});
$('.productVariationWrap.edit input[name="varVariationName[]"]')
.each(function(i1, vali1){
updatedContent[i1].push($(this).val()); //push 2nd value into the array
});
But since you wanted your Code to be unique indexes into the Name values, then we need to use an object instead of an array, with the Code the key the the Name the value:
var updatedContent = {},
w = $('.productVariationWrap.edit'),
codes = w.find('input[name="varVariationCode[]"]'),
names = w.find('input[name="varVariationName[]"]');
for (var i = codes.length - 1; i >= 0; i -= 1) {
updatedContent[codes.get(i).val()] = names.get(i).val();
});
And please note that this will produce an object, and the notation will look like this:
{
'code1': 'name1',
'code2': 'name2',
'code3': 'name3'
};
Now you can use the updatedContent object like so:
var code;
for (code in updatedContent) {
console.log(code, updatedContent[code]); //each code and name pair
}
Last of all, it seems a little brittle to rely on the Code and Name inputs to be returned in the separate jQuery objects in the same order. Some way to be sure you are correlating the right Code with the right Name seems important to me--even if the way you're doing it now works correctly, who's to say a future revision to the page layout wouldn't break something? I simply prefer explicit correlation instead of relying on page element order, but you may not feel the need for such surety.
I don't like the way to solve it with two loops
var updatedContent = []
$('.productVariationWrap.edit').each(function(i, vali){
var $this = $(this)
, tuple = [$this.find('input[name="varVariationCode[]"]').val()
, $this.find('input[name="varVariationName[]"]').val()]
updatedContent.push(tuple)
});