I good with php but javascript is not good with me, my english also not very good but im explaining everything as best and slowly in step by step.
I make calculation for charges for a telecom service using javascript. I know similar logic with in php has to be used but Then I stuck.
/prices is json from server as see below.
var prices = [{"brand":"Airtel (Waridtel) Ug","numbering":"25670","price":"40"},
{"brand":"UTL ug","numbering":"25671","price":"30"},
{"brand":"Airtel Ug","numbering":"25675","price":"40"},
{"brand":"MTN Ug","numbering":"25677","price":"20"},
{"brand":"MTN Ug","numbering":"25678","price":"20"},
{"brand":"Orange Ug","numbering":"25679","price":"30"},
{"brand":"Safaricom Ke","numbering":"25470","price":"30"},
{"brand":"Safaricom Ke","numbering":"25471","price":"30"}]
a user provide the various telephone Numbers in comma seperation string
//contacts
cdest = '245772306640,256754306640,25471624525,2567825689754,2563989654285,4588623566', 256782658974;
we use brand prefix to find brand.
if contacts prefix is equivalent to price numbering in json, then that is conctact which is owned by that brand. I calculate how many contact per brand and total cost basing on contact list user provide.
Expecting output is shown below.
brand(number of contacts)::total cost
Example MTN Ug(3)::60 , Airtel Ug(1), Safaricom Ke(1)::30,
Im also like to place any number with no a brand under a universal brand wich is called International with no a price assign as see below example
International(2)::default,
Here Im very confuse with two loops, im not understand how I can loop , count and echo but Im good with transfer of php knowledge so far I create double loop, but then I confuse again.
//explode numbers;
dest = cdest.split(",");
// loop through brands and numbers.
//plan is to create create array like (brand1 =>countbrand1,brand2=>countbrand3, etc)
cd = Array();
for( var i=0; i<dest.length; i++ )
{
$x.each(prices, function(index, m) {
if(dest[i].indexOf(m.numbering)==0)
{
cd[m.brand]+=1;
} else
cd[International]+=1;
});
}
In php I simply loop on cd now and get output. I try for js, but dont know how to echo the key of array in Javascript. javascript is bullying me whole day. If you make good answer, please you show in slow step by step. Im very thankful.
You can check this fiddle that I have created from your code. May help you
http://jsfiddle.net/GSeZ9/
var prices = [{"brand":"Airtel (Waridtel) Ug","numbering":"25670","price":"40"},
{"brand":"UTL ug","numbering":"25671","price":"30"},
{"brand":"Airtel Ug","numbering":"25675","price":"40"},
{"brand":"MTN Ug","numbering":"25677","price":"20"},
{"brand":"MTN Ug","numbering":"25678","price":"20"},
{"brand":"Orange Ug","numbering":"25679","price":"30"},
{"brand":"Safaricom Ke","numbering":"25470","price":"30"},
{"brand":"Safaricom Ke","numbering":"25471","price":"30"}];
var cdest = '245772306640,256754306640,25471624525,2567825689754,2563989654285,4588623566, 256782658974';
var dest = cdest.split(",");
// loop through brands and numbers.
//plan is to create create array like (brand1 =>countbrand1,brand2=>countbrand3, etc)
var cd = {};
for( var i=0; i<dest.length; i++ )
{
$.each(prices, function(index, m) {
// if(dest[i].toString().indexOf(m.numbering.toString()) != -1 )
//alert(dest[i].indexOf(m.numbering));
if(dest[i].toString().indexOf(m.numbering.toString()) == 0)
{
if( cd[m.brand] == undefined)
cd[m.brand] = 1;
else
cd[m.brand]+=1;
} //else
//cd[International]+=1;
});
}
for (var key in cd) {
alert(key + " = " + cd[key]);
}
In php arrays are used for many things, but in javascript arrays don't have keys. Objects do. What you have in the prices variable is an array of objects. To loop an object you can use the following syntax:
for (var key in p) {
// do something
// the key has the name `key` and to get the value, you
// can type p[key]
}
This is your inner loop. You got the outer loop right. This is how you will loop an array with the name dest:
for( var i=0; i<dest.length; i++ ) {
var member = dest[i];
// do something with member
}
With the outer loop we will get every object in the array and assign it to a variable with the name member. (You may think of a better name, of course)
So your final code will have to look something like this:
for( var i=0; i<dest.length; i++ ) {
var memeber = dest[i];
for (var key in member) {
// do something with the keys and values - print them for example.
}
}
Related
I am having trouble completing one of the last assignments in my semester-long high school-level programming class. I have been assigned to create a JavaScript program which counts the amount of time different ZIP codes appear in a set and output parallel arrays containing the zip codes and their counts. I am having difficulty getting the values to output. I believe that the respective zips and counts aren't being entered into their arrays at all.
I'm not looking for an original solution to the problem. I'd just like someone to tell me why my code isn't working, and possibly what I can change in my code specifically to fix it.
Usually I would never ask for help like this. I actually took the class last semester and now that I'm at the end of the year I have the option of completing it to earn college credit. I have never been the best at working with functions, and that remains true now. In the code below are all the moving parts I'm allowed to work with. I know it looks messy and rudimentary, but it's all I know. I'd appreciate it if any answers use only the sorts of things I used in my code. Another note, I am required to use functions for 'all identifiable processes', but I'm pretty sure my instructor only cares about the final product, so I'm not sure that the functions really matter, even if they could help.
var records = openZipCodeStudyRecordSet(),
uniqueZips = [],
zipCounts = [],
output = "";
function project62Part1() {
table = document.getElementById("outputTable");
function countZips(zip) {
var currentZip,
count;
while (records.readNextRecord()) {
currentZip = records.getSampleZipCode();
if (zip === currentZip) {
count++;
}
}
return count;
}
function processZip(zip) {
var currentZip;
while (records.readNextRecord()) {
currentZip = records.getSampleZipCode();
for (i = 0; i < uniqueZips.length; i++) {
if (uniqueZips[i] === "") {
uniqueZips.push(currentZip);
zipCounts[i] = countZips(currentZip);
break;
}
if (zip !== uniqueZip[i]) {
uniqueZips.push(currentZip);
zipCounts[i] = countZips(currentZip);
}
}
}
}
function createOutput(string) {
for (i = 0; i < uniqueZips.length; i++) {
string += "<tr><td>" + uniqueZips[i] + "</td><td>" + zipCounts[i] +
"</td></tr>";
}
return string;
}
processZip();
output = createOutput(output);
table.innerHTML = "<tr><td>Zip Code</td><td>Count</td></tr>" + output;
}
The output is supposed to be additional rows of zips and counts added to a table that is already set up on the page. There are no important technical errors in the code.
This is to be accomplished through the function processZip, which is meant to add respective zip and count into table rows. However, it appears as though the zip and count arrays its getting info from haven't had anything put into them by the other functions. I don't know if it is because of error in calling the functions, or what's in the functions themselves.
The HTML page this is connected to calls the function project62Part1().
That code is kind of all over the place but here's the logic you ideally want to follow:
Loop over each record in your table (outer loop) to get the zip code.
Declare an 'isFound' variable and set it to false
For each iteration of the outer loop, loop over your entire array of zip codes (inner loop).
3a. If you get a match, set isFound to true, increment your zipcode counter += 1 on the same index (since they're parallel arrays)
3b. If, at the end of your inner loop, isFound is still false, add the zipcode to your array of zip codes, and add a new array element to your zip code counters setting it to 1.
Since your zip code array and your zip code counter are parallel arrays to each other, when isFound is false, you are creating entries in both arrays, keeping them parallel to each other.
If, on 3a isFound is true, you are on the index of the zip code array that the zip code belongs to, so it should be the same index for your counter array.
In your current process zip function, the first condition will never be true, because starting out, your array size is 0 and after you start populating that array, you will never have an empty string (unless, of course, the zip code itself was an empty string)
The second if statement you have that checks if zip !== uniqueZip[i] - you are only checking that current value of uniqueZips and ignoring every other value in the array, so you will almost always have the second condition as true
I've been playing with the newer JavaScript language and syntax and your item was a good candidate for me to try out.
I did approach the code a little differently such as making the use of a Set for the unique values. Saves on code by not having to check and see if the value exists because the Set will never allow duplicate values in.
var uniqueZips = new Set();
const zipcodes = [21060, 22422, 25541, 43211, 21060, 22422, 22422, 43211, 43211, 43211];
function project62Part1() {
function processZipCodes() {
for(let index in zipcodes){
// We add every value because a SET will only allow you to add it once.
uniqueZips.add(zipcodes[index]);
}
}
// Structure our zipcode data information
function organizeZipCodeData() {
let response = {data:[]};
uniqueZips.forEach(function(zip) {
response.data.push( { 'zipcode':zip, 'appears': countZipAppearances(zip) })
});
return response;
}
function countZipAppearances(zip) {
// Default to zero even though you never expect an undefined
let count = 0;
zipcodes.forEach(function(zval) {
if (zip === zval) {
count++;
}
});
return count;
}
function showZipcodeInformation(data){
for (var index in data) {
if (data.hasOwnProperty(index)) {
var entry = [data[index]][0];
console.log(entry.zipcode, entry.appears);
}
}
}
// UI CONTENT: Construct the UI view from the data
function generateHtmlView(data){
let htmlview = "<table><tr><td>Zip Code</td><td>Count</td></tr>";
for (var index in data) {
if (data.hasOwnProperty(index)) {
var entry = [data[index]][0];
htmlview+="<tr><td>"+entry.zipcode+"</td><td>"+entry.appears+"</td></tr>";
}
}
htmlview += "</table>";
console.log(htmlview);
return htmlview;
}
// //////////////////////////////////////////////////////
// Call to gather the zipcodes
processZipCodes();
// Call to organize the zipcode data
let output = organizeZipCodeData();
// See what we have in the organized data
showZipcodeInformation(output.data);
// See what we have in the html content
generateHtmlView(output.data);
}
// Initiate the process
project62Part1();
I am relatively new to programming and am having some issues with a project I am working on.
msg.newCG2 = [];
for(i=0;i<msg.newCG.length;i++){
for(j=0;j<msg.campaignGroup.length;i++){
if(msg.campaignGroup[j].col10 === msg.newCG[j]){
msg.groupTotals = msg.groupTotals + msg.campaignGroup[j].col11;
}
msg.newCG2.push(msg.newCG[i], msg.groupTotals)
}
}
Basically, for each one of the "IDs" (integers) in msg.newCG, I want to look for each ID in msg.campaignGroup and sum up the totals for all listings with the same ID, from msg.campaignGroup.col11 - then push the ID and the totals to a new array - msg.newCG2.
When I run the code, the first item sent through processes, but grinds to a halt because of memory. I assume this is because of an error in my code.
Where did this code go wrong? I am sure that there are better ways to do this as a whole, but I am curious where I went wrong.
There is a typo in your second for loop and the push needs to happen inside the outer loop.
msg.newCG2 = [];
for(i=0;i<msg.newCG.length;i++){
for(j=0;j<msg.campaignGroup.length;j++){
if(msg.campaignGroup[j].col10 === msg.newCG[i]){
msg.groupTotals = msg.groupTotals + msg.campaignGroup[j].col11;
}
}
msg.newCG2.push(msg.newCG[i], msg.groupTotals)
}
How about:
msg.newCG2 = [];
for (i=0; i < msg.newCG.length; i++) {
var groupTotal = 0;
for (j=0; j < msg.campaignGroup.length; j++) {
if (msg.campaignGroup[j].col10 === msg.newCG[i]){
groupTotal = groupTotal + msg.campaignGroup[j].col11
}
}
msg.newCG2.push(groupTotal)
}
Rather than looping 1.2M times, it would be more efficient to use a single-pass over the 4000 campaign groups, grouping by id to create an array of totals for all ids -- I like using the reduce() function for this:
var cgMap = msg.campaignGroups.reduce(function(arr, grp) {
var grpid = grp.col10;
var count = grp.col11;
var total = arr[grpid] || 0;
arr[grpid] = total + count;
},
[]);
I know, the reduce(...) function is not the easiest to grok, but it takes the second arg (the empty array) and passes it, along with each campaign group object in turn, to that inline function. The result should be a simple array of group totals (from col11), indexed by the group id (from col10).
Now, it's just a matter of returning the totals for those 300 ids found in msg.newCG -- and this map() function does that for us:
var cgOut = msg.newCG.map(function(gid) {
return cgMap[gid]; // lookup the total by group id
}
);
I've made some assumptions here, like the group ids are not terribly large integers, and are rather closely spaced (not too sparse). From the original code, I was not able to determine the format of the data you are wanting to return in msg.newCG2. The final push() function would append 2 integers onto the array -- the output group id and the total for that group. Having pairs of group ids and totals interleaved in a flat array is not a very useful data structure. Perhaps you meant to place the total value into an array, indexed by the group id? If so, you could re-write that line as:
msg.newCG2[msg.newCG[i]] = msg.groupTotals;
I understand how to go about tasks using loops, recursion is kind of a mystery to me, but from what I understand in certain cases it can save a ton of time if looping through a lot of data.
I created the following function to loop through a large(ish) data set.
var quotes = require('./quotes.js');
//Pulls in the exported function from quotes.js
var exportedQuotes = quotes.allQuotes();
var allAuthors = exportedQuotes.author;
//Create an empty key value object, we use these to coerce unique values to an array
var uniqs = {};
//I create this object to hold all the authors and their quotes
var fullQuote = {};
//Create an object with only unique authors
for(var i = 0; i < allAuthors.length ; i++){
fullQuote[allAuthors[i]] = null;
}
//Coerce unique authors from javascript object into an array
var uniqAuthors = Object.keys(uniqs);
var quoteCount = exportedQuotes.author.length;
var iterativeSolution = function(){
for(var i = 0; i < Object.keys(fullQuote).length; i++){
for(var j = 0; j < exportedQuotes.author.length; j++){
//If the author in the unique list is equal to the author in the duplicate list
if(Object.keys(fullQuote)[i] == exportedQuotes.author[j]){
//if an author has not had a quote attributed to its name
if(fullQuote[exportedQuotes.author[j]] == null){
//assign the author an array with the current quote at the 0 index
fullQuote[exportedQuotes.author[j]] = [exportedQuotes.quote[j]]
} else {
//if an author already has a quote assigned to its name then just add the current quote to the authors quote list
fullQuote[exportedQuotes.author[j]].push(exportedQuotes.quote[j])
}
}
}
}
}
I don't currently have the skills to do analyze this, but, I'm wondering if there is a case for recursion to save the time it takes to get through all the loops. And if there is a case for recursion what does it look like for nested loops in javascript, specifically when creating key value objects recursively?
There may be a slight misunderstanding about what recursion is: recursion does not save time. It's just a different way of doing the same traversal. It generally a little easier to read, and depending on the problem, will map to certain algorithms better. However, one of the first things we do when we need to start optimizing code for speed is to remove recursion, turning them back into loops, and then even "unrolling" loops, making code much uglier, but fast, in the process. Recursion vs plain loops is almost always a matter of taste. One looks nicer, but that's hardly the only quality we should judge code on.
And also: just because it sounds like I'm advocating against using it, doesn't mean you shouldn't just try it: take that code, put it in a new file, rewrite that file so that it uses recursion. Doing so lets you compare your code. Which one is faster? Which is easier to read? Now you know something about how (your) code behaves, and you'll have learned something valuable.
Also don't sell yourself short: if you wrote this code, you know how it works, so you know how to analyze it enough to rewrite it.
Algorithms makes code fast or slow, not recursion. Some quite fast algorithms can use recursion, but that's a whole different story. Many algorithms can be written as both with recursion, and without recursion.
However, your code has a big problem. Notice how many times you call this code?
Object.keys(fullQuote)
You are re-computing the value of that many many times in your code. Don't do that. Just call it once and store in a variable, like the following:
var uniqAuthors = Object.keys(uniqs);
var uniqFullQuote = Object.keys(fullQuote);
var quoteCount = exportedQuotes.author.length;
//Loop through all quotes and assign all quotes to a unique author::Each author has many quotes
for(var i = 0; i < uniqFullQuote.length; i++){
for(var j = 0; j < exportedQuotes.author.length; j++){
//If the author in the unique list is equal to the author in the duplicate list
if(uniqFullQuote[i] == exportedQuotes.author[j]){
//if an author has not had a quote attributed to its name
if(fullQuote[exportedQuotes.author[j]] == null){
//assign the author an array with the current quote at the 0 index
fullQuote[exportedQuotes.author[j]] = [exportedQuotes.quote[j]]
} else {
//if an author already has a quote assigned to its name then just add the current quote to the authors quote list
fullQuote[exportedQuotes.author[j]].push(exportedQuotes.quote[j])
}
}
}
}
You don't have to iterate Object.keys(fullQuote).
var quotes = require('./quotes.js'),
exportedQuotes = quotes.allQuotes(),
allAuthors = exportedQuotes.author,
fullQuote = Object.create(null);
for(var i=0; i < allAuthors.length; ++i)
(fullQuote[allAuthors[i]] = fullQuote[allAuthors[i]] || [])
.push(exportedQuotes.quote[i])
I don't recommend recursion. It won't improve the asymptotic cost, and in JS calling functions is a bit expensive.
I got really curious and created a recursive solution just to see how it works. Then timed it, my iterative solution took 53 seconds to run, while my recursive solution took 1 millisecond to run. The iterative approach can obviously be tweaked based on the answers provided below, to run faster, but a recursive approach forced me to think in a "leaner" manner when creating my function.
var exportedQuotes = quotes.allQuotes();
var allAuthors = exportedQuotes.author;
var n = allAuthors.length
var fullQuote = {};
var recursiveSolution = function(arrayLength) {
//base case
if(arrayLength <= 1){
if(fullQuote[exportedQuotes.author[0]] == null){
fullQuote[exportedQuotes.author[0]] = [exportedQuotes.quote[0]];
}else{
fullQuote[exportedQuotes.author[0]].push(exportedQuotes.quote[0])
}
return;
};
//recursive step
if(fullQuote[exportedQuotes.author[arrayLength]] == null){
fullQuote[exportedQuotes.author[arrayLength]] = [exportedQuotes.quote[arrayLength]];
}else{
fullQuote[exportedQuotes.author[arrayLength]].push(exportedQuotes.quote[arrayLength])
}
newLength = arrayLength - 1;
return recursiveSolution(newLength);
}
////////Timing functions
var timeIteration = function(){
console.time(iterativeSolution);
iterativeSolution(); // run whatever needs to be timed in between the statements
return console.timeEnd(iterativeSolution);
}
var timeRecursive = function(){
console.time(recursiveSolution(n));
recursiveSolution(n); // run whatever needs to be timed in between the statements
return console.timeEnd(recursiveSolution(n));
}
I have a big question.
I have many Strings in my Programm and want to check these Strings on there values.
I wrote a Loop for it, but insted of the Definition of an String he is creating a new value. It's basicly really difficult to discribe, also because i am basicly German.
But i can give you my current code, so maybee you will see what I mean:
{
var Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
var Loch2G = $('#m1-Rundenanalyse-Turnier').val();
x=1
while (x <= 2) {
if ("Loch" + x + "G" == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1
}
}
How can I solve this?
I'd suggest using an array to store the values you want to check:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
for (var i = 0, len = lochs.length; i < len; i++){
if (lochs[i] == ''){
alert("Eingabe war leer");
}
}
JS Fiddle demos: passes (no alert), fails (alert)
This suggestion is based on my presumption that you're trying to create the names of the vars you want to check, which won't work, whereas this approach lets you store all values (however many) in the same array and then iterate over that array to find any values that are equal to an empty string.
If you really want to stick with your current approach, you could do the following:
{
window.Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
window.Loch2G = $('#m1-Rundenanalyse-Turnier').val();
var x=1;
while (x <= 2) {
if (window["Loch" + x + "G"] == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1;
}
}
But I can't think why you'd want to; plus the use of global variables is poor practice as it explicitly makes those variables available to every closure within the document, which allows them to be easily, and accidentally, overwritten.
In a reasonably up-to-date browser, that implements Array.prototype.every, you could dispense with the explicit iteration:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
if (!lochs.every(function(a){ return a !== ''; })) {
alert("Eingabe war leer");
}
JS Fiddle demos: passes (no alert), fails (alerts).
I have a JSON response like this:
var errorLog = "[[\"comp\",\"Please add company name!\"],
[\"zip\",\"Please add zip code!\"],
...
Which I'm deserializing like this:
var log = jQuery.parseJSON(errorLog);
Now I can access elements like this:
log[1][1] > "Please add company name"
Question:
If I have the first value comp, is there a way to directly get the 2nd value by doing:
log[comp][1]
without looping through the whole array.
Thanks for help!
No. Unless the 'value' of the first array (maybe I should say, the first dimension, or the first row), is also it's key. That is, unless it is something like this:
log = {
'comp': 'Please add a company name'
.
.
.
}
Now, log['comp'] or log.comp is legal.
There are two was to do this, but neither avoids a loop. The first is to loop through the array each time you access the items:
var val = '';
for (var i = 0; i < errorLog.length; i++) {
if (errorLog[i][0] === "comp") {
val = errorLog[i][1];
break;
}
}
The other would be to work your array into an object and access it with object notation.
var errors = {};
for (var i = 0; i < errorLog.length; i++) {
errors[errorLog[i][0]] = errorLog[i][1];
}
You could then access the relevant value with errors.comp.
If you're only looking once, the first option is probably better. If you may look more than once, it's probably best to use the second system since (a) you only need to do the loop once, which is more efficient, (b) you don't repeat yourself with the looping code, (c) it's immediately obvious what you're trying to do.
No matter what you are going to loop through the array somehow even it is obscured for you a bit by tools like jQuery.
You could create an object from the array as has been suggested like this:
var objLookup = function(arr, search) {
var o = {}, i, l, first, second;
for (i=0, l=arr.length; i<l; i++) {
first = arr[i][0]; // These variables are for convenience and readability.
second = arr[i][1]; // The function could be rewritten without them.
o[first] = second;
}
return o[search];
}
But the faster solution would be to just loop through the array and return the value as soon as it is found:
var indexLookup = function(arr, search){
var index = -1, i, l;
for (i = 0, l = arr.length; i<l; i++) {
if (arr[i][0] === search) return arr[i][1];
}
return undefined;
}
You could then just use these functions like this in your code so that you don't have to have the looping in the middle of all your code:
var log = [
["comp","Please add company name!"],
["zip","Please add zip code!"]
];
objLookup(log, "zip"); // Please add zip code!
indexLookup(log, "comp"); // Please add company name!
Here is a jsfiddle that shows these in use.
Have you looked at jQuery's grep or inArray method?
See this discussion
Are there any jquery features to query multi-dimensional arrays in a similar fashion to the DOM?