Parsing a JSON feed from YQL using jQuery - javascript

I am using YQL's query.multi to grab multiple feeds so I can parse a single JSON feed with jQuery and reduce the number of connections I'm making. In order to parse a single feed, I need to be able to check the type of result (photo, item, entry, etc) so I can pull out items in specific ways. Because of the way the items are nested within the JSON feed, I'm not sure the best way to loop through the results and check the type and then loop through the items to display them.
Here is a YQL (http://developer.yahoo.com/yql/console/) query.multi example and you can see three different result types (entry, photo, and item) and then the items nested within them:
select * from query.multi where queries=
"select * from twitter.user.timeline where id='twitter';
select * from flickr.photos.search where has_geo='true' and text='san francisco';
select * from delicious.feeds.popular"
or here is the JSON feed itself:
http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20query.multi%20where%20queries%3D%22select%20*%20from%20flickr.photos.search%20where%20user_id%3D'23433895%40N00'%3Bselect%20*%20from%20delicious.feeds%20where%20username%3D'keith.muth'%3Bselect%20*%20from%20twitter.user.timeline%20where%20id%3D'keithmuth'%22&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=
I am using jQuery's $.getJSON method

You don't need to parse JSON by hand. That's the point of JSON. Use JSON.parse(yourJSONstring) to convert it into a Javascript object.
Edit: Actually I'm not sure the browser support for that one. Here's the jQuery way:
http://api.jquery.com/jQuery.parseJSON/
Edit2:
var results = feedObj.query.results.results
for (var i = 0; i < results.length; i++) {
if (results[i].photo) {
// do something with photos
} else if (results[i].item) {
// do something with items
} else {
// do something with entry
}
}
Test for the existence of the results[i].photo object. If it exists, the result is an array which you can loop through and do something with.

Related

Understanding how to pull info from array

I have a previously created script that is doing API calls to get various info. Using json fetch. Its used to look up(GET) properties of users, groups, etc.
Here is how it prints. console.log(myArray):
[{user={conversion_id=smitht, ship_id=14.0, ship=Mountain , id=989, name=Smith, Todd, id=8745335.0, system_id=796663, login_id=todd.smith#domain.com,, created_at=3055-08-10, //keeps continuing for all users in this account
If I wanted to search the array and return only "name". Is there a better way to accomplish than this? This will print out just the names
for (let i = 0; i < myArray.length; i++){
console.log(myArray[i]['user']['name'])
I'm trying to learn what's possible and how to interact. Any other options to search through array? Most examples have sample arrays written out since mine comes from a response its been difficult to follow those examples.
use find https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find
function findByLoginId(loginId) {
const result = myArray.find(user => user.login_id === loginId);
return result?.name;
}
Check to make sure that the fetched data is valid JSON. You should be able to use JSON.parse on the returned data.

Iterate once and perform many actions or iterate for every action in JavaScript

I have a .txt file with a lot of data that I'd like to analyze. It's a long string containing multiple lines with a date, a person and a message, finishing with an end of line. I already managed to get an array of the strings using .split("\n") and created a function that parses the line into an object with my desired properties.
Now, I need to obtain data like how many messages per person, how many messages in a year, but I only need to do this once, when I load the file.
Should I iterate through the array of objects for each query after parsing?
messageByPerson(array) {
for (let i = 0; i < array.length; i++) {
// Count the messages
}
}
Or should I create a data structure for each query and update the count when parsing in the main loop?
messagesByPerson = [{
person: 'example',
count: 23
}, ...]
Note that:
The file can be quite big and contain 200k+ lines.
Can not use a remote database to store any data.

Updating MongoDB array from variable array in batch operation?

I am working in Node.js and am attempting to push or pull the contents of an array to my mongodb collection. Currently my [working] code to pull objects from the array in FieldArray looks something like this:
for (var i=0; i < MyList.length; i++) {
collection.update(
{field:"MyValue"},
{$pull: {FieldArray: MyList[i]}},
function(err, item){...}
);
}
I'm aware of the ability to use $push/$each, $addToSet/$each and $pullall but they don't seem to accept values dynamically from an array (or I haven't found any indication that it can). Basically, I'd like to be able to use this function with an array of one item or one hundred, using the appropriate batch calls.
Is there any way to make such a call without having to loop through a separate call on the database for each iteration?
You want $pullAll. It does exactly what you are trying to iterate over
collection.update(
{ "field": "MyValue" },
{ "$pullAll": { "FieldArray": MyList } }
)
If that doesn't work then then your array elements are not matching the structure used in your document. Make them that way.

json jquery filter javascript array

I have a json object array. I want to search the array and for each object, create a list of 'services' that is a comma-seperated list of all the keys which have a value of "yes".
The list of json objects with the services list is then displayed in html using jquery's each.
Its a large json file so I want to do it as efficiently as possible.
I already have the object's properties being accessed through jQuery's each (ie, obj.name)
-- so I think it should be possible to filter the services listed for each object using
jQuery's filter, and then display the key if the value is yes.
But it seems like a more efficient option would probably be to create a new javascript array, join the services with a value of yes and then add that variable to the html being
appended.
Im not sure which would be faster and so far havent been very successful at either... so any advice and examples would be very helpful.
Here's what the json array looks like:
[
{"name":"name1",
"service1":"y",
"service2":"y",
"service3":"n",
},
{"name":"name2",
"service1":"n",
"service2":"y",
"service3":"n",
},
];
If you just want to filter the array then use grep.
grep - Finds the elements of an array which satisfy a filter function. The original array is not affected.
http://api.jquery.com/jQuery.grep/
First off, delete trailing commas. Internet Explorer gets really, really confused by them. Anyway, I assume you don't want to "search" the array when you say "for each value"; you want to iterate through the array and parse it into a more usable list. The first method I'd suggest is just passing what you want as the array you desire, but if that's not an option, what you're looking for is some variant of this, which should be fairly efficient (jsFiddle example):
var json = [
{"name":"name1", "service1":"y", "service2":"y", "service3":"n"},
{"name":"name2", "service1":"n", "service2":"y", "service3":"n"}
];
var parsed = {};
for (var i = 0, iLen = json.length; i < iLen; i++) {
// Assuming all we need are the name and a list
var name;
var list = [];
for (var key in json[i]) {
var value = json[i][key];
// We need to hold on to the name or any services with value "y"
if (key === "name") {
name = value;
} else if (value === "y") {
list.push(key);
}
}
// Add them to the parsed array however you'd like
// I'm assuming you want to just list them in plain text
parsed[name] = list.join(", ");
}
// List them on the web page
for (var key in parsed) {
document.write(key + ": " + parsed[key] + "<br>");
}
That way you wind up with a display to the visitor of the services available and still keep an array around for further use if necessary.
jQuery.inArray() Search for a specified value within an array and return its index (or -1 if not found).
http://api.jquery.com/jQuery.inArray/
Or
http://api.jquery.com/jQuery.each/

How do I scan JSON with jquery to determine the number of instances of a certain string?

I have some JSON which looks generally like this...
{"appJSON": [
{
"title":"Application Title",
"category":"Business",
"industry":"Retail",
"language":"English",
"tags":[
{"tags":"Sales"},{"tags":"Reporting"},{"tags":"Transportation"},{"tags":"Hospitality"}
],
},
{
"title":"Airline Quality Assurance",
...
...
...]}
I'm looping through JSON to get an array of all of the unique Tags in the data.
My question is, now that I have an array of the different unique Tags in the JSON, how do I best determine the number of times each Tag occurs?
So basically I'm looking to generate a list of all of the tags found in the JSON (which I already have) with the number of times each one occurs (which I don't already have).
Thanks a lot in advance!
I'm assuming when you find a new tag you check to see if you already have that tag somewhere. If you don't you add it to your list. Why not when you check do something like.
var nextTag=//get the next tag in the JSON list
var newTag=true;
for(var i=0;i<tags.length;i++){
if(nextTag === tags[i]){
tagCount[i]++;
newTag=false;
break;
}
}
if(newTag){
tags[tags.length]=nextTag;
tagCount[tagCount.length]=1;
}
This uses two arrays where tagCount[i] is the number of times tag in tags[i] occurs. You could uses an object to do this or however you wanted to.
As an alternative, here's a function which will fill an associative array; the keys will be the tags and the values will be the number of occurrences of that tag.
var tagCounts = []; // Global variable here, but could be an object property or any array you like really
function countTags(tags, tagCounts)
{
$.each(tags, function(i, item) {
var tag = item.tags; // This would change depending on the format of your JSON
if(tagCounts[tag] == undefined) // If there's not an index for this tag
tagCounts[tag] = 0;
tagCounts[tag]++;
});
}
So you can call this function on any number of arrays of tags, passing in your tagCounts (totals) array, and it will aggregate the totals.
var tags1 = [{"tags":"Sales"},{"tags":"Reporting"},{"tags":"Transportation"},{"tags":"Hospitality"}];
var tags2 = [{"tags":"Reporting"},{"tags":"Transportation"}];
var tags3 = [{"tags":"Reporting"},{"tags":"Hospitality"}];
countTags(tags1, tagCounts);
countTags(tags2, tagCounts);
countTags(tags3, tagCounts);
Then you can read them out like so:
for(var t in tagCounts)
// t will be the tag, tagCounts[t] will be the number of occurrences
Working example here: http://jsfiddle.net/UVUrJ/1/
qw3n's answer is actually a more efficient way of doing things, as you're only looping through all the tags onceā€”but unless you have a really huge JSON source the difference isn't going to be noticeable.

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