I have an array of subscription instances #subscription_valids and an array of subscribed player that look like that :
array_subscribed_players = [{"name0" => "link1"}, {"name1"=>"link2"}, {"name2"=>"link3"}....]
What I need to do is : for each subscription in #subscription_valids :
#subscription_valids.each do |subscription|
I need to check if subscription.user.full_name or if subscription.user.full_name_inversed matches a key in one of the hashes of array_subscribed_player (in the exemple "name0", "name1" or "name2").
If it matches then I should store the relevant subscription as key in a hash in a new array and extract the relevant link as value of this hash. My final outpout should be an array that looks like this :
[{subscription1 => "link1"}, {subscription2 => "link2}, ...]
else if the subscription.user.full_name doesnt match i'll just store the subscription in a failure array.
How can I achieve this result ?
See http://ruby-doc.org/core-2.2.3/Hash.html
A user-defined class may be used as a hash key if the hash and eql?
methods are overridden to provide meaningful behavior. By default,
separate instances refer to separate hash keys.
so I think you should override your .eql? method in #subscription_valids to something meaningful (like a unique string)
I can't think for a Array method so you can go like:
demo
results = []
failures = []
#subscription_valids.each do |subscription|
array_subscribed_players.each do |player|
if player.keys.first == subscription.user.full_name || player.keys.first == subscription.user.full_name_inversed
results << { subscription => player[player.keys.first] }
else
failures << subscription
end
end
end
You can try the following:
valid = array_subscribed_players.select{|x| #subscription_valids.map(&:name).include?(x.keys.first)}
Demo
If you need to store both valid and invalid values somewhere:
valid, invalid = array_subscribed_players.partition{|x| #subscription_valids.map(&:name).include?(x.keys.first)}
Related
I have two arrays, one containing 200.000 product objects coming from a CSV file and one containing 200.000 product objects coming from a database.
Both arrays contains objects with the same fields, with one exception: the database objects have a unique ID as well.
I need to compare all 200.000 CSV objects with the 200.000 database objects. If the CSV object already exists in the database objects array I put it in an "update" array together with the ID from the match, and if it doesn't, then I put it in a "new" array.
When done, I update all the "update" objects in the database, and insert all the "new" ones. This goes fast (few seconds).
The compare step however takes hours. I need to compare three values: the channel (string), date (date) and time (string). If all three are the same, it's a match. If one of those isn't, then it's not a match.
This is the code I have:
const newProducts = [];
const updateProducts = [];
csvProducts.forEach((csvProduct) => {
// check if there is a match
const match = dbProducts.find((dbProduct) => {
return dbProduct.channel === csvProduct.channel && moment(dbProduct.date).isSame(moment(csvProduct.date), 'day') && dbProduct.start_time === csvProduct.start_time;
});
if (match) {
// we found a match, add it to updateProducts array
updateProducts.push({
id: match.id,
...csvProduct
});
// remove the match from the dbProducts array to speed things up
_.pull(dbProducts, match);
} else {
// no match, it's a new product
newProducts.push(csvProduct);
}
});
I am using lodash and moment.js libraries.
The bottleneck is in the check if there is a match, any ideas on how to speed this up?
This is a job for the Map collection class. Arrays are a hassle because they must be searched linearly. Maps (and Sets) can be searched fast. You want to do your matching in RAM rather than hitting your db for every single object in your incoming file.
So, first read every record in your database and construct a Map where the keys are objects like this {start_time, date, channel} and the values are id. (I put the time first because I guess it's the attribute with the most different values. It's an attempt to make lookup faster.)
Something like this pseudocode.
const productsInDb = new Map()
for (const entry in database) {
const key = { // make your keys EXACTLY the same when you load your Map ..
start_time: entry.start_time,
date: moment(entry.date),
entry.channel}
productsInDb.add(key, entry.id)
}
This will take a whole mess of RAM, but so what? It's what RAM is for.
Then do your matching more or less the way you did it in your example, but using your Map.
const newProducts = [];
const updateProducts = [];
csvProducts.forEach((csvProduct) => {
// check if there is a match
const key = { // ...and when you look up entries in the Map.
start_time: entry.start_time,
date: moment(entry.date),
entry.channel}
const id = productsInDb.get(key)
if (id) {
// we found a match, add it to updateProducts array
updateProducts.push({
id: match.id,
...csvProduct
});
// don't bother to update your Map here
// unless you need to do something about dups in your csv file
} else {
// no match, it's a new product
newProducts.push(csvProduct)
}
});
The problem with the ECMA standard for sort of Object.keys() is known:
Object.keys() handle all keys with integer (example: 168), including integer as strings (example: "168"), as a integer. The result is, both are the same (168 === "168"), and overwrite itself.
var object = {};
object["168"] = 'x';
object[168] = 'y';
Object.keys(object); // Array [ "168" ]
object[Object.keys(object)]; // "y"
Interestingly, all keys (including pure integer keys) are returned as a string.
The ecma262 wrote about this: All keys will be handle as a integer, expect the key is a String but is not an array index.
https://tc39.es/ecma262/#sec-ordinaryownpropertykeys
That should tell us: 168 === "168". A toString() do not solve the problem.
var object = {};
object[[3].toString()] = 'z';
object[[1].toString()] = 'x';
object[[2].toString()] = 'y';
Object.keys(object);
// Array(3) [ "1", "2", "3" ]
Paradoxically, in this case, only integer apply as "enumerable" (it's ignoring array.sort(), that sort also strings with letters.).
My question about this is simple: How can i prevent the sort function in Object.keys()? I have testet the Object.defineProperties(object, 1, {value: "a", enumerable: true/false}), but that mean not realy enumerable in the case of integer or string or integer-like string. It means only should it be counted with or not. It means "counted" like omit (if it false), not "enumerabled" like ascending or descending.
A answere like that is not a good answer: Please use only letters [a-zA-Z] or leastwise a letter at the first position of keyword.
What I want: That the keys are not sorted, but output in the order in which they were entered, whether integer, string or symbol.
Disclaimer: Please solutions only in JavaScript.
Javascript Objects are unordered by their nature. If you need an ordered object-like variable I would suggest using a map.
To achieve what you're looking for with a map instead of object you'd do something like the below:
var map1 = new Map();
map1.set("123", "c");
map1.set(123, "b");
var iterator1 = map1.keys();
var myarray = [];
for (var i = 0; i < map1.size; i++) {
myarray.push(iterator1.next().value);
}
console.log(myarray);
// Array ["123", 123]
Unfortunately it's not compatible with IE and I'm not sure how else you could achieve what you need without it. A quick Google did return something about jQuery maps, though.
If you don't want to use jQuery and still need to support IE some points are below:
Is there anything stopping you using an array rather than JS object to store the data you need? This will retain the order per your requirements unlike objects. You could have an object entry in each iteration which represents the key then use a traditional foreach to obtain them as an array. I.e.
The array:
var test_array = [
{key: 123, value: 'a value here'},
{key: "123", value: 'another value here'}
];
// console.log(test_array);
Getting the keys:
var test_array_keys = [];
test_array.forEach(function(obj) { test_array_keys.push(obj['key']); } );
// console.log(test_array_keys);
Then if you needed to check whether the key exists before adding a new entry (to prevent duplicates) you could do:
function key_exists(key, array)
{
return array.indexOf(key) !== -1;
}
if(key_exists('12345', test_array_keys))
{
// won't get here, this is just for example
console.log('Key 12345 exists in array');
}
else if(key_exists('123', test_array_keys))
{
console.log('Key 123 exists in array');
}
Would that work? If not then the only other suggestion would be keeping a separate array alongside the object which tracks the keys and is updated when an entry is added or removed to/from the object.
Object Keys sorted and store in array
First Creating student Object. then sort by key in object,last keys to store in array
const student={tamil:100, english:55, sci:85,soc:57}
const sortobj =Object.fromEntries(Object.entries(student).sort())
console.log(Object.keys(sortobj))
use map instead of an object.
let map = new Map()
map.set("a", 5)
map.set("d", 6)
map.set("b", 12)
to sort the keys (for example, to update a chart data)
let newMap = new Map([...map.entries()].sort())
let keys = Array.from(newMap.keys()) // ['a','b','d']
let values = Array.from(newMap.values()) // [5,12,6]
I have multiple objects that all have the same keys lets say each object has: name and position. The first object will start with position=0. The second object would have position=1. The third object would have position=2 and so on until we get to the 10th object that would have position=9.
I need a way to subtract 1 from every objects position (with only possible values being 0-9 so that 0-1=9)
Looking for a solution that handles all of them mathematically at once, not just re-writing out new values to assign to each key individually.
Suppose you have an array of JavaScript objects, you could use map:
var newObjs = objects.map(function (object) {
object.position = (object.position === 9 ? 0 : object.position--);
return object;
});
A better approach would be:
objects.forEach( function (object) {
object.position--;
object.position = object.position < 0 ? 9 : object.position;
});
I have an array and want to fetch some values from array which has Strings as key.Please suggest how can i retrieve those values from array have string as key.
Code for Controller is:
var ultColumn=undefined;
$scope.ultColm="Attained Age";
for(var i=0;i<5;i++){
ultColumn=ultrowCellData[i][$scope.ultColmn];//This is not working
}//ultrowCellData contains the array
Please suggest how to get the value of key "Attained Age"
You can use angular.forEach(); For example:
angular.forEach(yourArray, function(value, key){
if(typeof key === 'string'){
console.log("Your result is here :", value);
}
});
Thanks.
If screenshot which you provided shows data included in ultrowCellData then it is not an array but map - var something = ultrowCellData['Attained Age '] will assign value 28 to something
You seem to have forgotten a space at the end of your key, on line 2.
Try Attained Age<space> instead of Attained Age (replace <space> with an actual space).
Notice, though, that this is a non-standard use for an Array, as arrays usually use only numbers as keys.
if at all possible, try using an Object instead.
I have an array, lets call it _persons.
I am populating this array with Value Objects, lets call this object PersonVO
Each PersonVO has a name and a score property.
What I am trying to do is search the array &
//PSEUDO CODE
1 Find any VO's with same name (there should only be at most 2)
2 Do a comparison of the score propertys
3 Keep ONLY the VO with the higher score, and delete remove the other from the _persons array.
I'm having trouble with the code implementation. Any AS3 wizards able to help?
You'd better use a Dictionary for this task, since you have a designated unique property to query. A dictionary approach is viable in case you only have one key property, in your case name, and you need to have only one object to have this property at any given time. An example:
var highscores:Dictionary;
// load it somehow
function addHighscore(name:String,score:Number):Boolean {
// returns true if this score is bigger than what was stored, aka personal best
var prevScore:Number=highscores[name];
if (isNaN(prevScore) || (prevScore<score)) {
// either no score, or less score - write a new value
highscores[name]=score;
return true;
}
// else don't write, the new score is less than what's stored
return false;
}
The dictionary in this example uses passed strings as name property, that is the "primary key" here, thus all records should have unique name part, passed into the function. The score is the value part of stored record. You can store more than one property in the dictionary as value, you'll need to wrap then into an Object in this case.
you want to loop though the array and check if there are any two people with the same name.
I have another solution that may help, if not please do say.
childrenOnStage = this.numChildren;
var aPerson:array = new array;
for (var c:int = 0; c < childrenOnStage; c++)
{
if (getChildAt(c).name == "person1")
{
aPerson:array =(getChildAt(c);
}
}
Then trace the array,