Ques: I want to filter list within a list. All of my data models are immutable.
My JSON structure looks like this
{
"root": [
{
"id": 2,
"val": 1231.12,
"fruit": [
{
"id": 2,
"name": "apple"
}
]
},
{
"id": 3,
"val": 1231.12,
"fruit": [
{
"id": 2,
"name": "apple"
},
{
"id": 3,
"name": "orange"
}
]
}
],
"fruits": [
{
"id": 1,
"name": "apple"
},
{
"id": 2,
"name": "guava"
},
{
"id": 3,
"name": "banana"
}
]
}
Problem Statement - Basically, I want to create a list of all items of root where fruit name is apple. Currently, my naive solution looks like this. This involves creating a temporary mutuable list and then add specific items to it.
Below solution works fine but is there any other better way to achieve the same.
val tempList = arrayListOf<RootItem>()
root?.forEach { item ->
item.fruit.filter {
// filter condition
it.id != null && it.name == "apple"
}
testList.add(item)
}
A combination of filter and any will do the work:
val result = root?.filter { item ->
item.fruits.any { it.id != null && it.name == "apple" }
}
BTW: Your solution will not work. The filter function does return a new list, that you are not using. And you always add the item to the list, not only if the predicate returns true.
Related
How can i get the value by id from a array in vue js? Many thanks with solution
list = [
{
"name": "Apple",
"id": 1,
},
{
"name": "Orange",
"id": 2,
}
]
watch: {
food: function (val) {
//Get food name by val(id)
}
}
Use Array.find method, which returns the value of the first element in the array that satisfies the provided testing function:
var food = list.find(food => food.id === val)
var name = food ? null : food.name
let list = [
{
"name": "Apple",
"id": 1,
},
{
"name": "Orange",
"id": 2,
}
]
console.log(
list.find(food => food.id === 1).name
)
I have following documents in azure cosmos db collection.
// Document 1
{
"c": {
"firstName": "Robert"
}
"elements" : [
{
"a": "x2",
"b": {
"name": "yadda2",
"id": 1
}
}
]
}
// Document 2
{
"c": {
"firstName": "Steve"
}
"elements" : [
{
"a": "x5",
"b": {
"name": "yadda2",
"id": 4
}
},
{
"a": "x3",
"b": {
"name": "yadda8",
"id": 5
}
},
]
}
// Document 3
{
"c": {
"firstName": "Johnson"
}
"elements" : [
{
"a": "x4",
"b": {
"name": "yadda28",
"id": 25
}
},
{
"a": "x5",
"b": {
"name": "yadda30",
"id": 37
}
},
]
}
I need to write a query that returns all documents which have "b" object whose name is "yadda2" (i.e. /elements/*/b/name=yadda2). In other words, this query should return document 1 and 2 but NOT 3.
I tried following but it did not work:
SELECT * FROM x where ARRAY_CONTAINS(x.elements, {b: { name: "yadda2"}})
What am I doing wrong?
Just modify your sql to :
SELECT * FROM x where ARRAY_CONTAINS(x.elements, {b: { name: "yadda2"}},true)
Result:
Based on the official doc , the boolean expression could specify if the match is full or partial.
Hope it helps you.
I have json data similar to this:
{
"Sections": [
{
"Categories": [
{
"Name": "Book",
"Id": 1,
"Options": [
{
"Name": "AAAA",
"OptionId": 111
},
"Selected": 0
},
{
"Name": "Car",
"Id": 2,
"Options": [
{
"Name": "BBB",
"OptionId": 222
},
"Selected": 0
},
],
"SectionName": "Main"
},
... more sections like the one above
]
}
Given this data, I want to find a category inside a section based on its (Category) Id, and set its selected option, I tried this, but couldn't get it to work....Note Category Id will be unique in the whole data set.
_.find(model.Sections, { Categories: [ { Id: catId } ]});
According to your data model, it looks like you're trying to find an element that is inside a matrix: Sections can have multiple Categories and a Category can have multiple types (car, book...).
I'm afraid there isn't a function in lodash that allows a deep find, you'll have to implement it the 'traditional' way (a couple of fors).
I provide this solution that is a bit more 'functional flavoured' than the traditional nested fors. It also takes advantage of the fact that when you explicitly return false inside a forEach, the loop finishes. Thus, once an element with the provided id is found, the loop is ended and the element returned (if it's not found, undefined is returned instead).
Hope it helps.
const findCategoryById = (sections, id) => {
var category;
_.forEach(sections, (section) => {
category = _.find(section.Categories, ['Id', id]);
return _.isUndefined(category);
});
return category;
};
const ex = {
"Sections": [{
"Categories": [{
"Name": "Book",
"Id": 1,
"Options": [{
"Name": "AAAA",
"OptionId": 111
}],
"Selected": 0
},
{
"Name": "Car",
"Id": 2,
"Options": [{
"Name": "BBB",
"OptionId": 222
}],
"Selected": 0
}
],
"SectionName": "Main"
}]
};
console.log(findCategoryById(ex.Sections, 2));
<script src="https://cdn.jsdelivr.net/npm/lodash#4.17.5/lodash.min.js"></script>
I'm new in lodash (v3.10.1), and having a hard time understanding.
Hope someone can help.
I have an input something like this:
{
{"id":1,"name":"Matthew","company":{"id":1,"name":"abc","industry":{"id":5,"name":"Medical"}}},
{"id":2,"name":"Mark","company":{"id":1,"name":"abc","industry":{"id":5,"name":"Medical"}}},
{"id":3,"name":"Luke","company":{"id":1,"name":"abc","industry":{"id":5,"name":"Medical"}}},
{"id":4,"name":"John","company":{"id":1,"name":"abc","industry":{"id":5,"name":"Medical"}}},
{"id":5,"name":"Paul","company":{"id":1,"name":"abc","industry":{"id":5,"name":"Medical"}}}
];
I would like to output this or close to this:
{
"industries": [
{
"industry":{
"id":5,
"name":"Medical",
"companies": [
{
"company":{
"id":1,
"name":"abc",
"employees": [
{"id":1,"name":"Matthew"},
{"id":2,"name":"Mark"},
{"id":3,"name":"Luke"},
{"id":4,"name":"John"},
{"id":5,"name":"Paul"}
]
}
}
]
}
}
]
}
Here's something that gets you close to what you want. I structured the output to be an object instead of an array. You don't need the industries or industry properties in your example output. The output structure looks like this:
{
"industry name": {
"id": "id of industry",
"companies": [
{
"company name": "name of company",
"id": "id of company",
"employees": [
{
"id": "id of company",
"name": "name of employee"
}
]
}
]
}
}
I use the _.chain function to wrap the collection with a lodash wrapper object. This enables me to explicitly chain lodash functions.
From there, I use the _.groupBy function to group elements of the collection by their industry name. Since I'm chaining, I don't have to pass in the array again to the function. It's implicitly passed via the lodash wrapper. The second argument of the _.groupBy is the path to the value I want to group elements by. In this case, it's the path to the industry name: company.industry.name. _.groupBy returns an object with each employee grouped by their industry (industries are keys for this object).
I then do use _.transform to transform each industry object. _.transform is essentially _.reduce except that the results returned from the _.transform function is always an object.
The function passed to the _.transform function gets executed against each key/value pair in the object. In the function, I use _.groupBy again to group employees by company. Based off the results of _.groupBy, I map the values to the final structure I want for each employee object.
I then call the _.value function because I want to unwrap the output collection from the lodash wrapper object.
I hope this made sense. If it doesn't, I highly recommend reading Lo-Dash Essentials. After reading the book, I finally got why lodash is so useful.
"use strict";
var _ = require('lodash');
var emps = [
{ "id": 1, "name": "Matthew", "company": { "id": 1, "name": "abc", "industry": { "id": 5, "name": "Medical" } } },
{ "id": 2, "name": "Mark", "company": { "id": 1, "name": "abc", "industry": { "id": 5, "name": "Medical" } } },
{ "id": 3, "name": "Luke", "company": { "id": 1, "name": "abc", "industry": { "id": 5, "name": "Medical" } } },
{ "id": 4, "name": "John", "company": { "id": 1, "name": "abc", "industry": { "id": 5, "name": "Medical" } } },
{ "id": 5, "name": "Paul", "company": { "id": 1, "name": "abc", "industry": { "id": 5, "name": "Medical" } } }
];
var result = _.chain(emps)
.groupBy("company.industry.name")
.transform(function(result, employees, industry) {
result[industry] = {};
result[industry].id = _.get(employees[0], "company.industry.id");
result[ industry ][ 'companies' ] = _.map(_.groupBy(employees, "company.name"), function( employees, company ) {
return {
company: company,
id: _.get(employees[ 0 ], 'company.id'),
employees: _.map(employees, _.partialRight(_.pick, [ 'id', 'name' ]))
};
});
return result;
})
.value();
Results from your example are as follows:
{
"Medical": {
"id": 5,
"companies": [
{
"company": "abc",
"id": 1,
"employees": [
{
"id": 1,
"name": "Matthew"
},
{
"id": 2,
"name": "Mark"
},
{
"id": 3,
"name": "Luke"
},
{
"id": 4,
"name": "John"
},
{
"id": 5,
"name": "Paul"
}
]
}
]
}
}
If you ever wanted the exact same structure as in the questions, I solved it using the jsonata library:
(
/* lets flatten it out for ease of accessing the properties*/
$step1 := $ ~> | $ |
{
"employee_id": id,
"employee_name": name,
"company_id": company.id,
"company_name": company.name,
"industry_id": company.industry.id,
"industry_name": company.industry.name
},
["company", "id", "name"] |;
/* now the magic begins*/
$step2 := {
"industries":
[($step1{
"industry" & $string(industry_id): ${
"id": $distinct(industry_id)#$I,
"name": $distinct(industry_name),
"companies": [({
"company" & $string(company_id): {
"id": $distinct(company_id),
"name": $distinct(company_name),
"employees": [$.{
"id": $distinct(employee_id),
"name": $distinct(employee_name)
}]
}
} ~> $each(function($v){ {"company": $v} }))]
}
} ~> $each(function($v){ {"industry": $v} }))]
};
)
You can see it in action on the live demo site: https://try.jsonata.org/VvW4uTRz_
I'm using elasticsearch and need to implement facet search for hierarchical object as follow:
category 1 (10)
subcategory 1 (4)
subcategory 2 (6)
category 2 (X)
...
So I need to get facets for two related objects. Documentation says that it's possible to get such kind of facets for numeric value, but I need it for strings http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-facets-terms-stats-facet.html
Here is another interesting topic, unfortunately it's old: http://elasticsearch-users.115913.n3.nabble.com/Pivot-facets-td2981519.html
Does it possible with elastic search?
If so, how can I do that?
The previous solution works really well until you have no more than a multi-level tag on a single-document. In this case a simple aggregation doesn't work, because the flat structure of the lucene fields mix the results on the internal aggregation.
See the example below:
DELETE /test_category
POST /test_category
# Insert a doc with 2 hierarchical tags
POST /test_category/test/1
{
"categories": [
{
"cat_1": "1",
"cat_2": "1.1"
},
{
"cat_1": "2",
"cat_2": "2.2"
}
]
}
# Simple two-levels aggregations query
GET /test_category/test/_search?search_type=count
{
"aggs": {
"main_category": {
"terms": {
"field": "categories.cat_1"
},
"aggs": {
"sub_category": {
"terms": {
"field": "categories.cat_2"
}
}
}
}
}
}
That's the WRONG response that I have got on ES 1.4, where the fields on the internal aggregation are mixed at a document level:
{
...
"aggregations": {
"main_category": {
"buckets": [
{
"key": "1",
"doc_count": 1,
"sub_category": {
"buckets": [
{
"key": "1.1",
"doc_count": 1
},
{
"key": "2.2", <= WRONG
"doc_count": 1
}
]
}
},
{
"key": "2",
"doc_count": 1,
"sub_category": {
"buckets": [
{
"key": "1.1", <= WRONG
"doc_count": 1
},
{
"key": "2.2",
"doc_count": 1
}
]
}
}
]
}
}
}
A Solution can be to use nested objects. These are the steps to do:
1) Define a new type in the schema with nested objects
POST /test_category/test2/_mapping
{
"test2": {
"properties": {
"categories": {
"type": "nested",
"properties": {
"cat_1": {
"type": "string"
},
"cat_2": {
"type": "string"
}
}
}
}
}
}
# Insert a single document
POST /test_category/test2/1
{"categories":[{"cat_1":"1","cat_2":"1.1"},{"cat_1":"2","cat_2":"2.2"}]}
2) Run a nested aggregation query:
GET /test_category/test2/_search?search_type=count
{
"aggs": {
"categories": {
"nested": {
"path": "categories"
},
"aggs": {
"main_category": {
"terms": {
"field": "categories.cat_1"
},
"aggs": {
"sub_category": {
"terms": {
"field": "categories.cat_2"
}
}
}
}
}
}
}
}
That's the response, now correct, that I have got:
{
...
"aggregations": {
"categories": {
"doc_count": 2,
"main_category": {
"buckets": [
{
"key": "1",
"doc_count": 1,
"sub_category": {
"buckets": [
{
"key": "1.1",
"doc_count": 1
}
]
}
},
{
"key": "2",
"doc_count": 1,
"sub_category": {
"buckets": [
{
"key": "2.2",
"doc_count": 1
}
]
}
}
]
}
}
}
}
The same solution can be extended to a more than two-levels hierarchy facet.
Currently, elasticsearch does not support hierarchical facetting out-of-the-box. But the upcoming 1.0 release features a new aggregations module, that can be used to get these kind of facets (which are more like pivot-facets rather than hierarchical facets). Version 1.0 is currently in beta, you can download the second beta and test out aggregatins by yourself. Your example might look like
curl -XPOST 'localhost:9200/_search?pretty' -d '
{
"aggregations": {
"main category": {
"terms": {
"field": "cat_1",
"order": {"_term": "asc"}
},
"aggregations": {
"sub category": {
"terms": {
"field": "cat_2",
"order": {"_term": "asc"}
}
}
}
}
}
}'
The idea is, to have a different field for each level of facetting and bucket your facets based on the terms of the first level (cat_1). These aggregations then would have sub-buckets, based on the terms of the second level (cat_2). The result may look like
{
"aggregations" : {
"main category" : {
"buckets" : [ {
"key" : "category 1",
"doc_count" : 10,
"sub category" : {
"buckets" : [ {
"key" : "subcategory 1",
"doc_count" : 4
}, {
"key" : "subcategory 2",
"doc_count" : 6
} ]
}
}, {
"key" : "category 2",
"doc_count" : 7,
"sub category" : {
"buckets" : [ {
"key" : "subcategory 1",
"doc_count" : 3
}, {
"key" : "subcategory 2",
"doc_count" : 4
} ]
}
} ]
}
}
}