How can I filter the current data:
[{
key: 'T1',
legs:[{ fno: 'W321',date: '2017-01-02 18:20:00.000+0200'}],
fare: { type: 'B', price: 25 }
},{
key: 'T1',
legs:[{ fno: 'W321', date: '2017-01-02T18:20:00.000+0200'}],
fare: { type: 'E', price: 23 }
},{
key: 'T1',
legs:[{ fno: 'W321', date: '2017-01-02T18:20:00.000+0200'}],
fare: { type: 'E', price: 20}
}]
I want to group by legs[0].fno, legs[0].date and fare.type, and keep the lowest priced items in each group. This is the expected result:
[{
key: 'T1',
legs:[{ fno: 'W321',date: '2017-01-02T18:20:00.000+0200'}],
fare: { type: 'B', price: 25}
},{
key: 'T1',
legs:[{ fno: 'W321',date: '2017-01-02T18:20:00.000+0200'}],
fare: { type: 'E', price: 20}
}]
Use _.groupBy() with a callback to create a string to group by, then _.map() each group to a single item using _.minBy():
var data = [{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02 18:20:00.000+0200"}],"fare":{"type":"B","price":25}},{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02T18:20:00.000+0200"}],"fare":{"type":"E","price":23}},{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02T18:20:00.000+0200"}],"fare":{"type":"E","price":20}}];
var result = _(data)
// group by the combined group keys
.groupBy(function(o) {
// extract all group keys and join them to a string
return _.at(o, ['key', 'legs[0].date', 'fare.type']).join('');
})
.map(function(group) {
// get the object object with the minimum fare.price
return _.minBy(group, 'fare.price');
})
.value();
console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>
Related
I have the following array:
arr = [
{ name: 'Apple', store: 'A' },
{ name: 'Banana', store: 'A' },
{ name: 'Carrot', store: 'B' },
{ name: 'Potato', store: 'B' },
{ name: 'Tomato', store: 'A' }
]
I need to sort the array by switching between each store like this:
arr = [
{ name: 'Apple', store: 'A' },
{ name: 'Carrot', store: 'B' },
{ name: 'Banana', store: 'A' },
{ name: 'Tomato', store: 'B' },
{ name: 'Potato', store: 'A' }
]
How can I do that with ruby ?
I came up with something :)
arr = [
{ name: 'Apple', store: 'A' },
{ name: 'Banana', store: 'A' },
{ name: 'Carrot', store: 'B' },
{ name: 'Potato', store: 'B' },
{ name: 'Tomato', store: 'A' }
]
first, *rest = arr.group_by { |h| h[:store] }.values
first.zip(*rest).flatten.compact
See it in action: Replit
I have a nested array that looks like this:
Nested Array
I would like to traverse through the nested array and find the max value of the 'value' field situated in grouped_ratings > values > value
I have tried the following and can't seem to figure out the issue.
var yMax = d3.max(grouped_ratings, function(g) {
return d3.map(g.values, function(v) {
return d3.max(v.value)
})
});
Change d3.map to d3.max and in the inner-most function, you can just return v.value. Here's what it looks like:
d3.max(grouped_ratings, function (g) {
return d3.max(g.values, function (v) {
return v.value;
});
});
Or as a one-liner: d3.max(grouped_ratings, g => d3.max(g.values, v => v.value))
These snippets work when grouped_ratings has the format
grouped_ratings = [
{
key: '2011',
values: [
{ key: '1', value: 151 },
{ key: '2', value: 12 },
{ key: '3', value: 314 },
{ key: '4', value: 178 },
{ key: '5', value: 31 },
{ key: '6', value: 1 },
{ key: '7', value: 1 },
]
},
{
key: '2012',
values: [
{ key: '1', value: 203 },
{ key: '2', value: 4 },
{ key: '3', value: 41 },
{ key: '4', value: 87 },
{ key: '5', value: 13 },
{ key: '6', value: 10 },
{ key: '7', value: 100 },
]
},
]
I've got these streams
const site = of([
{ name: 'Joe', age: 30, tsUpdate: 5 },
{ name: 'Frank', age: 20, tsUpdate: 4 },
{ name: 'Ryan', age: 50, tsUpdate: 4 }
]);
const db = of([
{ name: 'Jonas', age: 30, tsUpdate: 4 },
{ name: 'Frank', age: 21, tsUpdate: 8 },
{ name: 'Calgor', age: 50, tsUpdate: 4 },
{ name: 'Joe', age: 30, tsUpdate: 4 },
]);
The goal is to have a single array with distinct value for
name but with the highest tsUpdate
So for instance
{ name: 'Joe', age: 30, tsUpdate: 5 }
{ name: 'Joe', age: 30, tsUpdate: 4 }
I want
{ name: 'Joe', age: 30, tsUpdate: 5 }
I am able to have distinct value for name property
but I don't know how to pick the highest value for tsUpdate
https://stackblitz.com/edit/rxjs-mhept2?devtoolsheight=60
This could be a way to solve it:
forkJoin(
[
site,
db
]
).pipe (
map(([site, db]) => [...site, ...db]),
// Emit each item individually
mergeAll(),
// Group by their name
groupBy(o => o.name),
// For each separate group, find the object with the highest `tsUpdate`
mergeMap(
grp$ => grp$.pipe(
reduce((acc, crt) => crt.tsUpdate > acc.tsUpdate ? crt : acc),
),
),
// At the end, collect all the objects in an array
toArray(),
).subscribe(console.log);
A groupBy's group is a Subject, and that's why we can use mergeMap afterwards. That subject will emit whenever it finds an object that matches with its key.
StackBlitz.
My chart is plotting x-axis points from Jan 1 1970. My js is below. Is the format of my x-coordinates what is causing the problem, and if so, how can I get these dates right?
var chart = new Chart(document.getElementById('myChart'), {
type: 'line',
data: {
datasets: [{
data: [{x:15-04-2018,y:10},{x:16-04-2018,y:20},{x:17-04-2018,y:30}],
borderColor: '#3e95cd',
fill: false
}]},
options: {
scales: {
xAxes: [{
type: 'time',
unit: 'day' ,
distribution: 'linear',
ticks: { source: 'data' },
time: { displayFormats: { day: 'MMM DD' } }
}]
},
title: {
display: true,
text: 'Student Assessment Cluster Scores'
},
} });
The date values must be entered as a javascript Date object. Just like the documentation says,
data: [{
x: new Date(),
y: 1
}, {
t: new Date(),
y: 10
}]
So in my question, the dates could be represented by:
data: [
{x:new date(15-04-2018),y:10},
{x:new date(16-04-2018),y:20},
{x:new date(17-04-2018),y:30}
]
Taking a look at different examples on the documentation, I found that the only way to include multiple graphs (or lines) on a serial chart would be to do so by placing the data in one array as such:
[{
category: 1,
value1: .8,
value2: .64,
},
{
category: 2,
value1: .75,
value2: -.4,
}];
However, this is rather tedious if you have multiple data sets you are trying to display at once; is there an alternative way to do this, where you would pass multiple arrays at once (this is what I figured an implementation would look like, but it is not the case):
[
// First set of data
{ category: 0, value: .5},
{ category: 1, value: .5},
{ category: 2, value: .5},
{ category: 3, value: .5},
{ category: 4, value: .3},
{ category: 5, value: 1}
],
// Second set of data
[
{ category: 0, value: .5 },
{ category: 1, value: .3 },
{ category: 2, value: .25 },
{ category: 3, value: .6 },
{ category: 4, value: .79 },
{ category: 5, value: .81 }
]],
Any ideas on how this may be done? Or would I need to do switch to a different type of chart?
This isn't possible in the regular AmCharts JavaScript Charts library. The only supported format is a single array of objects with the values consolidated by category as you've noticed. You'll have to preprocess your data beforehand.
The AmCharts Stock Chart library supports separate arrays of data in the dataSets array, however it only supports date-based data.
AmCharts.makeChart("chartdiv", {
"type": "stock",
"dataSets": [{
// other properties omitted
"dataProvider": [{
category: "2017-08-01,
value: 3
}, {
category: "2017-08-02,
value: 2
}, {
category: "2017-08-03,
value: 1
}, // ...
]
}, {
// other properties omitted
"dataProvider": [{
category: "2017-08-01,
value: 10
}, {
category: "2017-08-02,
value: 9
}, {
category: "2017-08-03,
value: 5
}, // ...
]
},
// ...
]
// ...
});
You can see this in action in the any of the stock chart demos.