javascript 使用 underscore.js 过滤多维数组
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Filtering through a multidimensional array using underscore.js
提问by McGarnagle
I have an array of eventobjects called events. Each eventhas markets, an array containing marketobjects. Inside here there is another array called outcomes, containing outcomeobjects.
我有一个event名为events. 每个event都有markets，一个包含market对象的数组。里面还有另一个数组叫做outcomes，包含outcome对象。
I want to use Underscore.js or some other method to find all of the events which have markets which have outcomes which have a property named test.
我想使用 Underscore.js 或其他一些方法来查找所有具有名为test.
I imagine this would be achieved using a series of filters but I didn't have much luck!
我想这可以使用一系列过滤器来实现，但我运气不佳！
回答by McGarnagle
I think you can do this using the Underscore.js filterand some(aka "any") methods:
我认为你可以使用 Underscore.jsfilter和some（又名“任何”）方法来做到这一点：
// filter where condition is true
_.filter(events, function(evt) {
// return true where condition is true for any market
return _.any(evt.markets, function(mkt) {
// return true where any outcome has a "test" property defined
return _.any(mkt.outcomes, function(outc) {
return outc.test !== undefined ;
});
});
});
回答by Bergi
No need for Underscore, you could do this with native JS.
不需要 Underscore，你可以用原生 JS 做到这一点。
var events = [{markets:[{outcomes:[{test:x},...]},...]},...];
return events.filter(function(event) {
return event.markets.some(function(market) {
return market.outcomes.some(function(outcome) {
return "test" in outcome;
});
});
});
Yet of course you could also use the corresponding underscore methods (filter/selectand any/some).
当然，您也可以使用相应的下划线方法（filter/select和any/some）。
回答by webjay
var events = [
{
id: 'a',
markets: [{
outcomes: [{
test: 'yo'
}]
}]
},
{
id: 'b',
markets: [{
outcomes: [{
untest: 'yo'
}]
}]
},
{
id: 'c',
markets: [{
outcomes: [{
notest: 'yo'
}]
}]
},
{
id: 'd',
markets: [{
outcomes: [{
test: 'yo'
}]
}]
}
];
var matches = events.filter(function (event) {
return event.markets.filter(function (market) {
return market.outcomes.filter(function (outcome) {
return outcome.hasOwnProperty('test');
}).length;
}).length;
});
matches.forEach(function (match) {
document.writeln(match.id);
});Here's how I would do it, without depending on a library:
这是我将如何做到这一点，而不依赖于图书馆：
var matches = events.filter(function (event) {
return event.markets.filter(function (market) {
return market.outcomes.filter(function (outcome) {
return outcome.hasOwnProperty('test');
}).length;
}).length;
});
