如果我有一个JavaScript对象,如:
var list = {
"you": 100,
"me": 75,
"foo": 116,
"bar": 15
};
是否有一种方法可以根据值对属性进行排序?最后得到
list = {
"bar": 15,
"me": 75,
"you": 100,
"foo": 116
};
如果我有一个JavaScript对象,如:
var list = {
"you": 100,
"me": 75,
"foo": 116,
"bar": 15
};
是否有一种方法可以根据值对属性进行排序?最后得到
list = {
"bar": 15,
"me": 75,
"you": 100,
"foo": 116
};
当前回答
打印稿
下面的函数根据值或值的属性对对象进行排序。如果你不使用TypeScript,你可以删除类型信息,将其转换为JavaScript。
/**
* Represents an associative array of a same type.
*/
interface Dictionary<T> {
[key: string]: T;
}
/**
* Sorts an object (dictionary) by value or property of value and returns
* the sorted result as a Map object to preserve the sort order.
*/
function sort<TValue>(
obj: Dictionary<TValue>,
valSelector: (val: TValue) => number | string,
) {
const sortedEntries = Object.entries(obj)
.sort((a, b) =>
valSelector(a[1]) > valSelector(b[1]) ? 1 :
valSelector(a[1]) < valSelector(b[1]) ? -1 : 0);
return new Map(sortedEntries);
}
使用
var list = {
"one": { height: 100, weight: 15 },
"two": { height: 75, weight: 12 },
"three": { height: 116, weight: 9 },
"four": { height: 15, weight: 10 },
};
var sortedMap = sort(list, val => val.height);
JavaScript对象中键的顺序是不保证的,所以我将排序并将结果返回为一个保留排序顺序的Map对象。
如果你想把它转换回Object,你可以这样做:
var sortedObj = {} as any;
sortedMap.forEach((v,k) => { sortedObj[k] = v });
其他回答
以防万一,有人正在寻找保持对象(键和值),使用@Markus R和@James Moran注释的代码引用,只需使用:
var list = {"you": 100, "me": 75, "foo": 116, "bar": 15};
var newO = {};
Object.keys(list).sort(function(a,b){return list[a]-list[b]})
.map(key => newO[key] = list[key]);
console.log(newO); // {bar: 15, me: 75, you: 100, foo: 116}
为了完整起见,这个函数返回对象属性的排序数组:
function sortObject(obj) {
var arr = [];
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
arr.push({
'key': prop,
'value': obj[prop]
});
}
}
arr.sort(function(a, b) { return a.value - b.value; });
//arr.sort(function(a, b) { return a.value.toLowerCase().localeCompare(b.value.toLowerCase()); }); //use this to sort as strings
return arr; // returns array
}
var list = {"you": 100, "me": 75, "foo": 116, "bar": 15};
var arr = sortObject(list);
console.log(arr); // [{key:"bar", value:15}, {key:"me", value:75}, {key:"you", value:100}, {key:"foo", value:116}]
JSFiddle上面的代码在这里。此解决方案基于本文。
更新的小提琴排序字符串是在这里。您可以从它中删除额外的. tolowercase()转换,以便区分大小写的字符串比较。
这可能是一种将其作为真实有序对象处理的简单方法。不知道它有多慢。也可能更好的while循环。
Object.sortByKeys = function(myObj){
var keys = Object.keys(myObj)
keys.sort()
var sortedObject = Object()
for(i in keys){
key = keys[i]
sortedObject[key]=myObj[key]
}
return sortedObject
}
然后我找到了这个逆函数 http://nelsonwells.net/2011/10/swap-object-key-and-values-in-javascript/
Object.invert = function (obj) {
var new_obj = {};
for (var prop in obj) {
if(obj.hasOwnProperty(prop)) {
new_obj[obj[prop]] = prop;
}
}
return new_obj;
};
So
var list = {"you": 100, "me": 75, "foo": 116, "bar": 15};
var invertedList = Object.invert(list)
var invertedOrderedList = Object.sortByKeys(invertedList)
var orderedList = Object.invert(invertedOrderedList)
var list = {
"you": 100,
"me": 75,
"foo": 116,
"bar": 15
};
function sortAssocObject(list) {
var sortable = [];
for (var key in list) {
sortable.push([key, list[key]]);
}
// [["you",100],["me",75],["foo",116],["bar",15]]
sortable.sort(function(a, b) {
return (a[1] < b[1] ? -1 : (a[1] > b[1] ? 1 : 0));
});
// [["bar",15],["me",75],["you",100],["foo",116]]
var orderedList = {};
for (var idx in sortable) {
orderedList[sortable[idx][0]] = sortable[idx][1];
}
return orderedList;
}
sortAssocObject(list);
// {bar: 15, me: 75, you: 100, foo: 116}
var list = {
"you": 100,
"me": 75,
"foo": 116,
"bar": 15
};
var tmpList = {};
while (Object.keys(list).length) {
var key = Object.keys(list).reduce((a, b) => list[a] > list[b] ? a : b);
tmpList[key] = list[key];
delete list[key];
}
list = tmpList;
console.log(list); // { foo: 116, you: 100, me: 75, bar: 15 }