从对象数组中计算特定键值 [英] Count particular key value from array of object
本文介绍了从对象数组中计算特定键值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有以下 JSON 数组,我想创建对象表单状态键计数
<预><代码>[{"id": "65:0",状态":橙色"},{"id": "65:0",状态":绿色"},{"id": "65:0",状态":橙色"},{"id": "65:0",状态":黄色"},{"id": "65:0",状态":红色"},{"id": "65:0",状态":绿色"},{"id": "65:0",状态":绿色"},{"id": "65:0",状态":橙色"},{"id": "65:0",状态":黄色"},{"id": "65:0",状态":绿色"}]想要统计状态键值并创建如下对象
<代码>{'橙色' : 3,'绿色' : 4,'黄色' : 2,'红色' : 1,}
解决方案
使用 Array#reduce
方法
var res = data.reduce(function(obj, v) {//增加或设置属性//`(obj[v.status] || 0)` 如果定义了则返回属性值//或 0(因为 `undefined` 是一个假值obj[v.status] = (obj[v.status] || 0) + 1;//返回更新后的对象返回对象;//将初始值设置为对象}, {})
var data = [{"id": "65:0",状态":橙色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":橙色"}, {"id": "65:0",状态":黄色"}, {"id": "65:0",状态":红色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":橙色"}, {"id": "65:0",状态":黄色"}, {"id": "65:0",状态":绿色"}];var res = data.reduce(function(obj, v) {obj[v.status] = (obj[v.status] || 0) + 1;返回对象;}, {})console.log(res);
虽然你可以使用 Array#forEach
方法相同的代码.
var res = {};data.forEach(function(v) {res[v.status] = (res[v.status] || 0) + 1;})
var data = [{"id": "65:0",状态":橙色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":橙色"}, {"id": "65:0",状态":黄色"}, {"id": "65:0",状态":红色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":绿色"}, {"id": "65:0",状态":橙色"}, {"id": "65:0",状态":黄色"}, {"id": "65:0",状态":绿色"}];var res = {};data.forEach(function(v) {res[v.status] = (res[v.status] || 0) + 1;})console.log(res);
I have following JSON array I want to create object form status key count
[
{
"id": "65:0",
"status": "ORANGE"
},
{
"id": "65:0",
"status": "GREEN"
},
{
"id": "65:0",
"status": "ORANGE"
},
{
"id": "65:0",
"status": "YELLOW"
},
{
"id": "65:0",
"status": "RED"
},
{
"id": "65:0",
"status": "GREEN"
},
{
"id": "65:0",
"status": "GREEN"
},
{
"id": "65:0",
"status": "ORANGE"
},
{
"id": "65:0",
"status": "YELLOW"
},
{
"id": "65:0",
"status": "GREEN"
}
]
Want to count status key value and create the following Object
{
'ORANGE' : 3,
'GREEN' : 4,
'YELLOW' : 2,
'RED' : 1,
}
解决方案
Use Array#reduce
method
var res = data.reduce(function(obj, v) {
// increment or set the property
// `(obj[v.status] || 0)` returns the property value if defined
// or 0 ( since `undefined` is a falsy value
obj[v.status] = (obj[v.status] || 0) + 1;
// return the updated object
return obj;
// set the initial value as an object
}, {})
var data = [{
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "YELLOW"
}, {
"id": "65:0",
"status": "RED"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "YELLOW"
}, {
"id": "65:0",
"status": "GREEN"
}];
var res = data.reduce(function(obj, v) {
obj[v.status] = (obj[v.status] || 0) + 1;
return obj;
}, {})
console.log(res);
Although you can use Array#forEach
method with the same code.
var res = {};
data.forEach(function(v) {
res[v.status] = (res[v.status] || 0) + 1;
})
var data = [{
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "YELLOW"
}, {
"id": "65:0",
"status": "RED"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "GREEN"
}, {
"id": "65:0",
"status": "ORANGE"
}, {
"id": "65:0",
"status": "YELLOW"
}, {
"id": "65:0",
"status": "GREEN"
}];
var res = {};
data.forEach(function(v) {
res[v.status] = (res[v.status] || 0) + 1;
})
console.log(res);
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