循环遍历地图列表以使用JS过滤地图键值

Question

如何循环遍历地图列表以从下面过滤出使用JS的记录地图的List中的SearchMap键值？

地图

file = open(filename', 'w')

for x in xrange(len(first_column)):
     file.write(text)
file.close

列表

var searchMap = new Map()
searchMap.set("ed_mood", "strong")
searchMap.set("ed_target_audience", "Expert")
searchMap.set("ed_clip_type", "intro")

注意：要过滤掉我使用AlaSql的记录，但它没有给出预期的结果。任何其他JS方式来过滤地图到地图列表？

var master_data =
[
    {ed_mood: "Light", ed_rating: 10, ed_target_audience: "Novice", ed_clip_type: "Basic"},
    {ed_mood: "Light", ed_rating: 5, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 8, ed_target_audience: "Expert", ed_clip_type: "Intro"},
    {ed_mood: "Strong", ed_rating: 7, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 10, ed_target_audience: "Expert", ed_clip_type: "intro"}
]

预期结果

var filter_result = [];
searchMap.forEach(function(value, key){
    var data  = alasql(`select * from ? where ${key} like ?`,[master_data, `%${value}%`]);
    $.each(data, (i) => filter_result.push(data[i]));
});

Answer 1

以下代码filters master_data仅return Objects与param中的每个searchMap匹配。

有关详细信息，请参阅Array.prototype.filter()，Array.prototype.every()，Map.entries()，JSON.stringify()和String.toLowercase()。

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// Search Map.
const searchMap = new Map([
  ['ed_mood', 'strong'],
  ['ed_target_audience', 'Expert'],
  ['ed_clip_type', 'intro']
])

// Master Data.
const master_data = [
  {ed_mood: 'Light', ed_rating: 10, ed_target_audience: 'Novice', ed_clip_type: 'Basic'},
  {ed_mood: 'Light', ed_rating: 5, ed_target_audience: 'Expert', ed_clip_type: 'Q&A'},
  {ed_mood: 'Strong', ed_rating: 8, ed_target_audience: 'Expert', ed_clip_type: 'Intro'},
  {ed_mood: 'Strong', ed_rating: 7, ed_target_audience: 'Expert', ed_clip_type: 'Q&A'},
  {ed_mood: 'Strong', ed_rating: 10, ed_target_audience: 'Expert', ed_clip_type: 'intro'}
]

// Output.
const output = 
  
  // Filter master_data for Objects that include every searchpoint.
  master_data.filter((datapoint) =>
   
  // Destructuring assignment + Map.entries to reveal searchMap entries.
  [...searchMap.entries()].every((searchpoint) =>
  
  // Object.entries() to reveal datapoint entries. 
  // JSON.stringify + toLowerCase() for normalization.
  JSON.stringify(Object.entries(datapoint)).toLowerCase().includes(JSON.stringify(searchpoint).toLowerCase())))


// Log.
console.log(output)

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Answer 2

代码中的问题是您使用（隐式）OR运算符连接条件。您的预期结果表明您应该使用AND运算符。

您可以先构建SQL命令，然后使用AlaSQL执行它（只是一个建议，您向我介绍了AlaSQL :-)）

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var searchMap = new Map();
searchMap.set("ed_mood", "strong");
searchMap.set("ed_target_audience", "Expert");
searchMap.set("ed_clip_type", "intro");

var master_data =
[
    {ed_mood: "Light", ed_rating: 10, ed_target_audience: "Novice", ed_clip_type: "Basic"},
    {ed_mood: "Light", ed_rating: 5, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 8, ed_target_audience: "Expert", ed_clip_type: "Intro"},
    {ed_mood: "Strong", ed_rating: 7, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 10, ed_target_audience: "Expert", ed_clip_type: "intro"}
];

var command = "SELECT * FROM ? WHERE";
var values = [];

searchMap.forEach(function(value, key){
	command += ` ${key} LIKE ? AND`;
	values.push('%' + value);
});

//Removing the last "AND"
command = command.substring(0, command.length -4);

var filter_result = alasql(command, [master_data, ...values]);

console.log(filter_result);

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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/alasql/0.4.5/alasql.min.js"></script>

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没有AlaSQL的解决方案

使用ES6，您的代码可以是：

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var searchMap = new Map();
searchMap.set("ed_mood", "strong");
searchMap.set("ed_target_audience", "Expert");
searchMap.set("ed_clip_type", "intro");

var master_data =
[
    {ed_mood: "Light", ed_rating: 10, ed_target_audience: "Novice", ed_clip_type: "Basic"},
    {ed_mood: "Light", ed_rating: 5, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 8, ed_target_audience: "Expert", ed_clip_type: "Intro"},
    {ed_mood: "Strong", ed_rating: 7, ed_target_audience: "Expert", ed_clip_type: "Q&A"},
    {ed_mood: "Strong", ed_rating: 10, ed_target_audience: "Expert", ed_clip_type: "intro"}
];

var filter_result = master_data.filter(function(x) {
    for (var [key, value] of searchMap) {
        //Change the comparison to fit your needs
    
        // Condition to handle null , undefined and ''(blank) values
        if (x[key] !== null && typeof x[key] !== 'undefined' && x[key] !== '') {
            if (x[key].toLowerCase() !== value.toLowerCase()) return false;
        } else {
            return false;
        }
    }
    return true;
});

console.log(filter_result);

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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/alasql/0.4.5/alasql.min.js"></script>

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Answer 3

您可以在此处使用lodash的filter方法。

在你的情况下，你会这样做：

const result = _filter(master_data, {
  ed_mood: 'strong',
  ed_target_audience: 'expert',
  ed_clip_type: 'intro'
});

在lodash/filter

上详细了解相关信息