javascript中定义一维数组，如何从TXT文件中为其赋值？
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通常，在JS中定义一维数据可以这样写：
var name_list = new Array("张三","李四","王二","刘五","小花");
问题：
已经建立了一个TXT文件，格式为"张三","李四","王二","刘五","小花"，或每个人名一行，即如下格式：
张三
李四
王二
刘五
小花
请问：如何上面JS函数new Array括号里的内容，自动提取TXT文件来填充呢？
不胜感激！跪求！
其实只要读取成字符串用 split("\\n") 切割就可以了。
因为你没有说哪个平台，那就拿浏览器举个例子：
<!DOCTYPE html><html>
<body>
<input type="file" id="input">
<script>
(function()
var input = document.querySelector('#input');
input.addEventListener('change', function(e)
handFile(e.target.files[0]);
);
function handFile(file)
var reader = new FileReader();
reader.onload = function(e)
console.log(e.target.result.split("\\n"));
;
reader.readAsText(file);
)();
</script>
</body>
</html>
浏览器需要<input>标签读取文件，node.js 的话可以从命令行参数 process.argv 来传入文本
想要在脚本里面读取文本文件可以用 fs 模块。
比如，在一个test.js文件中写上
var fso = new ActiveXObject("Scripting.FileSystemObject");
var f = fso.OpenTextFile("c:\\\\文件名.txt", ForReading, false); //读文件
var s = f.ReadLine();读一行
如果要在浏览器中读写，需要大大降低自定义安全级别，允许使用本地ActiveX对象。
通常这么做是非常危险的。。
将数组从平面一维转换为树，如 javascript/lodash
【中文标题】将数组从平面一维转换为树，如 javascript/lodash【英文标题】：transform an array from a flat 1 dimensional to a tree like in javascript/lodash 【发布时间】：2020-08-19 00:04:36 【问题描述】：我无法将以下数组 data1 转换为看起来像 data2：我尝试使用 lodash 但它有点奇怪 _gropuby 给了我一个对象数组。我应该在数组内部循环...为此创建一个自定义函数。或者 lodash 中是否有一个技巧来简化这一点。谢谢 /************************************************* *************************************************
let data1 = [
KlasCode: "AA",
LESDatum: "06/02/2017",
LESID: "1",
ModuleID: "1061",
ParticipationLetterCode: "Y"
,
KlasCode: "AA",
LESDatum: "07/02/2017",
LESID: "2",
ModuleID: "1061",
ParticipationLetterCode: "X",
,
KlasCode: "AA",
LESDatum: "13/02/2017",
LESID: "3",
ModuleID: "1062",
ParticipationLetterCode: "Z"
,
KlasCode: "BB",
LESDatum: "16/02/2017",
LESID: "4",
ModuleID: "1063",
ParticipationLetterCode: "X"
]
//The output should be like a tree array system, something more organized such as the following code :
let data2 = [
KlasCode: "AA",
Modules: [
ModuleID: "1061",
Participation: [
ParticipationLetterCode: "Y",
LESDatum: "06/02/2017",
LESID: "1"
,
ParticipationLetterCode: "X",
LESDatum: "07/02/2017",
LESID: "2"
,
ModuleID: "1062",
Participation:[
ParticipationLetterCode: "Z",
LESDatum: "13/02/2017",
LESID: "3"
]
]
,
KlasCode: "BB",
Modules: [
ModuleID: "1063",
Participation: [
ParticipationLetterCode: "x",
LESDatum: "6/02/2017",
LESID: "4"
]
]
]【问题讨论】：
应该是 AA 抱歉，我更新了东西 thx。我试图结合 .map() 和 _gropuby。没有运气 这有帮助吗？ 【参考方案1】：创建了一个函数来做同样的事情，希望这会有所帮助-:
const custommodifier = (data) => Object.values(data.reduce((acc,KlasCode, ModuleID, ...participationData) =>
if(acc[KlasCode])
acc[KlasCode].Modules[0].Participation.push(
...participationData
)
else
acc[KlasCode] =
KlasCode,
Modules: [
ModuleID,
Participation: [
...participationData
]
]
return acc;
, ));
let data = [
KlasCode: "AA",
LESDatum: "06/02/2017",
LESID: "1",
ModuleID: "1061",
ParticipationLetterCode: "Y"
,
KlasCode: "AA",
LESDatum: "07/02/2017",
LESID: "2",
ModuleID: "1061",
ParticipationLetterCode: "X",
,
KlasCode: "AA",
LESDatum: "13/02/2017",
LESID: "3",
ModuleID: "1061",
ParticipationLetterCode: "Z"
,
KlasCode: "BB",
LESDatum: "16/02/2017",
LESID: "4",
ModuleID: "1062",
ParticipationLetterCode: "X"
]
console.log(custommodifier(data))【讨论】：
Abhisar，我一直在尝试将这个 reduce 函数用于类似的线程：你能帮我检查一下吗？：***.com/q/61610032/9248040thx【参考方案2】：您可以采用动态方法，使用一组键广告组名称，然后从实际对象中取出键。最后，构建嵌套组后，将最终对象添加到最后一个组。
如有必要，此方法适用于更多嵌套组。
let data = [ KlasCode: "AA", LESDatum: "06/02/2017", LESID: "1", ModuleID: "1061", ParticipationLetterCode: "Y" , KlasCode: "AA", LESDatum: "07/02/2017", LESID: "2", ModuleID: "1061", ParticipationLetterCode: "X" , KlasCode: "AA", LESDatum: "13/02/2017", LESID: "3", ModuleID: "1061", ParticipationLetterCode: "Z" , KlasCode: "BB", LESDatum: "16/02/2017", LESID: "4", ModuleID: "1062", ParticipationLetterCode: "X" ],
groups = [['KlasCode', 'Modules'], ['ModuleID', 'Participation']],
result = data.reduce((r, o) =>
groups
.reduce((p, [key, group]) =>
let value, temp;
( [key]: value, ...o = o);
temp = p.find(q => q[key] === value);
if (!temp) p.push(temp = [key]: value, [group]: [] );
return temp[group];
, r)
.push(o);
return r;
, []);
console.log(result);.as-console-wrapper max-height: 100% !important; top: 0; 【讨论】：
【参考方案3】：我会使用groupBy 函数和Object.entries。您将需要使用它两次，以处理您的两个级别的分组。
您可以使用来自 lodash 的groupBy（或者来自 Ramda 的那个，或者其他任何地方），或者这里包含的简单的那个。
const groupBy = (fn) => (xs) =>
xs .reduce((a, x) => (... a, [fn(x)]: [... (a [fn (x)] || []), x]), )
const transform = (data) => Object.entries (groupBy (x => x.KlasCode) (data))
.map(([KlasCode, Modules]) => (
KlasCode,
Modules: Object.entries(groupBy (x => x.ModuleID) (Modules))
.map(([ModuleID, Participations]) => (
ModuleID,
Participation: Participations.map ((ParticipationLetterCode, KlasCode, ...rest) => rest)
)
)
))
let data1 = [KlasCode: "AA", LESDatum: "06/02/2017", LESID: "1", ModuleID: "1061", ParticipationLetterCode: "Y", KlasCode: "AA", LESDatum: "07/02/2017", LESID: "2", ModuleID: "1061", ParticipationLetterCode: "X", KlasCode: "AA", LESDatum: "13/02/2017", LESID: "3", ModuleID: "1062", ParticipationLetterCode: "Z", KlasCode: "BB", LESDatum: "16/02/2017", LESID: "4", ModuleID: "1063", ParticipationLetterCode: "X"]
console .log (transform (data1)).as-console-wrapper min-height: 100% !important; top: 0更新——Ramda 替代方案
我对上述解决方案和这里的其他答案并不感到兴奋。有时发生这种情况时，我会在 Ramda 中重写（免责声明：我是它的作者之一），然后将涉及的 Ramda 函数移植到 vanilla JS 中。这次我不打算做后者，但我将分享我如何利用像 Ramda 这样的库来做到这一点。我猜lodash中也有类似的功能。
const groupByProp = (propName, childName) => pipe (
groupBy (prop (propName)),
toPairs,
map (evolve ([ , map (dissoc (propName))])),
map (zipObj ([propName, childName]))
)
const transform = pipe (
groupByProp('KlasCode', 'Modules'),
map (evolve (Modules: groupByProp('ModuleID', 'Participation')))
)
let data1 = [KlasCode: "AA", LESDatum: "06/02/2017", LESID: "1", ModuleID: "1061", ParticipationLetterCode: "Y", KlasCode: "AA", LESDatum: "07/02/2017", LESID: "2", ModuleID: "1061", ParticipationLetterCode: "X", KlasCode: "AA", LESDatum: "13/02/2017", LESID: "3", ModuleID: "1062", ParticipationLetterCode: "Z", KlasCode: "BB", LESDatum: "16/02/2017", LESID: "4", ModuleID: "1063", ParticipationLetterCode: "X"]
console .log (transform (data1)).as-console-wrapper min-height: 100% !important; top: 0<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js"></script>
<script> const groupBy, prop, toPairs, map, evolve, dissoc, zipObj, pipe = R </script>我觉得这些功能似乎更简单，更好地展示了转换的步骤。但这还不足以成为包含库的理由。但是一旦你遇到了一些这样的情况，图书馆似乎就很有意义了。
我并不是要在这里推 Ramda，只是要指出，当您拥有实用程序库的工具时，您通常可以编写更简单的代码。
【讨论】：
感谢 Scott 的建议。 你能帮我解决这个问题吗？：***.com/q/61610032/9248040以上是关于javascript中定义一维数组，如何从TXT文件中为其赋值？的主要内容，如果未能解决你的问题，请参考以下文章