如何使用JavaScript从* .CSV文件读取数据？

#1 楼

 heading1,heading2,heading3,heading4,heading5,value1_1,...,value5_2

$(document).ready(function() {
    $.ajax({
        type: "GET",
        url: "data.txt",
        dataType: "text",
        success: function(data) {processData(data);}
     });
});

function processData(allText) {
    var record_num = 5;  // or however many elements there are in each row
    var allTextLines = allText.split(/\r\n|\n/);
    var entries = allTextLines[0].split(',');
    var lines = [];

    var headings = entries.splice(0,record_num);
    while (entries.length>0) {
        var tarr = [];
        for (var j=0; j<record_num; j++) {
            tarr.push(headings[j]+":"+entries.shift());
        }
        lines.push(tarr);
    }
    // alert(lines);
}

heading1,heading2,heading3,heading4,heading5
value1_1,value2_1,value3_1,value4_1,value5_1
value1_2,value2_2,value3_2,value4_2,value5_2

$(document).ready(function() {
    $.ajax({
        type: "GET",
        url: "data.txt",
        dataType: "text",
        success: function(data) {processData(data);}
     });
});

function processData(allText) {
    var allTextLines = allText.split(/\r\n|\n/);
    var headers = allTextLines[0].split(',');
    var lines = [];

    for (var i=1; i<allTextLines.length; i++) {
        var data = allTextLines[i].split(',');
        if (data.length == headers.length) {

            var tarr = [];
            for (var j=0; j<headers.length; j++) {
                tarr.push(headers[j]+":"+data[j]);
            }
            lines.push(tarr);
        }
    }
    // alert(lines);
}

#2 楼

heading1,heading2,heading3,heading4,heading5
value1_1,value2_1,value3_1,value4_1,value5_1
value1_2,value2_2,value3_2,value4_2,value5_2

var data = $.csv.toObjects(csv):

[
  { heading1:"value1_1",heading2:"value2_1",heading3:"value3_1",heading4:"value4_1",heading5:"value5_1" } 
  { heading1:"value1_2",heading2:"value2_2",heading3:"value3_2",heading4:"value4_2",heading5:"value5_2" }
]

#3 楼

var data = Papa.parse(csvString);

Papa.parse(file, {
    complete: function(results) {
        console.log(results);
    }
});

Papa.parse("http://example.com/bigfoo.csv", {
    download: true,
    step: function(row) {
        console.log("Row:", row.data);
    },
    complete: function() {
        console.log("All done!");
    }
});

#4 楼

import { csv } from 'd3-request';
import url from 'path/to/data.csv';

csv(url, function(err, data) {
 console.log(data);
})

#5 楼

// Parse a CSV row, accounting for commas inside quotes                   
function parse(row){
  var insideQuote = false,                                             
      entries = [],                                                    
      entry = [];
  row.split('').forEach(function (character) {                         
    if(character === '"') {
      insideQuote = !insideQuote;                                      
    } else {
      if(character == "," && !insideQuote) {                           
        entries.push(entry.join(''));                                  
        entry = [];                                                    
      } else {
        entry.push(character);                                         
      }                                                                
    }                                                                  
  });
  entries.push(entry.join(''));                                        
  return entries;                                                      
}

"foo, the column",bar
2,3
"4, the value",5

// csv could contain the content read from a csv file
var csv = '"foo, the column",bar\n2,3\n"4, the value",5',

    // Split the input into lines
    lines = csv.split('\n'),

    // Extract column names from the first line
    columnNamesLine = lines[0],
    columnNames = parse(columnNamesLine),

    // Extract data from subsequent lines
    dataLines = lines.slice(1),
    data = dataLines.map(parse);

// Prints ["foo, the column","bar"]
console.log(JSON.stringify(columnNames));

// Prints [["2","3"],["4, the value","5"]]
console.log(JSON.stringify(data));

#6 楼

Papa.parse(e, {
            header:true,
            before: function(file, inputElem){ console.log('Attempting to Parse...')},
            error: function(err, file, inputElem, reason){ console.log(err); },
            complete: function(results, file){ $.PAYLOAD = results; }
        });

#7 楼

Time,data1,data2,data2
08/11/2015 07:30:16,602,0.009,321

$(document).ready(function() {
 // AJAX in the data file
    $.ajax({
        type: "GET",
        url: "data.csv",
        dataType: "text",
        success: function(data) {processData(data);}
        });

    // Let's process the data from the data file
    function processData(data) {
        var lines = data.split(/\r\n|\n/);

        //Set up the data arrays
        var time = [];
        var data1 = [];
        var data2 = [];
        var data3 = [];

        var headings = lines[0].split(','); // Splice up the first row to get the headings

        for (var j=1; j<lines.length; j++) {
        var values = lines[j].split(','); // Split up the comma seperated values
           // We read the key,1st, 2nd and 3rd rows 
           time.push(values[0]); // Read in as string
           // Recommended to read in as float, since we'll be doing some operations on this later.
           data1.push(parseFloat(values[1])); 
           data2.push(parseFloat(values[2]));
           data3.push(parseFloat(values[3]));

        }

    // For display
    var x= 0;
    console.log(headings[0]+" : "+time[x]+headings[1]+" : "+data1[x]+headings[2]+" : "+data2[x]+headings[4]+" : "+data2[x]);
    }
})

#8 楼

function CSVParse(csvFile)
{
    this.rows = [];

    var fieldRegEx = new RegExp('(?:\s*"((?:""|[^"])*)"\s*|\s*((?:""|[^",\r\n])*(?:""|[^"\s,\r\n]))?\s*)(,|[\r\n]+|$)', "g");   
    var row = [];
    var currMatch = null;

    while (currMatch = fieldRegEx.exec(this.csvFile))
    {
        row.push([currMatch[1], currMatch[2]].join('')); // concatenate with potential nulls

        if (currMatch[3] != ',')
        {
            this.rows.push(row);
            row = [];
        }

        if (currMatch[3].length == 0)
            break;
    }
}

#9 楼

for (var i=1; i<allTextLines.length; i++) {

for (var i=0; i<allTextLines.length; i++) {

#10 楼

 function readSingleFile(e) {
  var file = e.target.files[0];
  if (!file) {
    return;
  }

  var reader = new FileReader();
  reader.onload = function(e) {
    var contents = e.target.result;
    displayContents(contents);
    displayParsed(contents);
  };
  reader.readAsText(file);
}

function displayContents(contents) {
  var element = document.getElementById('file-content');
  element.textContent = contents;
}

function displayParsed(contents) {
  const element = document.getElementById('file-parsed');
  const json = contents.split(',');
  element.textContent = JSON.stringify(json);
}

document.getElementById('file-input').addEventListener('change', readSingleFile, false); 

 <input type="file" id="file-input" />

<h3>Raw contents of the file:</h3>
<pre id="file-content">No data yet.</pre>

<h3>Parsed file contents:</h3>
<pre id="file-parsed">No data yet.</pre> 

#11 楼

"Harry\nPotter","21","Gryffindor"

Harry
Potter,21,Gryffindor

 const csv = require('csvtojson');
if (files && files.length > 0) {
    const file: File = files.item(0);
    const reader: FileReader = new FileReader();
    reader.readAsText(file);
    reader.onload = (e) => {
    const csvs: string = reader.result as string;
    csv({
        output: "json",
        noheader: false
    }).fromString(csvs)
        .preFileLine((fileLine, idx) => {
        //Convert csv header row to lowercase before parse csv file to json
        if (idx === 0) { return fileLine.toLowerCase() }
        return fileLine;
        })
        .then((result) => {
        // list of json in result
        });
    }
}
  

#12 楼

$(function() {

      $("#upload").bind("click", function() {
            var regex = /^([a-zA-Z0-9\s_\.\-:])+(.csv|.xlsx)$/;
            if (regex.test($("#fileUpload").val().toLowerCase())) {
              if (typeof(FileReader) != "undefined") {
                var reader = new FileReader();
                reader.onload = function(e) {
                    var customers = new Array();
                    var rows = e.target.result.split("\r\n");
                    for (var i = 0; i < rows.length - 1; i++) {
                      var cells = rows[i].split(",");
                      if (cells[0] == "" || cells[0] == undefined) {
                        var s = customers[customers.length - 1];
                        s.Ord.push(cells[2]);
                      } else {
                        var dt = customers.find(x => x.Number === cells[0]);
                        if (dt == undefined) {
                          if (cells.length > 1) {
                            var customer = {};
                            customer.Number = cells[0];
                            customer.Name = cells[1];
                            customer.Ord = new Array();

                            customer.Ord.push(cells[2]);
                            customer.Point_ID = cells[3];
                            customer.Point_Name = cells[4];
                            customer.Point_Type = cells[5];
                            customer.Set_ORD = cells[6];
                            customers.push(customer);
                          }
                        } else {
                          var dtt = dt;
                          dtt.Ord.push(cells[2]);

                        }
                      }
                    }

#13 楼

npm i -D any-text

 var reader = require('any-text');
 
reader.getText(`path-to-file`).then(function (data) {
  console.log(data);
});
 

 var reader = require('any-text');
 
const chai = require('chai');
const expect = chai.expect;
 
describe('file reader checks', () => {
  it('check csv file content', async () => {
    expect(
      await reader.getText(`${process.cwd()}/test/files/dummy.csv`)
    ).to.contains('Lorem ipsum');
  });
});