CODEWITHSUNDEEP
javascripthtmlarraystext-files
user3479343
user3479343

Reputation: 29

Separate data from text file using Javascript

I'm working on creating an analytics page that uses data stored in a text file. The text file is used for my highcharts graph and is separated like so:

November 7th 6AM,19.8
November 7th 6PM,19.8
November 8th 6AM,20.4
November 8th 6PM,14.6
November 9th 6AM,15.9
November 9th 6PM,15.1
November 10th 6AM,16.4
November 10th 6PM,16.4

I'm looking to separate that data into 12 calendar panes that will display overall discrepancies for each month. For example, if a date had the value 16, and then it dropped to 10 the next reading, to take a cumulative sum for how many times that happened for the month.

How do I make sure that it reads from the text file in proper order and that it checks to see if the next value went below 10 and tallies that somewhere?

Upvotes: 1

Views: 1630

Answers (2)

Timo Virkkunen
Timo Virkkunen

Reputation: 106

You need to

  1. Fetch the data file
    • One usually does this with AJAX (XMLHttpRequest)
  2. Separate your datapoints
    • Your data seems to be neat enough that you can, for every line in the file, get the name of the month with line.split(" ")[0] and the value with line.split(",")[1]. Splitting a text to lines can usually be as easy as text.split("\n").
  3. Iterate over results
    • For every month-value pair you now have, compare the name of the months. If it is a match and the value has changed by x, increment a value in your books, e.g. discrepancies[monthName]++. Save the name-value pair and continue.

Example: 

// Get the data
var req = new XMLHttpRequest();
req.onreadystatechange = function() {
  if (req.readyState == 4 && req.status == 200) { // If the request is complete with status code "OK"
    handleImportantData(req.responseText);
  }
};
// Define the request to be using the method GET to an URL asynchronously.
req.open("GET", "important_data.txt", true);
req.send();

function handleImportantData(data) {
  var treshold = 5.0;
  var months = {};
  var discrepancies = {};

  // Separate data points.
  var lines = data.split("\n");
  lines.forEach(function(line) {
    // The || 0.0 part sets the value to zero if our data is malformed.
    // We parse the value as a float to prevent it being saved as a string,
    // which would make arithmetic operations on it not work as expected.
    months[line.split(" ")[0]] = parseFloat(line.split(",")[1]) || 0.0;
  });

  // Find discrepancies.
  var previous = {
    name: "",
    value: 0.0
  };
  for (var name in months) {
    // If not already there, initialize the data point with ternary operation including NOP.
    discrepancies[name] ? {} : discrepancies[name] = 0.0;

    // If we're still talking about the same month as before and the value
    // has changed for more than our treshold, save it as a discrepancy.
    if name === previous.name && Math.abs(previous.value - months[name]) > treshold {
      discrepancies[name] ++;
    }

    previous = {
      name: name,
      value: months[name]
    }; // Set this as the previous value.
  }

  // Here we have ready discrepancy data stored in the variable discrepancies.
}

Upvotes: 0

Amir
Amir

Reputation: 1683

Yo can use jQuery to separate the file data into array.

$(document).ready(function() {
    //fetch text file
    $.get('text.txt', function(data) {
        //split on new lines
        var lines = data.split('\n');
        for(var i=0;i<lines.length;i++) {
            // use lines[i] the way you want
        }
    });
});

Then you can use this to get sub-strings:

var a = s.indexOf(',');
var b = s.substring(a,4);

This way you can separate the data and use it as desired.

Upvotes: 1

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