Convert Array presented as String

Question

I have a text-file with following data:

[2, 3, 4]
[1, 3, 2]

When i read the file with fs.read i got Strings like this:

'[2,3,4]'
'[1,3,4]'

And because of that the length of my matrix mat is wrong.

Code:

var mat = [];

var fs = require('fs');
fs.readFile('./data/outfilename', function(err, data) {

  if (err) throw err;
  var array = data.toString().split(/\r?\n/);



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

    if (array[i].length > 0) {
      mat.push(array[i]);
    }
  }

  console.log(mat.length);
  console.log(mat[0].length);



});

How i convert the read-line to an array with numbers?

score 2 · Answer 1 · answered Jul 31 '17 at 22:09

2

You can use JSON.parse to convert the strings in the array to array of numbers:

var array = ['[2,3,4]', '[1,3,4]'];

mat =  array.map(s => JSON.parse(s));

console.log(mat);

answered Jul 31 '17 at 22:09

Psidom

209,562
33
339
356

score 1 · Accepted Answer · answered Jul 31 '17 at 22:08

You can parse the string as JSON:

// dummy data
var array = ['[2,3,4]', '[18,4,3]'];

var mat = [];
for (var i = 0; i < array.length; i++) {
  mat.push(JSON.parse(array[i]));
}

console.log(mat);

Or using map:

// dummy data
var array = ['[2,3,4]', '[18,4,3]'];

var mat = array.map(JSON.parse);

console.log(mat);

score 1 · Answer 3 · answered Jul 31 '17 at 22:10

1

var matrix = array.map(JSON.parse)

will transform your array into the matrix that you want.

The strings at each line are JSON representations of array of numbers, so when you apply JSON.parse on each line you have the corresponding array.

answered Jul 31 '17 at 22:10

Serge Kireev

176
1
8

Convert Array presented as String

3 Answers3