JavaScript: Can we convert 7-segment numbers made of characters(_ & |) into parsed number using javascript/angularjs

Question

JavaScript: Can we convert 7-segment numbers made of characters(_ & |) into parsed number using javascript/angularjs

Input :

 
      _  _     _  _  _  _  _  
    | _| _||_||_ |_   ||_||_| 
    ||_  _|  | _||_|  ||_| _|

Output :

123456789

Answer 1

You could use the encoding of a seven-segment display and the following

• split by linefeed '\n'
• build an array with single ASCII digits
• join a single ASCII digit to a string
• map the ASCII value
• join the result to a string

The ASCII value is taken with an object for a number, and the single segments are weighted with a value for the segment.

Value of segments is 2ⁿ.

  _0_    
|5   1|
  _6_  
|4   2|
  _3_

Dots as segments

 0
561
432

This generates the string

'909561432'
  ^ ^^^^^^  denoted segments with the number above
 ^ ^        no segments

---

For example, take

 012
0
1  |
2  |

the ASCII string of 1, and the above segment numbers, then you get for the segment 1 the value 2¹ and for 2 the value 2². The result is 2 + 4 = 6.

After a lookup in the bits object,

{
    63: 0,
    6: 1, // <----
    91: 2, 
    /* ... */
}

you get the digit 1.

function get7segment(ascii) {
    return ascii.
        split('\n').
        reduce(function (r, a, i) {
            a.match(/.../g).forEach(function (b, j) {
                r[j] = r[j] || [];
                r[j][i] = b;
            });
            return r;
        }, []).
        map(function (a) {
            return a.join('');
        }).
        map(function (a) {
            var bits = { 63: 0, 6: 1, 91: 2, 79: 3, 102: 4, 109: 5, 125: 6, 7: 7, 127: 8, 111: 9, 0: ' ' },
                v = '909561432'.split('').reduce(function (r, v, i) {
                    return r + ((a[i] !== ' ') << v);
                }, 0);
            return v in bits ? bits[v] : '*'; // * is an illegal character
        }).
        join('');
}

function print(ascii) {
    var pre = document.createElement('pre');
    pre.innerHTML = ascii + '\n\n' + get7segment(ascii);
    document.body.appendChild(pre);
}

print(' _     _  _     _  _  _  _  _ \n| |  | _| _||_||_ |_   ||_||_| \n|_|  ||_  _|  | _||_|  ||_| _|');
print('    _  _  _    ...\n  | _| _|  |   ...\n  | _| _|  |   ...');
print('    _  _  _  _  _ \n|_||_|| ||_||_   |\n  | _||_||_||_|  |');