How to convert an array of binary numbers that have only 1 and 0 to a corresponding number? Like
var binArray = [1, 0, 1, 1] ;
output = 11;
I know I need to use bitwise operators >> << somehow, but I don't how.
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2 Answers
You can use parseInt() alongwith base or radix argument like this:
> var binArray = [1, 0, 1, 1]
> binArray.join('')
"1011"
> parseInt(binArray.join(''), 2)
11
> parseInt("101", 2)
5
Comments
You could use Array#reduce and a left shift operator <<.
return
r a dec bin
------ ------ ------ ------
1 0 2 10
2 1 5 101
5 1 11 1011
var binArray = [1, 0, 1, 1],
output = binArray.reduce(function (r, a) {
return (r << 1) | a;
});
console.log(output);ES6
var binArray = [1, 0, 1, 1],
output = binArray.reduce((r, a) => (r << 1) | a);
console.log(output);3 Comments
Felix Kling
FWIW, you don't have to pass
0 as initial value, you can just omit it.
Bokchee 88
Thanks for this, could you explain me what means (r << 1) | a?
Nina Scholz
it shifts the value of
r one bit left, that means, the value is like multiplied with two and then a bitwise or is performed with a.