Question

我想将二进制字符串转换为数字 E.g

var binary = "1101000" // code for 104
var digit = binary.toString(10); // Convert String or Digit (But it does not work !)
console.log(digit);

怎么可能？感谢

Answer 1

parseInt函数将字符串转换为数字，它接受第二个参数，指定字符串表示形式所在的基数：

var digit = parseInt(binary, 2);

<强> See it in action

Answer 2

ES6支持整数的binary numeric literals，因此如果二进制字符串是不可变的，就像问题中的示例代码一样，可以只使用前缀0b或{{ 1}}：

0B

Answer 3

使用radix的parseInt参数：

var binary = "1101000";
var digit = parseInt(binary, 2);
console.log(digit);

Answer 4

带有基数的

parseInt()是最好的解决方案（正如许多人所说）：

但是如果你想在没有parseInt的情况下实现它，这里有一个实现：

  function bin2dec(num){
    return num.split('').reverse().reduce(function(x, y, i){
      return (y === '1') ? x + Math.pow(2, i) : x;
    }, 0);
  }

Answer 5

        var num = 10;

        alert("Binary " + num.toString(2));   //1010
        alert("Octal " + num.toString(8));    //12
        alert("Hex " + num.toString(16));     //a

        alert("Binary to Decimal "+ parseInt("1010", 2));  //10
        alert("Octal to Decimal " + parseInt("12", 8));    //10
        alert("Hex to Decimal " + parseInt("a", 16));      //10

Answer 6

function binaryToDecimal(string) {
    let decimal = +0;
    let bits = +1;
    for(let i = 0; i < string.length; i++) {
        let currNum = +(string[string.length - i - 1]);
        if(currNum === 1) {
            decimal += bits;
        }
        bits *= 2;
    }
    console.log(decimal);
}

Answer 7

仅用于功能性JS练习的另一个实现可能是

var bin2int = s => Array.prototype.reduce.call(s, (p,c) => p*2 + +c)
console.log(bin2int("101010"));

其中+c强制String输入c到Number类型值以便正确添加。

Answer 8

我收集了所有其他建议，并创建了以下函数，该函数具有3个参数：数字和该数字来自的基数以及该数字将要基于的基数：

changeBase(1101000, 2, 10) => 104

运行代码段以自行尝试：

function changeBase(number, fromBase, toBase) {
                        if (fromBase == 10)
                            return (parseInt(number)).toString(toBase)
                        else if (toBase == 10)
                            return parseInt(number, fromBase);
                        else{
                            var numberInDecimal = parseInt(number, fromBase);
                            return (parseInt(numberInDecimal)).toString(toBase);
                    }
}

$("#btnConvert").click(function(){
  var number = $("#txtNumber").val(),
  fromBase = $("#txtFromBase").val(),
  toBase = $("#txtToBase").val();
  $("#lblResult").text(changeBase(number, fromBase, toBase));
});

#lblResult{
  padding: 20px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="txtNumber" type="text" placeholder="Number" />
<input id="txtFromBase" type="text" placeholder="From Base" />
<input id="txtToBase" type="text" placeholder="To Base" />
<input id="btnConvert" type="button" value="Convert" />
<span id="lblResult"></span>

<p>Hint: <br />
Try 110, 2, 10 and it will return 6; (110)<sub>2</sub> = 6<br />

or 2d, 16, 10 => 45 meaning: (2d)<sub>16</sub> = 45<br />
or 45, 10, 16 => 2d meaning: 45 = (2d)<sub>16</sub><br />
or 2d, 2, 16 => 2d meaning: (101101)<sub>2</sub> = (2d)<sub>16</sub><br />
</p>

仅供参考：如果您想将2d作为十六进制数字传递，则需要将其作为字符串发送，如下所示： changeBase('2d', 16, 10)

Answer 9

使用一些更多的ES6语法和自动功能对常规二进制转换算法进行了轻微修改：

// Step 1: Convert binary sequence string to Array (assuming it wasnt already passed as array)
// Step 2: Reverse sequence to force 0 index to start at right-most binary digit as binary is calculated right-left
// Step 3: 'reduce' Array function traverses array, performing summation of (2^index) per binary digit [only if binary digit === 1] (0 digit always yields 0)
//                                    n
// NOTE: Binary conversion formula -  ∑ (d * 2^i)   {where d=binary digit, i=array index, n=array length-1 (starting from right)} 
//                                   i=0

let decimal = Array.from(binaryString).reverse().reduce((total, val, index)=>val==="1"?total + 2**index:total, 0);  
console.log(`Converted BINARY sequence (${binaryString}) to DECIMAL (${decimal}).`);

如何将二进制字符串转换为十进制？

9 个答案: