如何在JavaScript中将数字的二进制表示从字符串转换为整数?

2022-01-12 00:00:00 type-conversion javascript

有人可以给我一点建议吗?

Can anybody give me a little advice please?

我有一个字符串，例如01001011"，我需要做的是反转它，所以我使用 .split('') 而不是 .reverse() 现在我需要将数组作为字符串读取并将其转换为整数.有可能吗?

I have a string, for example "01001011" and what I need to do is to reverse it, so I used .split('') than .reverse() and now I need to read the array as a string and convert it to integer. Is it possible?

谢谢

推荐答案

如果要将数组转换回字符串，请使用 join() (MDN) 并将字符串转换为整数使用 parseInt() (MDN).后者的第二个参数是可选的基数.

If you want to convert the array back to a string use join() (MDN) and for converting a string to an integer use parseInt() (MDN). The second argument of the later is an optional radix.

JavaScript 会尝试确定要使用的基数，但要确保始终手动添加基数.引用自 MDN:

JavaScript will try to determine, what radix to use, but to be sure you should always add your radix manually. Citing from MDN:

如果 radix 未定义或为 0，JavaScript 假定如下:

If radix is undefined or 0, JavaScript assumes the following:

  • 如果输入字符串以0x"或0X"开头，则基数为16(十六进制).

  • If the input string begins with "0x" or "0X", radix is 16 (hexadecimal).

如果输入字符串以0"开头，则基数为八(八进制).这个特性是非标准的，一些实现故意不支持它(而是使用基数 10).因此，在使用 parseInt 时始终指定一个基数.

If the input string begins with "0", radix is eight (octal). This feature is non-standard, and some implementations deliberately do not support it (instead using the radix 10). For this reason always specify a radix when using parseInt.

如果输入字符串以任何其他值开头，则基数为 10(十进制).

If the input string begins with any other value, the radix is 10 (decimal).

所以在你的情况下，下面的代码应该可以工作:

So in your case the following code should work:

var a = '01001011';

var b = parseInt( a.split('').reverse().join(''), 2 );

或者只是(如果你想转换起始字符串，不反转):

or just (if you would want to convert the starting string, without the reversal):

var b = parseInt( a, 2 );

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