Javascript:将字符串拆分为匹配参数的数组

Question

我有一个包含数字和数学运算符的字符串 (+,x,-, /)混在其中

'12+345x6/789'

我需要将它转换为由这些数学运算符分隔的数组。

[12, +, 345, x, 6,/, 789]

执行此操作的简单方法是什么？

Answer 1

连续 split non-digit chars \D+ 你得到

console.log ('12+345x6/789'.split (/\D+/))
// [ '12', '345', '6', '789' ]

如果你添加一个capture group , (\D+) 你也得到了分隔符

console.log ('12+345x6/789'.split (/(\D+)/))
// [ "12", "+", "345", "x", "6", "/", "789" ]

如果你想支持解析小数，将正则表达式更改为 /([^0-9.]+)/ - 注意，上面使用的 \D 是等效的到 [^0-9]，所以我们在这里所做的就是将 . 添加到字符类

console.log ('12+3.4x5'.split (/([^0-9.]+)/))
// [ "12", "+", "3.4", "x", "5" ]

以及编写程序其余部分的可能方法

const cont = x =>
  k => k (x)

const infix = f => x =>
  cont (f (x))

const apply = x => f =>
  cont (f (x))

const identity = x =>
  x

const empty =
  Symbol ()
  
const evaluate = ([ token = empty, ...rest], then = cont (identity)) => {
  if (token === empty) {
    return then
  }
  else {
    switch (token) {
      case "+":
        return evaluate (rest, then (infix (x => y => x + y)))
      case "x":
        return evaluate (rest, then (infix (x => y => x * y)))
      case "/":
        return evaluate (rest, then (infix (x => y => x / y >> 0)))
      default:
        return evaluate (rest, then (apply (Number (token))))
    }
  }
}

const parse = program =>
  program.split (/(\D+)/)
  
const exec = program =>
  evaluate (parse (program)) (console.log)

exec ('')             // 0
exec ('1')            // 1
exec ('1+2')          // 3
exec ('1+2+3')        // 6
exec ('1+2+3x4')      // 24
exec ('1+2+3x4/2')    // 12
exec ('12+345x6/789') // 2