convert string into array of integers

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刺人心
刺人心 2020-11-30 19:32

I want to convert the following string \'14 2\' into an array of two integers. How can I do it ?

11条回答
  •  心在旅途
    2020-11-30 20:07

    The point against parseInt-approach:

    There's no need to use lambdas and/or give radix parameter to parseInt, just use parseFloat or Number instead.


    Reasons:

    1. It's working:

      var src = "1,2,5,4,3";
      var ids = src.split(',').map(parseFloat); // [1, 2, 5, 4, 3]
      
      var obj = {1: ..., 3: ..., 4: ..., 7: ...};
      var keys= Object.keys(obj); // ["1", "3", "4", "7"]
      var ids = keys.map(parseFloat); // [1, 3, 4, 7]
      
      var arr = ["1", 5, "7", 11];
      var ints= arr.map(parseFloat); // [1, 5, 7, 11]
      ints[1] === "5" // false
      ints[1] === 5   // true
      ints[2] === "7" // false
      ints[2] === 7   // true
      
    2. It's shorter.

    3. It's a tiny bit quickier and takes advantage of cache, when parseInt-approach - doesn't:

        // execution time measure function
        // keep it simple, yeah?
      > var f = (function (arr, c, n, m) {
            var i,t,m,s=n();
            for(i=0;i++ f(Number) // first launch, just warming-up cache
      > 3971 // nice =)
      
      > f(Number)
      > 3964 // still the same
      
      > f(function(e){return+e})
      > 5132 // yup, just little bit slower
      
      > f(function(e){return+e})
      > 5112 // second run... and ok.
      
      > f(parseFloat)
      > 3727 // little bit quicker than .map(Number)
      
      > f(parseFloat)
      > 3737 // all ok
      
      > f(function(e){return parseInt(e,10)})
      > 21852 // awww, how adorable...
      
      > f(function(e){return parseInt(e)})
      > 22928 // maybe, without '10'?.. nope.
      
      > f(function(e){return parseInt(e)})
      > 22769 // second run... and nothing changes.
      
      > f(Number)
      > 3873 // and again
      > f(parseFloat)
      > 3583 // and again
      > f(function(e){return+e})
      > 4967 // and again
      
      > f(function(e){return parseInt(e,10)})
      > 21649 // dammit 'parseInt'! >_<
      

    Notice: In Firefox parseInt works about 4 times faster, but still slower than others. In total: +e < Number < parseFloat < parseInt

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