Question

我正在尝试比较长字符串数字。数字长度在1到50之间。比较字符串的长度效果很好，但如果长度相等则有点困难。我决定将字符串变成数组，并比较值，直到它们不同为止。我认为这是格式错误，但我不确定。

function compareIntegers(a, b) {
  //coding and coding..
  var aSplit = a.split("")
  var bSplit = b.split("")

if (a.length > b.length){
    return "greater";
}
        if (b.length > a.length){
            return 'less';
        }
if (a.length == b.length){ 
        for (i=0; aSplit.length; i++){
            if (bSplit.indexOf(aSplit[i] ===-1) {
                if (aSplit[i] > bSplit[i]){
                    return 'greater';
                    }
        if (aSplit[i] < bSplit[i]){
            return 'less';
            }
     else return 'equal';
         }
     }
}

}
describe("Basic Tests", function(){ 
it("It should works for basic tests.", function(){

Test.assertEquals(compareIntegers("12","13"),"less")

Test.assertEquals(compareIntegers("875","799"),"greater")

Test.assertEquals(compareIntegers("1000","1000"),"equal")

Test.assertEquals(compareIntegers("999","1000"),"less")

Test.assertEquals(compareIntegers("123","122"),"greater")

Test.assertEquals(compareIntegers(
    "1000000000000000000000000000000000",
    "1000000000000000000000000000000001"),
    "less"
)
Test.assertEquals(compareIntegers(
    "1000000000000000000000000000000002",
    "1000000000000000000000000000000001"),
    "greater"
)

Test.assertEquals(compareIntegers(
    "10000000000000000000000000000000000",
    "1000000000000000000000000000000001"),
    "greater"
)

})})

Answer 1

没有理由将字符串拆分为数组，您可以使用索引属性或.charAt()轻松访问单个字符。并且没有理由自己完成这种逐个字符的比较（并且会犯bSplit.indexOf(aSplit[i])这样的错误），这只是比较两个字符串的默认行为。所以我写了

function compareIntegerStrings(a, b) {
  a = a.replace(/^0*/, ""); // strip leading zeroes
  b = b.replace(/^0*/, "");

  if (a.length > b.length){
    return 1;
  } else if (b.length > a.length){
    return -1;
  } else { // a.length == b.length
    if (a > b) {
      return 1;
    } else if (b > a) {
      return -1;
    }
  }
  return 0;
}
function comparisonToString(c) {
  return ['less', 'equal', 'greater'][Math.sign(c)];
}

您还可以将compareIntegerStrings中的比较金字塔缩短为

return Math.sign(a.length - b.length) || +(a>b) || -(a<b);

这会比较JavaScript中的数组吗？

1 个答案: