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I have a string containing numbers and different mathematical operators. How can I parse this string from var str = "123+45-34"; an convert it to an array

var arr = [123, '+', 45, '-',34];
user2314737
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dadadodo
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  • @WiktorStribiżew: That question isn't the same. it wants to split a string at a set of characters. The criteria here are different. – Cerbrus Nov 09 '16 at 15:19
  • Similar question: [Evaluating a string as a mathematical expression in JavaScript](http://stackoverflow.com/questions/2276021/evaluating-a-string-as-a-mathematical-expression-in-javascript) – user2314737 Nov 09 '16 at 16:22

4 Answers4

1

It looks like you want to split your string on word boundaries:

var str = "123+45-34";
console.log(str.split(/\b/));
Cerbrus
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1

You could use a different approach with an operator object, which could be usefull for calculating the value later.

function split(s) {
    var a = s.split(''),
        i = 1;

    while (i < a.length) {
        if (!(a[i - 1] in operators || a[i] in operators)) {
            a[i - 1] += a.splice(i, 1)[0];
            continue;
        }
        i++;
    }
    return a.map(function (b) {
        return b in operators ? b : +b;
    });
}
var operators = { '+': true, '-': true },
    str = "123+45-34+1e13";

console.log(split(str));
Nina Scholz
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1

One approach would be to split the string using a regex and then convert the parts into numbers where possible:

var str = "123+45-34";

var matches = str.match(/(\d+|\+|-|\/|\*)/g);

console.log(matches); // ["123", "+", "45", "-", "34"]

var asNumbers = matches.map(function(match) {
  return +match || match
})

console.log(asNumbers); // [123, "+", 45, "-", 34]
TimoStaudinger
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  • thanks for the answer could you explain the map function? – dadadodo Nov 10 '16 at 09:01
  • `+match` converts the value into a number, or `NaN` if that's not possible. `NaN` evaluates to the boolean value `false`, in which case the right hand side of the OR statement is executed. It either returns the value converted to a number, or the value as string if it can't be converted. – TimoStaudinger Nov 10 '16 at 16:05
-2

This code tries to traverse through the string.Each charecter is appended into a newstring,until + or - is found,once they are found string formed till now will be pushed into newarray and special charecter either + or - is also pushed into newarray and again this process continues till the end of the string

Ex:123+

it traverses the string. first my newString ="1" ,then newString="12" finally newString="123" as soon as + is found ,it pushes newString into newarray.now newArray is ["123" ] and '+' should also be pushed ,now array becomes ["123","+"].this process continues

Here i have taken into consideration of special charecters as only + and -

var str="123+45-34";
var newarr=[];
var newStr="";
for(var index=0;index<str.length;index++){
  
  if(str[index]!='+'&& str[index]!='-')
    newStr+=str[index];
  else{
    newarr.push(newStr);
    newarr.push(str[index]);
    newStr="";
  }
 
  }
console.log(newarr);

Hope this helps

Geeky
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