javascript - find range value between two floats

Question

I have a string like so:

(999.08) - (1025.67)

I need to be able to find the range between these two values as a floting point even if they are negative values so (-999.08) - (-1025.67) would also be in scope.

Assume i would need to use a regex and join the two in some sort of array?

Answer 1

From looking over everyone else's answers, I can't tell if any of them deal with negative numbers properly. I'll throw this in the ring in case anyone needs it.

function parse(str) {

    // init to NaN
    var result = Number.NaN;

    // capture numbers in groups
    var pat = new RegExp(/\((-?\d+.?\d*)\)\s*-\s*\((-?\d+.?\d*)\)/);
    var match = str.match(pat);

    if (match) {
        // match[0] is whole match which is not useful
        var a = new Number(match[1]); // 1st group is 1st number
        var b = new Number(match[2]); // 2nd group is 2nd number
        result = Math.abs(a - b);
    }

    return result;
}

demo: http://jsbin.com/oseba4/edit

Answer 2

You can split the string on the " - " using .split, use replace to remove the brackets, and then parseFloat the two numbers. After that, check for the highest of the two numbers, and subtract for the range.

Answer 3

There are a couple of ways: Here is one: sort of the long way around

var myString = "(999.08) - (1025.67)"

var myFloatValues = mystring.split("-");

myFloatValues[0] = myFloatValues[0].replace("(", "").replace(")", "");
myFloatValues[1] = myFloatValues[1].replace("(", "").replace(")", "");

myFloatValues[0] = parseFloat(myFloatValues[0])
myFloatValues[1] = parseFloat(myFloatValues[1])

Here is using a regex:

var myString = "(999.08) - (1025.67)"
var myFloatValues = (myString.replace(/\(*|\)*|\s*/g, "")).split("-");
myFloatValues[0] = parseFloat(myFloatValues[0])
myFloatValues[1] = parseFloat(myFloatValues[1])

Note: a useful site I have been using for a ling time

This site helps a person generate valid regular Expressions. Give it a try http://www.jslab.dk/tools.regex.php

Answer 4

in addition to John hartsocks answer: add a check after you set the float values to swap around the values if the first value is bigger than the second

function Check(myValue,myString)
{
    var myFloatValues = (mystring.replace(/\(*|\)*|\s*/g, "")).split("-");
    myFloatValues[0] = parseFloat(myFloatValues[0]);
    myFloatValues[1] = parseFloat(myFloatValues[1]);
    if (myFloatValues[0] > myFloatValues[1]) // swap
    {
        var temp = myFloatValues[0];
        myFloatValues[0] = myFloatValues[1];
        myFloatValues[1] = temp;
    }
    if (myFloatValues[0] < myValue && myFloatValues[1] > myValue) // this will be a problem if you dont swap them
        return true;
    return false;
}

Answer 5

Pesuo code:

// Our variables
float num1;
float num2;
string myString = "(999.08) - (1025.67)";

// Split the data string on - character
arrParts[] = myString.split("-");

// Loop through each resulting split
for int i = 0; i < arrParts.Count; i++)
{
   // Trim result to remove whitespace
   arrParts[i] = arrParts[i].trim();

   // Take all the characters in string except first and last
   arrParts[i] = arrParts[i].substring(1, part.length-2);
}

// Cast out numbers
num1 = (float)arrParts[0];
num2 = (float)arrParts[1];

Solution assumptions

Assumes input string is correct format, and that no fewer or more than 2 valid float numbers will be provided.

For range calculation:

Two ways, either subtract either from either and get absolute value to determine range, or take the lengthier method of guaranteeing smaller number is taken for bigger

Notes on regexp

I would argue against using regexp where possible (although this is very subjective) because it can turn reviewing this code in the future into a difficult task.

If you do use regexp make sure you comment in the expected input formats to protect against this.

Answer 6

This is where eval* shows its true power.

range = Math.abs(eval(string));

_{*No, it's NOT evil ;)}