为什么这种缩放不起作用？

Question

Currently I am trying to scale a data to a size to fit between two numbers. My code is as below:

function dataScaling(db,rangeMax,rangeMin,value) {

  var min = db[1].FIELD1;
  var max = min;

  for (var i=2; i < db.length; i++) {
    if (db[i].FIELD1 < min) {min = db[i].FIELD1;}
    if (db[i].FIELD1 > max) {max = db[i].FIELD1;}
  }

  var percent = (value - min) / (max - min);
  var answer = percent * (rangeMax - rangeMin) + rangeMin;
  return answer;

}

Now when I run:

console.log("Min = "+min);
console.log("Maz = "+max);

and if (answer > rangeMax) {console.log("Value is Too BIG: "+answer );} , I get:

Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:171 Value is Too BIG: 57.38461538461539
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:171 Value is Too BIG: 49.07692307692308
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:171 Value is Too BIG: 29.692307692307693
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000
index.js:166 Min = 0
index.js:167 Maz = 6500000

The very first time and for the second time, I get:

index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:171 Value is Too BIG: 139.14285714285714
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:171 Value is Too BIG: 96.28571428571429
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:171 Value is Too BIG: 87.71428571428571
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000
index.js:166 Min = 0
index.js:167 Maz = 21000000

It must be noted that the input to dataScaling function ( db ) is constantly changing every time I run the program. What I don't understand, is the data exceeding the ranges. I call the function using this:

dataScaling(initialArray,20,2,d.FIELD1);

Answer 1

I'm not sure what you're looking for, but I think this is your solution.

 /** * Re-maps a number from one range to another. * @param {number} value Value to be converted. * @param {number} min1 Lower bound of the value's current range. * @param {number} max1 Upper bound of the value's current range. * @param {number} min2 Lower bound of the value's target range. * @param {number} max2 Upper bound of the value's target range. * @returns {number} */ function Map(value, min1, max1, min2, max2) { return ((value - min1) / (max1 - min1)) * (max2 - min2) + min2; } // Lets say this is percentiles let foo = 25; // You want the percentiles to a scale from 0 to 2 let doo = Map(foo, 0, 100, 0, 2) console.log(doo); // From the scale 0-2 back to percentiles. console.log(Map(doo, 0, 2, 0, 100)); 

Answer 2

You never say or check that d.FIELD1 (ie value argument) is within min and max .

BTW, what about db[0].FIELD1 ?