如果与NaN的比较总是返回false,我如何比较浮点数到NaN？

let num = parseFloat("1.23");
if (isNaN(num)) {
  console.log("The number is NaN");
} else {
  console.log("The number is not NaN");
}

import math

num = float("1.23")
if math.isnan(num):
  print("The number is NaN")
else:
  print("The number is not NaN")

double num = Double.parseDouble("1.23");
if (Double.isNaN(num)) {
  System.out.println("The number is NaN");
} else {
  System.out.println("The number is not NaN");
}

double num = double.Parse("1.23");
if (double.IsNaN(num)) {
  Console.WriteLine("The number is NaN");
} else {
  Console.WriteLine("The number is not NaN");
}