On 10/01/2015 23:10, Sebastian Zartner wrote:
While Math.sum() and Math.mean() currently don't exist, they can easily be
polyfilled:
See
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce#Sum_all_the_values_of_an_array
for summarizing the values of an array and the following code for building the
average of the array values:
let arr = [0, 1, 2, 3];
let total = arr.reduce(function(a, b) {
return a + b;
});
let mean = total / arr.length;
Calculating the variance and standard deviation would require a bit more code,
though are also easy to polyfill.
Non-the-less I can see the need for having standard functions for this.
Sebastian
Yes, Math.sum can be polyfilled, but doing so if you want accurate answers
takes a fair amount of care. The code above is pretty bad as a polyfill
because it sometimes produces highly inaccurate answers. For example, if arr =
[1, 1e18, -1e18], then this polyfill will return the incorrect value 0 for
total, while a more careful implementation would return 1.
Waldemar
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