在js中使用Map，Reduce和filter将华氏温度转换为摄氏度

Question

I have an array of temperatures and i have to convert them to degree celcius , i was told i need to use map/reduce in javascript . I have looked through the documentation but i cant seem to figure out how to do it. Here is my array :

var fahrenheit = [0, 32, 45, 50, 75, 80, 99, 120];

Answer 1

Try to use map in this way,

var fahrenheit = [0, 32, 45, 50, 75, 80, 99, 120];
var celcius = fahrenheit.map(v => ((v - 32) * (5/9)).toFixed(1));
//If you do not want the decimal points then write,
//   fahrenheit.map(v => ((v - 32) * (5/9)) | 0);

console.log(celcius); //["-17.8", "0.0", "7.2", "10.0", "23.9", "26.7", "37.2", "48.9"]

Formula to convert F to C is,

C = ((F - 32) * (5 / 9))

Answer 2

This should work

  var celcius = fahrenheit.map(function(elem) {
        return Math.round((elem - 32) * 5 / 9);
    });

or in ES6

fahrenheit.map(elem => Math.round((elem - 32) * 5 / 9));

and you get

celcius //  [-18, 0, 7, 10, 24, 27, 37, 49]

Answer 3

I guess this shall do it

var fahrenheit = [0, 32, 45, 50, 75, 80, 99, 120],
       celcius = fahrenheit.map(f => (f-32)/1.8);