浮点数正在四舍五入

Question

I am experiencing some strange behaviour with float numbers in a javascript array.

When I loop over the array like this:

$.each(values, function(key,data) {
 console.log(key +": "+data);
})

I see the numbers correctly as follows:

4: 39.9283296
spline:167 5: -3.4983312
spline:167 6: 823.487609863281

But when I try to access the data directly using the array index like this:

console.log(data[4] + " " +data[5] + " " +data[6])

The numbers get rounded:

2 8 3

I would really apprecaite it if someone could explain what is going on here, and how I can access the original data. TIA!

Answer 1

Looks like you're trying to access a string like an array. Your data variable contains a string, thus when you call data[4] , you get the 5th character in your string.

There's the parseFloat method for parsing your string into a float, if you want it like that.

Answer 2

I started with the comment, but I'll just write an answer.

You are addressing data and think of it as your array, while in fact that is just one value. Check your first value: 39.9283296 . Indices 4/5/6 are 2/8/3 accordingly. That's what you are seeing, not the "floated" numbers rounded.

Check where you get data from, looks like you just need data itself as your value.

Answer 3

Your code is like this:

$.each(values, function(key,data) {
 console.log(key +": "+data);
})

So let's take a look at the first line of output:

4: 39.9283296

Ok, what is key and what is data ?

key: "4"
data: "39.9283296" // I assume it's string according to result you got

So, what does console.log(data[4] + " " +data[5] + " " +data[6]) give you?

"39.9283296"[4] // 2
     ^
"39.9283296"[5] // 8
      ^
"39.9283296"[6] // 3
       ^

You got it, 2 8 3 .