Round numbers to any decimal place

[sergeevabc]

Dear @PaddiM8, let's say there is a file, it takes up 12 350 976 bytes, I want to see how much it is in megabytes, but at the same time round it to the nearest tenths or hundredths. Truncate does not fit.

$ kalker 12 350 976/1024/1024
≈ 11.7788085938

$ kalker truncate(12 350 976/1024/1024, 2)
≈ 11.7

$ kalker some_magic_command(12 350 976/1024/1024)
= 11.8

[PaddiM8]

Maybe there should be a built-in function for that, but you can also add something like this yourself

roundTo(x, p) = round(x * 10^(p - 1)) / 10^(p - 1)

[sergeevabc]

@PaddiM8, come on, rounding is a must have function.

Example

We need to calculate how many percent the file size has increased.

Old file is 4816910 bytes, new file is 6829070 bytes.

$\frac{(New−Old)}{Old}×100$

$ kalker (6829070-4816910)/4816910*100
≈ 41.7728377736

But in everyday life, we often don't need such precision.

In particular, when I fill out reports, a rounded value is expected.

Workaround

$ node -p "parseFloat((6829070-4816910)/4816910*100).toFixed(2)"
41.77

$ node -p "parseFloat((6829070-4816910)/4816910*100).toFixed(0)"
42