如何使用 AutoHotKey 脚本将数字（价格）转换为 0.05 的倍数？

Question

I was automating a trading software using AHK script. During price submission the app does not accept in between values, say between 1.50 and 1.55. It only accepts multiples of 0.05 because its tick-size is 0.05 hence i have to do the price conversion using AHK script.

Answer 1

You can just use

Round(N / 0.05) * 0.05

Example

Round(1.53 / 0.05) * 0.05 ; Returns 1.55

Explanation

I'm going to explain with 0.01 because it's easier to visualize, but it applies to any number. The number to round is 1.234. Anything after 3 will need to be discarded in the rounding process.

If we divide the number 1.234 by 100, we get 123.4. Note how the period is after 3. So we can just use Round now.

After rounding, the number is 123. Now we just need to scale it back down by multiplying by 0.01, which results in 1.23.

Formatting

As 0x464e pointed out in the comments, due how floating-point numbers work, the result may be imprecise. So if you're going to convert them to strings, do so using Format("{:.2f}", number) .

The 2 comes from the minimum number of decimal places needed to accurately represent any number multiple of 0.05. By the way, this can be calculated by using:

Ceil(Log(1 / 0.05)) ; Returns 2

Answer 2

The following AHK function Roundoff converts and returns the price in its nearest tick-size multiple.

Roundoff(price) ;round off to nearest 5 paisa value
{
    price := Round(price, 2) ;ronded to 2 decimal places
    priceNoDecimal := Floor(price)
    decimalPart :=  price - priceNoDecimal
    decimalPart := Floor( Round(decimalPart * 100, 2) )
    numerator := Floor(decimalPart / 5)
    remainder := Mod(decimalPart, 5)
    if ( remainder > 2)
        retval := (numerator * 5) + 5
    if ( remainder < 3)
        retval := (numerator * 5)
    retval := Round(priceNoDecimal + (retval / 100), 2)
    return retval
}