Hello Flynn. I tried to use your autocorrelation function, but found a strange thing, it returns very similar and incorrect values for some lags.
Example:
We have the following sequence:
[22, 24, 25, 25, 28, 29, 34, 37, 40, 44, 51, 48, 47, 50, 51]
In this case we must obtain the following sequence of values of the autocorrelation function:
[1, 0.83174224, 0.65632458, 0.49105012, 0.27863962, 0.03102625, -0.16527446, -0.30369928, -0.40095465, -0.45823389, -0.45047733]
For lags 0,1,2,3... respectively.
But your function return that:
[0, 0.8317422434367543, 0.8871917263325378, 0.8908883585255901, 0.8911348006717935,...]

for i := 0; i < lags; i++ {
	v := (data[0] - mean) * (data[0] - mean)
	for i := 1; i < len(data); i++ {
		delta0 := data[i-1] - mean
		delta1 := data[i] - mean
		q += (delta0*delta1 - q) / float64(i+1)
		v += (delta1*delta1 - v) / float64(i+1)
	}
	result = q / v
}

And in your function there is this strange loop through the lag range, in which you overwrite the value of the variable