Why add 1e-7 to stds in Tabular Normalize?

Part 1 (2019)
1

Hello Friends,

Walking through the definition of

class Normalize(TabularProc):

I found the code below,

self.means[n],self.stds[n] = df[n].mean(),df[n].std()
df[n] = (df[n]-self.means[n]) / (1e-7 + self.stds[n])

Any reason to why add 1e-7 to standard deviations before division?

1 Like
2

So you don’t divide by zero which will give an error (or make the all the values `inf`` - infinity). This is commonly called an epsilon, and you’ll see it in most places that divide by a value that could be 0.

3 Likes
3

@TomB

Gotcha! Thanks…