gibbz00 - 2 months ago 23

R Question

This is what my data.table looks like. The A:E columns are just to draw comparison to excel. Column

`NewShares`

`A B C D E F`

dt<-fread('

InitialShares Level Price Amount CashPerShare NewShares

1573.333 0 9.5339 13973.71 0 1573.333

0 1 10.2595 0 .06689 1584.73

0 1 10.1575 0 .06689 1596.33

0 1 9.6855 0 .06689 1608.58')

I am trying to calculate

`NewShares`

`InitialShares`

`NewShares*CashPershare`

`Price*.9`

`=F2+((F2*E3*B3)/(C3*0.9))`

`InitialShares`

In R land, I am trying(which is not quite right):

`dt[,NewShares:= cumsum(InitialShares[1]*Level * CashPerShare/(Price*.9)+InitialShares[1])]`

Please pay attention to the Decimal points of

`NewShares`

Answer

If you expand your formula, you'll realize that this works:

```
dt[, NewShares := cumprod(1+Level*CashPerShare/Price/0.9)*InitialShares[1]]
```