User23 - 9 months ago 31

R Question

I have a large data frame A that has sales figures for different items for only a few weeks and doesn't mention the weeks where no sales occurred. I therefore created a second data frame B where I have included all weeks with sales set to 0. I now want to add B to A but not for the weeks where A already mentions a sale. I was hoping to do this via an added combination variable but can't seem to figure out a fast way to do this.

So I have for example

`A Week ID Sales Combination B Week ID Sales Combination`

1 X 5 1_X 1 X 0 1_X

2 X 6 2_X 2 X 0 2_X

5 X 5 5_X 3 X 0 3_X

6 X 4 6_X 4 X 0 4_X

1 Y 2 1_Y 5 X 0 5_X

3 Y 2 3_Y 6 X 0 6_X

5 Y 2 5_Y 1 Y 0 1_Y

2 Y 0 2_Y

3 Y 0 3_Y

4 Y 0 4_Y

5 Y 0 5_Y

And what I want is this

`Week ID Sales Combination`

1 X 5 1_X

2 X 6 2_X

3 X 0 3_X

4 X 0 4_X

5 X 5 5_X

6 X 4 6_X

1 Y 2 1_Y

2 Y 0 2_Y

3 Y 2 3_Y

4 Y 0 4_Y

5 Y 2 5_Y

Hope this makes it more or less clear.

Answer

Let `dfA`

be the first data.frame, and `dfB`

be the second one, you could do

```
# Get relevant data together
new_df = rbind(dfA, dfB[dfA$Combination != dfB$Combination,])
# Order the data frame
sorting_index = sort(new_df$Combination, index.return=T)
new_df = new_df[sorting.index$ix,]
```

Alternatively, you could set our new data frame as being `dfB`

and then use `match`

to get the values from `dfA`

and put them at the right place.