sanaz - 4 months ago 16

R Question

I have the following data frame:

`label target sale`

low 5000 4000

low 11000 9000

low 5500 4500

low 12000 9500

middle 20000 18000

middle 22000 190000

high 100000 90000

high 120000 95000

I need to first group my data frame by label and then calculate: mean(target - sale) only for rows where target is more than 10000, I tried following code:

`library(dplyr)`

avg_increase <- df %>%

group_by(labels) %>%

summarise(avg_sale_increase = ifelse(target >= 10000,mean(target - sale), 0))

and I get the following error:

Error: expecting a single value

As

`summarise`

`deployer::do`

Answer

The problem is with ifelse, which returns a vector if length equal to the input logical, so the mean is going to be calculated as many times as required.

This should work

```
avg_increase <- df %>%
group_by(labels) %>%
filter(target >= 10000) %>%
summarise(target = mean(target-sale))
```