Hi,

I’m working on the 1985 Cars Dataset and I’m stuck on #9 – https://www.codecademy.com/courses/learn-r/projects/1985-cars-r-project

My code:

#
Task 9

```
# filter rows
cars %>%
filter(mpg_diff_from_threshold > 0)
Errors message:
# filter rows
cars %>%
filter(mpg_diff_from_threshold > 0)
Error: Problem with `filter()` input `..1`.
ℹ Input `..1` is `mpg_diff_from_threshold > 0`.
✖ object 'mpg_diff_from_threshold' not found
Please halp!
```

This error is telling you that there’s no “mpg_diff_from_threshold” column. I guess that the problem is that you didn’t **save the dataframe with the new created column** to the variable “cars” when you created it in the **Task 8**.

The code ill be something like this:

```
# Task 8
# add column of highway_mpg
cars <- cars %>% # I guess this is the part that you missed. Save the new dataframe to the variable "cars"
mutate(mpg_diff_from_threshold = highway_mpg - mpg_threshold) # Add the new column
# Task 9
# filter rows
new_variable <- cars %>%
filter(mpg_diff_from_threshold > 0)
head(new_variable) #To inspect the new dataframe
```

4 Likes

Awesome, you’re a champion!

Does anybody have the answer for 10? I don’t understand what I did wrong.

cars %>%

filter(mpg_exceeds_threshold=) %>%

arrange(desc(mpg_diff_from_threshold))

cars ← cars %>%

arrange(mpg_exceeds_threshold = desc(mpg_diff_from_threshold))

I believe this is correct, or at least it’s not giving me an error code and it makes sense to me!

Please Help! I’m having trouble with Task 4 and Task 6.

#
Task 4

```
# select columns
cars <- cars %>%
select(-normalized_losses)
Error: Can't subset columns that don't exist.
✖ Column `normalized_losses` doesn't exist.
# Task 6
```{r error=TRUE}
# rename column
cars <- cars %>%
rename(risk_factor = symboling)
colnames(cars)
It keeps saying error every time I Save it
```