Gladly loves figures, so he decides to make a figure showing meatball sales by season. His code is shown below:

d %% 1
ggplot(mapping=aes(x=season,y=meatballs)) + 2
geom_violin() + 3
geom_jitter(colour=season,alpha=0.4) + 4
theme_bw() + 5
scale_fill_brewer(palette="Set1") + 6
labs(title="Meatball sales by season", + 7
x = "Season", y="Meatballs sold") 8

Sadly, there are multiple errors in his code. Which of these lines does NOT contain an error?

Question

Gladly loves figures, so he decides to make a figure showing meatball sales by season. His code is shown below:

d %>%                                           1
  ggplot(mapping=aes(x=season,y=meatballs)) +   2
  geom_violin() +                               3
  geom_jitter(colour=season,alpha=0.4) +        4
  theme_bw() +                                  5
  scale_fill_brewer(palette="Set1") +           6
  labs(title="Meatball sales by season", +      7
       x = "Season", y="Meatballs sold")        8

Sadly, there are multiple errors in his code. Which of these lines does NOT contain an error?

BlackTom AI · Accepted Answer

Because ggplot() accepts the piped data as its first argument, writing ggplot(mapping = aes(x = season, y = meatballs)) after d %>% correctly passes d as the data — so Line 2 is valid.

1) Relevant knowledge points and concepts
- magrittr pipe (%>%) forwards the left-hand side as the first argument of the function on the right. d %>% ggplot(...) is equivalent to ggplot(d, ...).
- ggplot’s mapping argument must be an aes(...) object when mapping variables to aesthetics.
- Aesthetic mappings (colour, fill) must be specified inside aes(...) to map to data variables; outside aes they are treated as constants.
- scale_fill_* applies to the fill aesthetic; scale_color_* (or scale_colour_*) applies to the colour aesthetic.
- The + operator in ggplot must be used between layers/commands; it should appear at the end of a line (or outside a function call), not inside the arguments of a function like labs().

2) Step-by-step reasoning for each candidate line
- Line 2: d %>% ggplot(mapping = aes(x = season, y = meatballs)) — valid. The pipe supplies d as the data argument; mapping is correctly given as aes(...). No syntax or semantic error.
- Line 4: geom_jitter(colour = season, alpha = 0.4) — incorrect because colour = season is outside aes(). To map point colour to the season variable you must use aes(colour = season) or aes(color = season) inside geom_jitter.
- Line 6: scale_fill_brewer(palette = "Set1") — problematic here because no fill aesthetic was mapped. If you intended to color by season and used colour (not fill), you need scale_color_brewer. Alternatively, map fill=season in aes() for geoms that use fill. As written it won’t produce the intended mapping.
- Line 7: labs(title = "Meatball sales by season", + — the plus sign shown inside the function is a syntax error; the + that chains ggplot components must be placed between expressions (e.g., at the end of the previous line), not inside labs()’s argument list.

3) Intermediate steps / checks
- Confirm piping: d %>% ggplot(mapping = aes(...)) → ggplot(d, mapping = aes(...)) — valid substitution.
- Confirm mapping: aes(x=season, y=meatballs) correctly supplies x and y.

4) Why the correct answer is correct
Line 2 conforms to ggplot and magrittr rules: the data is passed correctly via the pipe and mapping is supplied with aes(). There is no misuse of aesthetics or incorrect placement of the + operator in that line.

5) Why the other options are incorrect (brief)
- Line 4: colour mapped outside aes() — should be aes(colour = season).
- Line 6: uses scale_fill_brewer but no fill aesthetic is mapped; likely the wrong scale function for the existing aesthetic.
- Line 7: contains a misplaced + inside labs(), which is a syntax error.

6) Conclusion
The only line among the choices that does NOT contain an error is Line 2, which matches the provided answer: Line 2.

类似问题

na is a vector of numeric elements. You do not know how many elements na has. When you run the following, you are returned 1. sum(is.na(na)) If you execute the following, what would be the output? sum(is.na(na[which(is.na(na))] + na)) ==length(na)

Dharma has vector w in her active R session. There are no missing values in w. That is, there is no NA’s in w. She executed the following code: sum(w) == sum(w[which(w)]) R returned (outputted) TRUE on her R console. TRUE/FALSE: w is not a logical vector.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单