Question

继续收到错误消息：

没有适用于“ summarise_”的适用于“字符”类对象的方法追溯：

我试图将'count ='更改为：

（计数=计数（forest_cover $ Cover_Type）） count = count（Cover_Type）


library(ggplot2)

# # forest_cover data is supplied to group_by() function to group the data based on Cover_Type. 
# # This 7 groups of data formed above is supplied as input to summarize() where we are getting the 
# # count of observations stored in the variable count. cover_type_ratio is created to store the 
# # ratio of cover type. 

coverType_count = forest_cover %>%  
  group_by(Cover_Type) %>%    # data is grouped according to labels (1,2,3,4,5,6,7) of cover type
  dplyr::summarize(count = count(forest_cover$Cover_Type)) %>%  # count the number of observations in each group
  mutate(cover_type_ratio=count/sum(count)) # divide the counts obtained in above step to get the ratio.

# # Display the contents of the variable coverType_count
coverType_count ```

I expect the code to plot a bar graph for the observations of each Cover_Type.

Answer 1

count需要一个tibble/data.frame，并且不在summarise内使用

library(dplyr)
forest_cover %>%
   count(Cover_Type) %>%
   dplyr::mutate(cover_type_ratio = n/sum(n))

如果我们要使用summarise，请在group_by之后使用n()

forest_cover %>%
   group_by(Cover_Type) %>%
   dplyr::summarise(Count = n()) %>%
   dplyr::mutate(cover_type_ratio = Count/sum(Count))

Answer 2

Base R解决方案：

# Count by the group: 

forest_cover$count <- ave(forest_cover$Cover_Type, forest_cover$Cover_Type, FUN = length)

# Calculate the ratio:

forest_cover$cover_type_ratio <- forest_cover$count/nrow(forest_cover)

计算每组中观察值的数量

2 个答案: