总结类别中的案例数并计算新列

Question

我有一个具有以下结构的数据集

zip code |type of crime
------   |------
1002     |crime1
1002     |crime1
1002     |crime2
1002     |crime1
9210     |crime1
9210     |crime1
9210     |crime2
9210     |crime2

我还有每个犯罪的最低刑罚清单

crime |  minimum sentence (days)
------| ------
crime1|10
crime2|15

使用这两个表，我想执行以下操作：

1. 计算每个社区中每项犯罪的总数

   zip code | crime    |number of crimes
   ------   | ------   |-----
   1002     |  crime1  | 3
   1002     |  crime2  | 1
   9210     |  crime1  | 2
   9210     |  crime2  | 2
   

2. 将每个犯罪乘以它的最小句子，然后计算邻域的总天数。

   zip  | crime  | crimexdays
   ---- | ------ | -----
   1002 | crime1 | 30
   1002 | crime2 | 15
   9210 | crime1 | 20
   9210 | crime2 | 30
   

我真的很感激这里有任何帮助。干杯!!

Answer 1

使用count获取频率，left_join获取第二个数据集，trasmute创建新列

df1 %>% 
     count(zipcode, typeofcrime) %>% 
     left_join(., df2, by = c("typeofcrime" = "crime")) %>% 
     transmute(typeofcrime, crimexsentence = n*minimumsentence) 
#     zipcode typeofcrime crimexsentence
#     <int>       <chr>          <int>
#1    1002      crime1             30
#2    1002      crime2             15
#3    9210      crime1             20
#4    9210      crime2             30