R变换数据帧

Question

我有下表：

Account.Code    Brand       
1600    Sensodyne TP        
1600    Sensodyne TP        
1600    Zem     
1600    Sensodyne TP        
1800    Sensodyne TP        
1800    Burb MN     
1800    Burb MN     
2000    Lami        
2000    Lami        

如何转换为如下所示的表：

Account.Code    Brand   Count
1600    Sensodyne TP    3
1600    Zem             1
1800    Sensodyne TP    1
1800    Burb MN         2
2000    Lami            2

我需要做一个更大的数据集，只是一个简单的例子。

Answer 1

使用dplyr：

library(dplyr)

df %>%
  group_by(Account.Code, Brand) %>%
    summarise(count = n())

#  Account.Code        Brand count
#         <int>       <fctr> <int>
#1         1600 Sensodyne_TP     3
#2         1600          Zem     1
#3         1800      Burb_MN     2
#4         1800 Sensodyne_TP     1
#5         2000         Lami     2

Answer 2

或基础R解决方案

df$Count = 1
aggregate(Count ~ Account.Code + Brand, data=df, FUN=length)
  Account.Code        Brand Count
1         1800      Burb MN     2
2         2000         Lami     2
3         1600 Sensodyne TP     3
4         1800 Sensodyne TP     1
5         1600          Zem     1