創建基於關閉索引列

Question

我有兩個數據集：

# 1. 
user_id users frequency 
1  1  3 
2  1  1 
3  1  1 

# 2. 
user_id sum  unique 
1  2  1 
2  0  0 
3  1  1 

我想在user_id合併，而是基於在一個有序的方式使輸出看起來像1單元有指標，留下user_id出來的圖片：

# 3. 
frequency users sum unique 
3   1  2  1 
1   2  1  1 

有關如何實現此目的的想法？而且，就學習如何進行這些類型的操作而言，他們是這種類型操作的名稱嗎？

Answer 1

library(data.table) 
setDT(df)   # this step was to make it a data.table, if its a data.frame 
setDT(df1) 

# logic is : first merge both df's, then group by "frequency" columns 
df[df1][, lapply(.SD, sum), by = .(frequency), .SDcols = c("sum", "unique", "users")] 
# frequency sum unique users 
#1:   3 2  1  1 
#2:   1 1  1  2 

Answer 2

這是一個使用tidyverse的選項。我們可以做兩個數據集，通過「頻率」組合之間的inner_join，我們得到的變量sum內summarise_each

library(dplyr) 
inner_join(df1, df2) %>% 
     group_by(frequency) %>% 
     summarise_each(funs(sum), sum, unique, users) 
# frequency sum unique users 
#  <int> <int> <int> <int> 
#1   1  1  1  2 
#2   3  2  1  1 

---

或者使用base R，我們merge數據集，做一個aggregate

aggregate(.~frequency, merge(df1, df2)[-1], FUN = sum) 
# frequency users sum unique 
#1   1  2 1  1 
#2   3  1 2  1