如何在模式中標記唯一的事件，因爲這些值在同時發生時是唯一的，而不是在它們分開時發生。

Question

假設我的數據是這樣的

student article.bought 
1  A   pen 
2  B   pencil 
3  V   book 
4  A   pen 
5  A  inkbottle 
6  B   pen 
7  B   pencil 
8  B   pencil 
9  V   book 
10  Z   marker 
11  A  inkbottle 
12  V   book 
13  V   pen 
14  V   book 

我需要的物品獨特的出現可能是像一個不同的專欄，

student article.bought Occurences 
1  A   pen   1 
2  B   pencil   1 
3  V   book   1 
4  A   pen   1 # as A is taking a pen again 
5  A  inkbottle   2 # 'A' changed from pen to ink bottle 
6  B   pen   2 
7  B   pencil   3 # though B took pencil before, this is different as he took a pen in between 
8  B   pencil   3 
9  V   book   1 
10  Z   marker   1 
11  A  inkbottle   2 
12  V   book   1 
13  V   pen   2 
14  V   book   3 

Answer 1

在R，我們可以通過尋找差異，diff，每個後續價值的發現學生的選擇更改。當我們獲得該邏輯索引的累計總和cumsum時，我們得到了發生次數的計數。

在第二行中，我們強制將因子變量article.bought設置爲numeric，並使用ave從第一行開始運行函數，以按學生對函數f進行分組。

f <- function(x) cumsum(c(F, diff(x) != 0)) + 1 
df$Occurences <- with(df, ave(as.numeric(article.bought), student, FUN=f)) 
df 
# student article.bought Occurences 
# 1  A   pen   1 
# 2  B   pencil   1 
# 3  V   book   1 
# 4  A   pen   1 
# 5  A  inkbottle   2 
# 6  B   pen   2 
# 7  B   pencil   3 
# 8  B   pencil   3 
# 9  V   book   1 
# 10  Z   marker   1 
# 11  A  inkbottle   2 
# 12  V   book   1 
# 13  V   pen   2 
# 14  V   book   3 

Answer 2

1. 創建附加列[原創排序]和1 枚舉...
2. 按學生/原始排序順序排列表
3. enter =IF(A2=A1,IF(B2=B1,D1,D1+1),1)在D2和
4. 將列d複製到值（複製，粘貼爲...值）
5. 恢復原來的排序順序

如果這是不是一次性的多，使用相同的策略創建一個VBA腳本

Answer 3

一個鏡頭與SAS：

data try00; 
length student article $20; 
infile datalines dlm=' '; 
input student $ article $; 
datalines; 
A pen 
B pencil 
V book 
A pen 
A inkbottle 
B pen 
B pencil 
B pencil 
V book 
Z marker 
A inkbottle 
V book 
V pen 
V book 
; 

data try01; 
set try00; 
pos=_n_; 
run; 

proc sort data=try01 out=try02; by student pos article; run; 

proc sort data=try02 out=stud(keep=student) nodupkey; by student; run; 

data shell; 
length occurrence 8.; 
set try02; 
if _n_>0 then delete; 
run; 

%macro loopstudent(); 

data _null_; set stud end=eof; if eof then call symput("nstu",_n_); run; 


%do i=1 %to &nstu; 
data _null_; set stud; if _n_=&i then call symput("stud&i",student); run; 

data thisstu; 
set try02; 
where student="&&stud&i"; 
dummyart=lag(article); 
retain occurrence 0; 
if dummyart ne article then occurrence=occurrence+1; 
else occurrence=occurrence; 
drop dummyart; 
run; 

proc append base=shell data=thisstu; run; 

%end; 

proc sort data=shell out=final; by pos; run; 

%mend loopstudent; %loopstudent(); 

數據集 「最後的」 有結果。