數據表3列

Question

如何轉換數據集有3列，例如：

V1 V2 V3 
X AB 6 
X EF 5 
Y CD 7 
Z EF 8 
A JK 9 
B LM 10 
B JK 6 

要：

AB CD EF JK LM 
X 6 0 5 0 0 
Y 0 7 0 0 0 
Z 0 0 8 0 0 
A 0 0 0 9 0 
B 0 0 0 6 10 

Answer 1

可以使用

library(reshape2) 
dcast(df, V1~V2, fill=0, value.var="V3") 
## V1 AB CD EF JK LM 
## 1 A 0 0 0 9 0 
## 2 B 0 0 0 6 10 
## 3 X 6 0 5 0 0 
## 4 Y 0 7 0 0 0 
## 5 Z 0 0 8 0 0 

或獲得矩陣使用

acast(df, V1~V2, value.var='V3', fill=0) 

Answer 2

按照由@akrun建議，你可以使用基礎R：

xtabs(V3~V1+V2, df) 

其中給出：

# V2 
#V1 AB CD EF JK LM 
# A 0 0 0 9 0 
# B 0 0 0 6 10 
# X 6 0 5 0 0 
# Y 0 7 0 0 0 
# Z 0 0 8 0 0 

或者使用tidyr

library(tidyr) 
spread(df, V2, V3, fill = 0) 

其中給出：

# V1 AB CD EF JK LM 
#1 A 0 0 0 9 0 
#2 B 0 0 0 6 10 
#3 X 6 0 5 0 0 
#4 Y 0 7 0 0 0 
#5 Z 0 0 8 0 0 

個

---

數據

structure(list(V1 = structure(c(3L, 3L, 4L, 5L, 1L, 2L, 2L), .Label = c("A", 
"B", "X", "Y", "Z"), class = "factor"), V2 = structure(c(1L, 
3L, 2L, 3L, 4L, 5L, 4L), .Label = c("AB", "CD", "EF", "JK", "LM" 
), class = "factor"), V3 = c(6L, 5L, 7L, 8L, 9L, 10L, 6L)), .Names = c("V1", 
"V2", "V3"), class = "data.frame", row.names = c(NA, -7L))