R中将一个变量拆分为多个变量

Question

我对 R 比较陌生。我的问题并不完全像标题那么简单。这是一个示例df：

id    amenities
1     wireless internet, air conditioning, pool, kitchen
2     pool, kitchen, washer, dryer
3     wireless internet, kitchen, dryer
4     
5     wireless internet

这就是我想要df的样子：

id    wireless internet   air conditioning   pool   kitchen   washer   dryer
1     1                   1                  1      1         0        0
2     0                   0                  1      1         1        1
3     1                   0                  0      1         0        1
4     0                   0                  0      0         0        0
5     1                   0                  0      0         0        0

重现数据的示例代码

df <- data.frame(id = c(1, 2, 3, 4, 5),
      amenities = c("wireless internet, air conditioning, pool, kitchen",  
                    "pool, kitchen, washer, dryer", 
                    "wireless internet, kitchen, dryer", 
                    "", 
                    "wireless internet"), 
      stringsAsFactors = FALSE)

Answer 1

FWIW，这是一个基本的 R 方法（假设df包含问题中所示的数据）

dat <- with(df, strsplit(amenities, ', '))
df2 <- data.frame(id = factor(rep(df$id, times = lengths(dat)),
                              levels = df$id),
                  amenities = unlist(dat))
df3 <- as.data.frame(cbind(id = df$id,
                     table(df2$id, df2$amenities)))

这导致

> df3
  id air conditioning dryer kitchen pool washer wireless internet
1  1                1     0       1    1      0                 1
2  2                0     1       1    1      1                 0
3  3                0     1       1    0      0                 1
4  4                0     0       0    0      0                 0
5  5                0     0       0    0      0                 1

分解正在发生的事情：

1. dat <- with(df, strsplit(amenities, ', '))将amenities变量拆分为', '，结果是

   > dat
   [[1]]
   [1] "wireless internet" "air conditioning"  "pool"             
   [4] "kitchen"          
   
   [[2]]
   [1] "pool"    "kitchen" "washer"  "dryer"  
   
   [[3]]
   [1] "wireless internet" "kitchen"           "dryer"            
   
   [[4]]
   character(0)
   
   [[5]]
   [1] "wireless internet"
   

2. 第二行将dat其转换为向量，然后我们id通过重复原始id值与该 的设施数量一样多的次数来添加 和 列id。这导致

   > df2
      id         amenities
   1   1 wireless internet
   2   1  air conditioning
   3   1              pool
   4   1           kitchen
   5   2              pool
   6   2           kitchen
   7   2            washer
   8   2             dryer
   9   3 wireless internet
   10  3           kitchen
   11  3             dryer
   12  5 wireless internet
   

3. 使用该table()函数创建列联表，然后添加一id列。