将列（长）的级别重新整理为新列（宽）(Reshape levels of a column (long) into new columns (wide))

 我想在一个DF中获取一列的级别，并将每个级别添加为新DF中的新列。 这是一个玩具数据集，显示源和理想目标DF。 
 
 来源DF 
 
person  hour  ride 
Bill     1      A
Sue      2      B
Bob      1      C
Jill     3      B
Dan      3      A
Tina     3      A
 
 映射DF 
 
hour   A   B   C   Saturation 
1      1   0   1     .66
2      0   1   0     .33
3      1   1   0     .66
 
 这是一个测试数据集： 
 
test_data <- cbind.data.frame(person = c('Bill', 'Sue', 'Bob', 'Jill', 'Dan', 'Tina'),
                              hour = factor(c(1, 2, 1, 3, 3, 3)),
                              ride = c('A', 'B', 'C', 'B', 'A', 'A'))

test_data$person <- as.character(test_data$person)
 
 了解Source每次骑行如何变成Mapped的新列。 我可以获得级别并使用它们来创建映射的DF via 
 
new_data <- cbind.data.frame(hour = levels(test_data$hour))
 
 但是当我尝试迭代级别来添加新列时，它都失败了。 我看到了水平。 
 
unlist(lapply(levels(test_data$ride), function(x) paste(x)))
 
 产量 
 
[1] "A" "B" "C"
 
 那么如何通过$ride的级别并在映射的DF中添加一列？ 
 
 奖励：我将遍历test_data和ifelse()的每一行，对应于该骑行的列中的1表示它有骑手，否则为0 ，但有人必须看到如何更优雅地执行此操作？ 就目前而言，我需要从$ride的级别中提取的每个列都有一个ifelse ，我知道它必须比需要的更冗长。 

I want to take the levels of a column in one DF and add each level as a new column in a new DF. Here is a toy dataset showing the source and ideal target DFs.
 
Source DF
 
person  hour  ride 
Bill     1      A
Sue      2      B
Bob      1      C
Jill     3      B
Dan      3      A
Tina     3      A
 
Mapped DF
 
hour   A   B   C   Saturation 
1      1   0   1     .66
2      0   1   0     .33
3      1   1   0     .66
 
Here is a test data set:
 
test_data <- cbind.data.frame(person = c('Bill', 'Sue', 'Bob', 'Jill', 'Dan', 'Tina'),
                              hour = factor(c(1, 2, 1, 3, 3, 3)),
                              ride = c('A', 'B', 'C', 'B', 'A', 'A'))

test_data$person <- as.character(test_data$person)
 
See how each ride in Source turns into a new column in Mapped. I can get levels and use them to create a mapped DF via
 
new_data <- cbind.data.frame(hour = levels(test_data$hour))
 
but it all fails when I try to iterate through levels to add new columns. I see the levels.
 
unlist(lapply(levels(test_data$ride), function(x) paste(x)))
 
yields
 
[1] "A" "B" "C"
 
So how to go through the levels in $ride and add a column in the mapped DF?
 
Bonus: I am going to run through each of the rows in test_data and ifelse() a 1 in the column that corresponds to that ride to show it had a rider, and a 0 otherwise, but someone must see how to do this more elegantly? As it stands, I would need an ifelse for every column extracted from the levels in $ride which I know has to be more verbose than required.

原文：https://stackoverflow.com/questions/38820039