Question

我想重塑数据框架。

数据：

             a <- c("A_h:old","A_h:new","A_h:old","A_h:new","A_h:old","A_h:new","A_h:old","A_h:new")
             b <- c("2015-08-11","2015-08-11","2015-08-12","2015-08-12","2015-08-13","2015-08-13","2015-08-14","2015-08-14")
             c <- c(12,10,12,23,16,17,7,9)
             df <- data.frame(a,b,c)

产生：

              a         b          c
              A_h:old  2015-08-11  12
              B_h:new  2015-08-11  10
              A_h:old  2015-08-12  12
              B_h:new  2015-08-12  23
              A_h:old  2015-08-13  16
              B_h:new  2015-08-13  17
              A_h:old  2015-08-14   7
              B_h:new  2015-08-14   9

期望的结果：

                  b        A_h:old   B_h:new
              2015-08-11   12         10
              2015-08-12   12         23
              2015-08-13   16         17
              2015-08-14    7         9

我试图使用：

             reshape(df, timevar = "b", idvar = c(" A_h:old", "B_h:new"), direction = "wide")

失败。

Answer 1

我们可以使用dcast中的reshape2将'long'转换为'wide'

library(reshape2)
dcast(df, b~a, value.var='c')
#           b A_h:new A_h:old
#1 2015-08-11      10      12
#2 2015-08-12      23      12
#3 2015-08-13      17      16
#4 2015-08-14       9       7

如何正确地重塑数据框？

1 个答案: