如何在R中将大量行数庞大的文件从长格式转换为宽格式？

install.packages("reshape2")  # 安装包
library(reshape2)  # 加载包

data_long <- data.frame(
  时间 = rep(1:10, each = 3),  # 时间列
  类别 = rep(c("A", "B", "C"), 10),  # 类别列
  值 = rnorm(30)  # 值列
)

   时间 类别          值
1    1   A -0.9727908
2    1   B  0.5289377
3    1   C  1.7644605
4    2   A  0.5365853
5    2   B -0.1766331
6    2   C  1.4611308
7    3   A -0.6494716
8    3   B  1.2438894
9    3   C -0.2898138
10   4   A -0.4771927
11   4   B  1.1072779
12   4   C  0.8057717
13   5   A  1.6108252
14   5   B -1.8701503
15   5   C  0.6499265
16   6   A -0.0845803
17   6   B  1.1817043
18   6   C -0.2704303
19   7   A  0.1287355
20   7   B  0.0714327
21   7   C -0.4497050
22   8   A  0.0193430
23   8   B  0.0440001
24   8   C -0.6872332
25   9   A  0.4673156
26   9   B  0.4485805
27   9   C  0.5328565
28  10   A -0.7503902
29  10   B  0.2697634
30  10   C -0.6169925

data_wide <- dcast(data_long, 时间 ~ 类别, value.var = "值")

   时间           A          B          C
1    1 -0.9727908  0.5289377  1.7644605
2    2  0.5365853 -0.1766331  1.4611308
3    3 -0.6494716  1.2438894 -0.2898138
4    4 -0.4771927  1.1072779  0.8057717
5    5  1.6108252 -1.8701503  0.6499265
6    6 -0.0845803  1.1817043 -0.2704303
7    7  0.1287355  0.0714327 -0.4497050
8    8  0.0193430  0.0440001 -0.6872332
9    9  0.4673156  0.4485805  0.5328565
10  10 -0.7503902  0.2697634 -0.6169925