dplyr：将data_frame随机分为两个

Question

How can I split a data_frame randomly into two without creating an index? sample_n works for me to get one part of it, but how can I collect the other part?

Answer 1

You can do an anti_join with the extracted part as y-dataframe and the original as x-dataframe. A small example:

library(dplyr)

df <- data_frame(x=1:20,y=runif(20))
dfy <- df %>% sample_n(10, replace=FALSE)
dfx <- anti_join(df, dfy, by="x")

this results in the following dataframes:

> df
Source: local data frame [20 x 2]

    x          y
1   1 0.64147504
2   2 0.35766839
3   3 0.44875782
4   4 0.01905876
5   5 0.85655599
6   6 0.88191481
7   7 0.46532067
8   8 0.09831802
9   9 0.31158184
10 10 0.39504048
11 11 0.81358862
12 12 0.41702158
13 13 0.80441008
14 14 0.69928890
15 15 0.19040897
16 16 0.94120853
17 17 0.65289448
18 18 0.46844427
19 19 0.63177479
20 20 0.58288923

the one half:

> dfx
Source: local data frame [10 x 2]

    x         y
1  19 0.6317748
2  17 0.6528945
3  16 0.9412085
4  15 0.1904090
5  14 0.6992889
6  11 0.8135886
7   7 0.4653207
8   6 0.8819148
9   5 0.8565560
10  3 0.4487578

the other half:

> dfy
Source: local data frame [10 x 2]

    x          y
1  18 0.46844427
2   8 0.09831802
3  12 0.41702158
4   4 0.01905876
5   2 0.35766839
6  10 0.39504048
7  13 0.80441008
8   9 0.31158184
9   1 0.64147504
10 20 0.58288923