每隔一列的数据框

Question

我有一个 df1 数据框，我想创建 df2 和 df3，其原则是每隔一列从 4 列获取 (df2)，从 5 列获取每一列 (df3)。

#df1
aaa <- c("EU", "EU", "IN", "GR")
bbb <- c("AU", "PL", "IN", "ES")
ccc <- c(1, 2, 3, 4)
h0 <- c(2, 2, 3, 4)
h1 <- c(3, 4, 3, 1)
h2 <- c(3, 5, 5, 5)
h3 <- c(3, 5, 5, 5)
h4 <- c(3, 5, 5, 5)
h5 <- c(3, 5, 5, 5)
#..
#hn

#df2
aaa <- c("EU", "EU", "IN", "GR")
bbb <- c("AU", "PL", "IN", "ES")
ccc <- c(1, 2, 3, 4)
h0 <- c(2, 2, 3, 4)
h2 <- c(3, 5, 5, 5)
h4 <- c(3, 5, 5, 5)

#df3
aaa <- c("EU", "EU", "IN", "GR")
bbb <- c("AU", "PL", "IN", "ES")
ccc <- c(1, 2, 3, 4)
h1 <- c(3, 4, 3, 1)
h3 <- c(3, 5, 5, 5)
h5 <- c(3, 5, 5, 5)

Answer 1

这是另一种基于奇数列和偶数列的解决方案：

df1 <- data.frame(aaa, bbb, ccc, h0, h1, h2, h3, h4, h5)

df2 <- df1[ , c(1:3, c(4:ncol(df1))[c(4:ncol(df1)) %% 2 == 0])]
df2
  aaa bbb ccc h0 h2 h4
1  EU  AU   1  2  3  3
2  EU  PL   2  2  5  5
3  IN  IN   3  3  5  5
4  GR  ES   4  4  5  5

df3 <- df1[ , c(1:3, c(4:ncol(df1))[c(4:ncol(df1)) %% 2 == 1])]
df3
  aaa bbb ccc h1 h3 h5
1  EU  AU   1  3  3  3
2  EU  PL   2  4  5  5
3  IN  IN   3  3  5  5
4  GR  ES   4  1  5  5

Answer 2

你可以试试

df <- data.frame(aaa, bbb, ccc, h0, h1, h2, h3, h4, h5)

df[,c(T, T, T, rep(c(T, F), length.out = ncol(df)-3))]
  aaa bbb ccc h0 h2 h4
1  EU  AU   1  2  3  3
2  EU  PL   2  2  5  5
3  IN  IN   3  3  5  5
4  GR  ES   4  4  5  5
df[,c(T, T, T, rep(c(F, T), length.out = ncol(df)-3))]
  aaa bbb ccc h1 h3 h5
1  EU  AU   1  3  3  3
2  EU  PL   2  4  5  5
3  IN  IN   3  3  5  5
4  GR  ES   4  1  5  5