我有一个数据框架,如下所示:
structure(list(ab = c(0, 1, 1, 1, 1, 0, 0, 0, 1, 1), bc = c(1,
1, 1, 1, 0, 0, 0, 1, 0, 1), de = c(0, 0, 1, 1, 1, 0, 1, 1, 0,
1), cl = c(1, 2, 3, 1, 2, 3, 1, 2, 3, 2)), .Names = c("ab", "bc",
"de", "cl"), row.names = c(NA, -10L), class = "data.fra