基于因子变量的数据集子设置，可生成与因子长度一样多的子集

# 创建一个示例数据集
data <- data.frame(
  factor_var = factor(c("A", "B", "A", "C", "B", "A")),
  value = c(1, 2, 3, 4, 5, 6)
)

# 显示原始数据集
print(data)

# 根据因子变量的水平创建子集
factor_levels <- levels(data$factor_var)
subsets <- lapply(factor_levels, function(level) {
  subset(data, factor_var == level)
})

# 显示子集
for (i in seq_along(subsets)) {
  cat("Subset for level", factor_levels[i], ":\n")
  print(subsets[[i]])
  cat("\n")
}

[1] "Subset for level A :"
  factor_var value
1         A     1
3         A     3
6         A     6

[1] "Subset for level B :"
  factor_var value
2         B     2
5         B     5

[1] "Subset for level C :"
  factor_var value
4         C     4