R语言决策树剪枝----泰坦尼克数据集计算存活情况CP = Complexity Parameter 复杂度参数> print(tree_full$cptable) CP nsplit rel error xerror xstd 1 0.444444444 0 1.0000000 1.0000000 0.04244576 2 0.030701754 1 0.5555556 0.5555556 0.03574957 3 0.023391813 3 0.4941520 0.5029240 0.03444798 4 0.020467836 4 0.