Python Pandas CategoricalIndex - 添加新类别

要添加新类别，请使用add_categories()Pandas中的CategoricalIndex方法。首先，导入所需的库-

import pandas as pd

使用“categories”参数设置分类的类别。使用“ordered”参数按顺序处理分类-

catIndex = pd.CategoricalIndex(["p", "q", "r", "s","p", "q", "r", "s"], ordered=True, categories=["p", "q", "r", "s"])

显示分类索引-

print("CategoricalIndex...\n",catIndex)

使用add_categories().添加新类别。将新类别设置为参数。新类别将包含在类别的最后/最高位置-

print("\nCategoricalIndex after adding new categories...\n",catIndex.add_categories(["a", "b", "c", "d"]))

示例

以下是代码-

import pandas as pd #CategoricalIndex只能采用有限且通常是固定数量的可能值（类别 # Set the categories for the categorical using the "categories" parameter # Treat the categorical as ordered using the "ordered" parameter catIndex = pd.CategoricalIndex(["p", "q", "r", "s","p", "q", "r", "s"], ordered=True, categories=["p", "q", "r", "s"]) #显示分类索引 print("CategoricalIndex...\n",catIndex) #获取类别 print("\nDisplayingCategories from CategoricalIndex...\n",catIndex.categories) #使用add_categories()添加新类别 #将新类别设置为参数 #新类别将包含在类别的最后/最高位置 print("\nCategoricalIndex after adding new categories...\n",catIndex.add_categories(["a", "b", "c", "d"]))输出结果

这将产生以下输出-

CategoricalIndex... CategoricalIndex([p, q, r, s, p, q, r, s], categories=[p, q, r, s], ordered=True, dtype=category) DisplayingCategories from CategoricalIndex... Index([p, q, r, s], dtype=object) CategoricalIndex after adding new categories... CategoricalIndex([p, q, r, s, p, q, r, s], categories=[p, q, r, s, a, b, c, d], ordered=True, dtype=category)