Python Pandas - 基於底層分類建立索引
要基於底層分類建立索引,請使用 **pandas.CategoricalIndex()** 方法。
首先,匯入所需的庫 −
import pandas as pd
CategoricalIndex 是基於底層分類的索引。CategoricalIndex 可以採用有限的(通常是固定的)數量的可能值。使用“categories”引數設定分類的類別。使用“ordered”引數將分類視為有序 −
catIndex = pd.CategoricalIndex( ["p", "q", "r", "s","p", "q", "r", "s"], ordered=True, categories=["p", "q", "r", "s"] )
顯示分類索引 −
print("Categorical Index...\n",catIndex)
獲取分類 −
print("\nDisplayingCategories from CategoricalIndex...\n",catIndex.categories)
示例
以下是程式碼 −
import pandas as pd # CategoricalIndex is the Index based on an underlying Categorical # 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"] ) # Display the Categorical Index print("Categorical Index...\n",catIndex) # Get the categories print("\nDisplayingCategories from CategoricalIndex...\n",catIndex.categories) # Get the min value print("\nMinimum value from CategoricalIndex...\n",catIndex.min()) # Get the max value print("\nMaximum value from CategoricalIndex...\n",catIndex.max())
輸出
這將產生以下輸出 −
Categorical Index... 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') Minimum value from CategoricalIndex... p Maximum value from CategoricalIndex... S
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