Python Pandas – 將 DataFrame 與多對一關係合併
要合併 Pandas DataFrame,請使用 merge() 函式。透過在 merge() 函式的 “validate” 引數下進行設定,在兩個 DataFrames 上實現 多對一關係,即 −
validate = “many-to-one” or validate = “m:1”
多對一關係檢查 merge 鍵在右側資料集中的唯一性。
首先,讓我們建立我們的第 1 個 DataFrame −
dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],"Units": [100, 110, 80, 110, 90] } )
現在,讓我們建立我們的第 2 個 DataFrame −
dataFrame2 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Tesla', 'Mustang', 'Mercedes', 'Jaguar'],"Reg_Price": [7000, 1500, 5000, 8000, 9000, 6000] } )
示例
以下是程式碼 −
# # Merge Pandas DataFrame with many-to-one relation # import pandas as pd # Create DataFrame1 dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],"Units": [100, 110, 80, 110, 90] } ) print("DataFrame1 ...\n",dataFrame1) # Create DataFrame2 dataFrame2 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Tesla', 'Mustang', 'Mercedes', 'Jaguar'],"Reg_Price": [7000, 1500, 5000, 8000, 9000, 6000] } ) print("\nDataFrame2 ...\n",dataFrame2) # merge DataFrames with "many-to-one" in "validate" parameter mergedRes = pd.merge(dataFrame1, dataFrame2, validate ="many_to_one") print("\nMerged dataframe with many-to-one relation...\n", mergedRes)
輸出
這將產生以下輸出 −
DataFrame1 ... Car Units 0 BMW 100 1 Audi 110 2 Mustang 80 3 Bentley 110 4 Jaguar 90 DataFrame1 ... Car Reg_Price 0 BMW 7000 1 Lexus 1500 2 Tesla 5000 3 Mustang 8000 4 Mercedes 9000 5 Jaguar 6000 Merged dataframe with many-to-one relation... Car Units Reg_Price 0 BMW 100 7000 1 Mustang 80 8000 2 Jaguar 90 6000
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