要合并 Pandas DataFrame,请使用merge () 函数。通过在函数的“如何”参数下设置,在两个数据帧上实现左外连接,merge()即 -
how = “left”
首先,让我们使用别名导入 pandas 库 -
import pandas as pd
让我们创建两个要合并的数据帧 -
# 创建 DataFrame1 dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],"Units": [100, 150, 110, 80, 110, 90] } ) # 创建 DataFrame2 dataFrame2 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Tesla', 'Mustang', 'Mercedes', 'Jaguar'],"Reg_Price": [7000, 1500, 5000, 8000, 9000, 6000] } )
将 DataFrames 与公共列 Car 和“how”参数中的“left”合并实现 Left Outer Join -
mergedRes = pd.merge(dataFrame1, dataFrame2, on ='Car', how ="left")
以下是代码 -
import pandas as pd # 创建 DataFrame1 dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],"Units": [100, 150, 110, 80, 110, 90] } ) print"DataFrame1 ...\n",dataFrame1 # 创建 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 common column Car and "left" in "how" parameter implements Left Outer Join mergedRes = pd.merge(dataFrame1, dataFrame2, on ='Car', how ="left") print"\nMerged dataframe with left outer join...\n", mergedRes输出结果
这将产生以下输出 -
DataFrame1 ... Car Units 0 BMW 100 1 Lexus 150 2 Audi 110 3 Mustang 80 4 Bentley 110 5 Jaguar 90 DataFrame2 ... Car Reg_Price 0 BMW 7000 1 Lexus 1500 2 Tesla 5000 3 Mustang 8000 4 Mercedes 9000 5 Jaguar 6000 Merged dataframe with left outer join... Car Units Reg_Price 0 BMW 100 7000.0 1 Lexus 150 1500.0 2 Audi 110 NaN 3 Mustang 80 8000.0 4 Bentley 110 NaN 5 Jaguar 90 6000.0