import pandas as pd

def merge_columns_and_export(df1, df2, col_name, file_name):
    """
    Merge two columns in the same position of each dataframe and export to .csv
    :param df1: dataframe 1
    :param df2: dataframe 2
    :param col_name: column name to merge
    :param file_name: output file name
    :return: None
    """
    # find matches
    matches = pd.merge(df1, df2, how='inner', on=col_name)

    # merge columns
    merged = pd.concat([matches[col_name], matches.iloc[:,1:len(matches.columns)]], axis=1)

    # export to csv
    merged.to_csv(file_name, index=False)

# example usage
df1 = pd.read_csv('dataset1.csv')
df2 = pd.read_csv('dataset2.csv')
merge_columns_and_export(df1, df2, 'id', 'merged.csv')

此函数首先查找两个数据帧中给定列名匹配的行，然后将每个匹配的行的两个数据帧中相同位置的两个列合并为一列。最后将结果导出到一个 .csv 文件中。在此示例中，我们使用 pd.read_csv 从文件读取数据，处理后将结果导出到 merged.csv。