熊猫不向第二个数据帧追加数据

Question

我有两个新旧数据框。我想将新数据框与旧数据框进行比较，当它们的名称和类别匹配时，我想将新数据框的特定值附加到旧数据框，而我的代码将在不附加值的情况下打印结果。这是我的代码

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<div class="x"></div>
<div class="y"></div>

列

 for old in df_old.iterrows():
    for new in df_new.iterrows():
        if (old[1]['Name'] == new[1]['Name']) & (old[1]['Category'] == new[1]['Category']):

            print(old)

            #Code below not working
            old[1]['New Category'] = new[1]['Category']
            old[1]['New Sub Category'] = new[1]['Sub-Category']
            old[1]['New Name'] = new[1]['Name']