You can use the merge function in pandas to merge two dataframes based on columns df1['A'] and df2['B']. Here's an example code snippet:

```python
merged_df = pd.merge(df1, df2, left_on='A', right_on='B')
```

This will merge two dataframes based on columns df1['A'] and df2['B'] and create a new dataframe called merged_df.

I hope this helps! Let me know if you have any other questions.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence