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question:delete the last column of numpy array `a` and assign resulting array to `b`
answer:b = np.delete(a, -1, 1)
question:mmit all the changes after executing a query.
answer:dbb.commit()
question:join two dataframes based on values in selected colum
answer:pd.merge(a, b, on=['A', 'B'], how='outer')
question:et text color as `red` and background color as `#A3C1DA` in qpushbutto
answer:setStyleSheet('QPushButton {background-color: #A3C1DA; color: red;}')