Pandas对多列进行升降序排列
df = pd.DataFrame(rows, columns = ["llx", "lly", "urx", "ury", "text", "page"])
df.sort_values(['lly','llx'], ascending=[False,True])
df = pd.DataFrame(rows, columns = ["llx", "lly", "urx", "ury", "text", "page"])
df.sort_values(['lly','llx'], ascending=[False,True])
