dict数据结构在保存为csv数据类型时，如何克服ValueError: arrays must all be same length异常？已解决

import pandas as pd

a={'a1':[1,2,3,4],'a2':[2,3],'a3':[3,4,5,6,7,8,9]}

print(pd.Dataframe.from_dict(a,orient='index').T)

这里我添加了**.T**转置，可以将键值对的键作为列名；
输出：

    a1   a2   a3
0  1.0  2.0  3.0
1  2.0  3.0  4.0
2  3.0  NaN  5.0
3  4.0  NaN  6.0
4  NaN  NaN  7.0
5  NaN  NaN  8.0
6  NaN  NaN  9.0