DataFrame.loc multiple columns replace 
Python 3.6.8
pandas==0.25.3

```python
#! -*- coding:utf-8 -*-
import pandas as pd
df = pd.DataFrame([
    {'a':'a1','b':'b1','c':'c1','d':'d1','e':'e1'},
    {'a':'a2','b':'b2','c':'c2','d':'d2','e':'e2'}
    ])
import copy
df2 = copy.deepcopy(df)

 

print(df)
#     a   b   c   d   e
# 0  a1  b1  c1  d1  e1
# 1  a2  b2  c2  d2  e2


df.loc[df['a']=='a2', ['c']] = df['e']
print(df)
#     a   b   c   d   e
# 0  a1  b1  c1  d1  e1
# 1  a2  b2  e2  d2  e2

# loc muti columns replace has some problem
df.loc[df['a']=='a2', ['b','c']] = df[['d','e']]
print(df)
#     a    b    c   d   e
# 0  a1   b1   c1  d1  e1
# 1  a2  NaN  NaN  d2  e2
```