Python 基于键值对填充序列

我有一个数据框，其中包括一个代码和名称字典。有些名字是空白的。我试图根据代码与名称匹配的其他示例来填补这些空白。到目前为止，我已经按代码将df分类，但不知道如何“填空”。这是我的密码：

import pandas as pd
import json
from pandas.io.json import json_normalize
df = pd.read_json('data/world_bank_projects.json')
theme= pd.DataFrame([val for pair in df['mjtheme_namecode'].values for val in pair])
theme1 = theme.set_index('code').sort_index()
print(theme1)

                     name
code                     
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1     Economic management
1                        
1     Economic management
1                        
1     Economic management
1     Economic management
1                        
1     Economic management
1     Economic management
1     Economic management
1     Economic management

在我填写完之后，我想数一数（无论是代码还是名字，应该是相同的）。我想我可以用价值计量，对吗