这一次用pandas处理csv文件
comments.csv

import pandas as pd
from snownlp import SnowNLP

df = pd.read_csv("C:\\Users\\zhour\\Documents\\comments.csv")#{'a': [1, 2, 3], 'b': [4, 5, 6], 'c': [7, 8, 9]}是个字典
emotions=[]
for txt in df['sentence']:
    s = SnowNLP(txt)
    emotions.append(s.sentiments)
df.insert(loc=1, column='emotion', value=emotions)  # 在第二列位置插入新列    

df.to_csv("C:\\Users\\zhour\\Documents\\commentsTag.csv",index=False, encoding='gbk')

commentsTag.csv