python将json对象映射为集合，因此对json文件的追加写入，就直接变为对集合的更新操作。

import json
#导入json包

data={}
#创建一个data集合用于接收并暂存数据

json_list=["cls_FinancialClassification_answer.json",\
           "cls_MedicalClassification_answer.json",\
           "intent_InsuranceIntentChange_answer.json",\
           "intent_InsuranceIntentConsult_answer.json",\
           "intent_InsuranceIntentSearch_answer.json",\
           "nli_FinancialNLI_answer.json",\
           "nli_MedicalNLI_answer.json",\
           "senti_FinancialSentiment_answer.json",\
           "sts_FinancialSimilarity_answer.json",\
           "sts_MedicalSimilarity_answer.json"
           ]
#需要追加的json文件列表

此处需要提前创建并声明data的数据类型为集合，以保证之后更新操作的正确性。

遍历需要追加写入的json_list,并逐个更新到data集合中。

此处需要强调，如果json文件中有中文，需要 encoding='utf-8'

for json_file in json_list:    
    with open(json_file,encoding='utf-8') as f:
        data.update(json.load(f))

使用json.dump方法将data集合输出为json文件。

#输出answer.json文件
with open('answer.json','w',encoding='utf-8') as w_f:
    json.dump(data,w_f,ensure_ascii=False,indent=2)

完整代码：

import json

data={}

json_list=["cls_FinancialClassification_answer.json",\
           "cls_MedicalClassification_answer.json",\
           "intent_InsuranceIntentChange_answer.json",\
           "intent_InsuranceIntentConsult_answer.json",\
           "intent_InsuranceIntentSearch_answer.json",\
           "nli_FinancialNLI_answer.json",\
           "nli_MedicalNLI_answer.json",\
           "senti_FinancialSentiment_answer.json",\
           "sts_FinancialSimilarity_answer.json",\
           "sts_MedicalSimilarity_answer.json"
           ]

for json_file in json_list:    
    with open(json_file,encoding='utf-8') as f:
        data.update(json.load(f))


#输出answer.json文件
with open('answer.json','w',encoding='utf-8') as w_f:
    json.dump(data,w_f,ensure_ascii=False,indent=2)