在 Python 函数中调用字符串时出现“TypeError: must be str, not NoneType”错误

如何解决在 Python 函数中调用字符串时出现“TypeError: must be str, not NoneType”错误

这是一个将作业状态写入 MySQL 进程日志的函数：

driver.find_element_by_css_selector("div.flex.flex-column")

我收到错误：

# job status function        
def mysql_write_jobstatus(host,user,password,batch_id,source,status,job_start_dt,job_finish_dt = None,filename = None,error = None):
    if job_finish_dt is None:
        status_sql = "INSERT INTO schema.table (\
        batch_id,run_date,data_processed,job_start_dt)\
        values ('" + batch_id + "','" + rundate + "','" + source + "','" + status + "','" + data_processed + \
                "','" + job_start_dt + "');"
    else:
        status_sql = "UPDATE schema.table SET status = '" + status + "',\
        job_finish_dt = '" + job_finish_dt + "',filename = '" + filename + "',error = '" + error + "' WHERE batch_id = '" + batch_id + "' AND \
        source = '" + source + "';"
    try:
        con = pymysql.connect(host=lol,user=lol,password=lol,autocommit=True,local_infile=1)
        print('Connected to DB: {}'.format(host))
        # Create cursor and execute Load SQL
        cursor = con.cursor()
        cursor.execute(status_sql)
        con.close()
        
    except Exception as e:
        print('Error: {}'.format(str(e)))
        sys.exit(1)

source 是一个字符串变量，它只在代码顶部定义一次，如下所示：

  File "<ipython-input-222-0d62a2bb45ad>",line 75,in mysql_write_jobstatus
    source = '" + source +"';"

TypeError: must be str,not NoneType

我所看到的一切都让我相信这是一个字符串。同一个 SQL 调用中的其他被调用变量按预期工作。

我已从全局环境中删除了所有变量。

有什么想法吗？

easygui.msgbox ('You entered ' + flavour) TypeError: must be str,not NoneType 没有帮助，因为 source 是一个手动定义的字符串，永远不应更改为 NoneType。