将CSV导入SQLite3时遇TypeError：空字符串为Tasks无效关键字参数

将CSV文件导入SQLite3数据库时触发错误：TypeError: '' is an invalid keyword argument for Tasks。使用Python的ORM库SQLAlchemy，通过declarative_base()定义了Tasks映射类，尝试将csv.DictReader读取的行数据转换为Tasks实例时出现该问题，相关代码及报错堆栈如下：

import csv

from dateutil.parser import parse
from sqlalchemy import Column, Date, Float, Integer, String, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker


engine = create_engine("sqlite:///tasks.sqlite3", echo=True)

Base = declarative_base()


""" Now we will define the user class """
class Tasks(Base):
    """ Table arguments other than the name, metadata, and mapped Column arguments are specified using the __table_args__ class attribute. The __table_args__ class attribute in this case will be assigned a string value.  
    
    https://docs.sqlalchemy.org/en/13/orm/extensions/declarative/table_config.html """
    # Tasks_ID, Description, User_ID

    __tablename__ = "tasks"      # This is User class database table name attribute

    # task_id
    Tasks_ID = Column(Integer, primary_key = True)        # This the primary key attribute

    # description
    Description = Column(String(30))

    # User_ID
    User_ID = Column(Integer)

    # Sprint_ID
    Sprint_ID = Column(Integer)

    # Team_ID
    Team_ID = Column(Integer)

    # Story_Points
    Story_Points = Column(Integer, nullable=True)

    Current_State = Column(String(30))


    # Sprint_ID , Team_ID, Story_Points, Current_State 


Base.metadata.create_all(engine)

Session = sessionmaker(bind=engine)


def parse_none(dt):
    """Trys to parse a string date and returns None if unable to."""
    try:
        return parse(dt)
    except:
        return None


def prepare_listing(row):
    """Takes a row from CSV file and returns a Listing object from it."""

    row["Story_Points"] = parse_none(row["Story_Points"])
    return Tasks(**row)


with open("new_tasks.csv", encoding="utf-8", newline="") as csv_file:
    csvreader = csv.DictReader(csv_file, quotechar='"')

    listings = [prepare_listing(row) for row in csvreader]

    session = Session()
    session.add_all(listings)
    session.commit()

报错堆栈：

TypeError                                 Traceback (most recent call last)
/Users/shawnyang/Downloads/test/test2.ipynb Cell 1 in <cell line: 85>()
     85 with open("new_tasks.csv", encoding="utf-8", newline="") as csv_file:
     86     csvreader = csv.DictReader(csv_file, quotechar='"')
---> 88     listings = [prepare_listing(row) for row in csvreader]
     90     session = Session()
     91     session.add_all(listings)

/Users/shawnyang/Downloads/test/test2.ipynb Cell 1 in <listcomp>(.0)
     85 with open("new_tasks.csv", encoding="utf-8", newline="") as csv_file:
     86     csvreader = csv.DictReader(csv_file, quotechar='"')
---> 88     listings = [prepare_listing(row) for row in csvreader]
     90     session = Session()
     91     session.add_all(listings)

/Users/shawnyang/Downloads/test/test2.ipynb Cell 1 in prepare_listing(row)
     78 """Takes a row from CSV file and returns a Listing object from it."""
     80 row["Story_Points"] = parse_none(row["Story_Points"])
---> 81 return Tasks(**row)

File <string>:4, in __init__(self, **kwargs)

File /Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/sqlalchemy/orm/state.py:481, in InstanceState._initialize_instance(*mixed, **kwargs)
    479     return manager.original_init(*mixed[1:], **kwargs)
...
   1164             "%r is an invalid keyword argument for %s" % (k, cls_.__name__)
   1165         )
   1166     setattr(self, k, kwargs[k])

TypeError: '' is an invalid keyword argument for Tasks

解决方案 #

错误根源 #

报错提示空字符串''是Tasks类的无效参数，说明CSV文件的表头存在空列名，或者csv.DictReader解析时生成了空字符串作为键名，而Tasks类没有对应的属性，实例化时就会触发错误。

修复步骤 #

1. 清理CSV表头
   打开new_tasks.csv文件，检查第一行表头，删除其中的空列名，确保所有表头和Tasks类的属性名完全匹配（注意大小写，比如Tasks_ID、Description等）。

2. 在代码中过滤无效键
   如果无法修改CSV文件，可在prepare_listing函数中过滤掉行数据里的空键和Tasks类未定义的键：

   def prepare_listing(row):
       """将CSV行数据转换为Tasks实例"""
       # 定义Tasks类的有效属性集合
       valid_attrs = {'Tasks_ID', 'Description', 'User_ID', 'Sprint_ID', 'Team_ID', 'Story_Points', 'Current_State'}
       # 过滤掉空键和无效键
       cleaned_row = {k: v for k, v in row.items() if k in valid_attrs and k.strip() != ''}
       # 处理Story_Points字段
       if 'Story_Points' in cleaned_row:
           cleaned_row["Story_Points"] = parse_none(cleaned_row["Story_Points"])
       return Tasks(**cleaned_row)
   

3. 修正parse_none函数逻辑
   原函数用dateutil.parser.parse处理Story_Points（整数类型）是错误的，应该改为转换整数的逻辑：

   def parse_none(value):
       """尝试将字符串转为整数，失败则返回None"""
       try:
           return int(value.strip()) if value.strip() else None
       except (ValueError, TypeError):
           return None
   

内容的提问来源于stack exchange，提问作者Born2Student