{"id":1011334,"date":"2024-12-27T11:29:03","date_gmt":"2024-12-27T03:29:03","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1011334.html"},"modified":"2024-12-27T11:29:06","modified_gmt":"2024-12-27T03:29:06","slug":"python%e5%a6%82%e4%bd%95%e5%86%99update","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1011334.html","title":{"rendered":"python\u5982\u4f55\u5199update"},"content":{"rendered":"

\"python\u5982\u4f55\u5199update\"<\/p>\n

\u5728Python\u4e2d\uff0c\u66f4\u65b0\u6570\u636e\u901a\u5e38\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u6570\u636e\u5e93\u64cd\u4f5c\u5e93\u6216\u76f4\u63a5\u64cd\u4f5c\u6570\u636e\u7ed3\u6784\uff08\u5982\u5b57\u5178\u548c\u5217\u8868\uff09\u6765\u5b9e\u73b0\u3002\u5e38\u89c1\u7684\u65b9\u6cd5\u5305\u62ec\u4f7f\u7528SQLAlchemy\u6216Peewee\u7b49ORM\u5e93\u8fdb\u884c\u6570\u636e\u5e93\u66f4\u65b0\u64cd\u4f5c\u3001\u4f7f\u7528pandas\u8fdb\u884c\u6570\u636e\u5206\u6790\u548c\u66f4\u65b0\u3001\u4f7f\u7528\u5185\u7f6e\u7684\u6570\u636e\u7ed3\u6784\u66f4\u65b0\u65b9\u6cd5\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u8fd9\u4e9b\u65b9\u6cd5\u7684\u5177\u4f53\u5b9e\u73b0\u548c\u4f7f\u7528\u573a\u666f\uff0c\u91cd\u70b9\u4ecb\u7ecd\u5982\u4f55\u4f7f\u7528SQLAlchemy\u66f4\u65b0\u6570\u636e\u5e93\u3002<\/strong><\/p>\n<\/p>\n

\u4e00\u3001SQLALCHEMY \u66f4\u65b0\u6570\u636e\u5e93<\/p>\n<\/p>\n

SQLAlchemy\u662f\u4e00\u4e2aPython SQL\u5de5\u5177\u5305\u548cORM\u6846\u67b6\uff0c\u63d0\u4f9b\u4e86\u4e00\u79cd\u7b80\u6d01\u7684\u65b9\u5f0f\u6765\u4e0e\u6570\u636e\u5e93\u8fdb\u884c\u4ea4\u4e92\u3002\u4ee5\u4e0b\u662f\u5982\u4f55\u4f7f\u7528SQLAlchemy\u66f4\u65b0\u6570\u636e\u5e93\u4e2d\u7684\u8bb0\u5f55\u3002<\/p>\n<\/p>\n

1.1 \u5b89\u88c5\u548c\u8bbe\u7f6eSQLAlchemy<\/h3>\n<\/p>\n

\u5728\u5f00\u59cb\u4e4b\u524d\uff0c\u8bf7\u786e\u4fdd\u5df2\u5b89\u88c5SQLAlchemy\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u8fdb\u884c\u5b89\u88c5\uff1a<\/p>\n<\/p>\n

pip install sqlalchemy<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u63a5\u4e0b\u6765\uff0c\u8bbe\u7f6e\u4e00\u4e2a\u7b80\u5355\u7684\u6570\u636e\u5e93\u8fde\u63a5\u548c\u6a21\u578b\uff1a<\/p>\n<\/p>\n
from sqlalchemy import create_engine, Column, Integer, String, Sequence<\/p>\n
from sqlalchemy.ext.declarative import declarative_base<\/p>\n
from sqlalchemy.orm import sessionmaker<\/p>\n
engine = create_engine('sqlite:\/\/\/:memory:', echo=True)<\/p>\n
Base = declarative_base()<\/p>\n
class User(Base):<\/p>\n
    __tablename__ = 'users'<\/p>\n
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)<\/p>\n
    name = Column(String(50))<\/p>\n
    age = Column(Integer)<\/p>\n
Base.metadata.create_all(engine)<\/p>\n
Session = sessionmaker(bind=engine)<\/p>\n
session = Session()<\/p>\n
<\/code><\/pre>\n<\/p>\n
1.2 \u63d2\u5165\u548c\u66f4\u65b0\u8bb0\u5f55<\/h3>\n<\/p>\n
\u9996\u5148\uff0c\u63d2\u5165\u4e00\u6761\u8bb0\u5f55\u5230\u6570\u636e\u5e93\uff1a<\/p>\n<\/p>\n
new_user = User(name='Alice', age=30)<\/p>\n
session.add(new_user)<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u63a5\u7740\uff0c\u901a\u8fc7\u67e5\u8be2\u627e\u5230\u8be5\u8bb0\u5f55\u5e76\u8fdb\u884c\u66f4\u65b0\uff1a<\/p>\n<\/p>\n
user = session.query(User).filter_by(name='Alice').first()<\/p>\n
user.age = 31<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u901a\u8fc7ORM\u7684\u67e5\u8be2\u548c\u66f4\u65b0\u65b9\u6cd5\uff0c\u80fd\u591f\u8f7b\u677e\u5730\u8fdb\u884c\u6570\u636e\u5e93\u64cd\u4f5c<\/strong>\uff0c\u800c\u4e0d\u9700\u8981\u7f16\u5199\u590d\u6742\u7684SQL\u8bed\u53e5\u3002<\/p>\n<\/p>\n
1.3 \u6279\u91cf\u66f4\u65b0<\/h3>\n<\/p>\n
\u5f53\u9700\u8981\u6279\u91cf\u66f4\u65b0\u8bb0\u5f55\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2a\u66f4\u9ad8\u6548\u7684\u65b9\u6cd5\uff1a<\/p>\n<\/p>\n
session.query(User).filter(User.age < 30).update({"age": User.age + 1})<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u79cd\u65b9\u6cd5\u5229\u7528\u4e86\u6570\u636e\u5e93\u7684\u539f\u751f\u66f4\u65b0\u529f\u80fd\uff0c\u80fd\u591f\u5728\u4e0d\u52a0\u8f7d\u6240\u6709\u8bb0\u5f55\u7684\u60c5\u51b5\u4e0b\u76f4\u63a5\u8fdb\u884c\u66f4\u65b0\u3002<\/p>\n<\/p>\n
\u4e8c\u3001PANDAS \u6570\u636e\u66f4\u65b0<\/p>\n<\/p>\n
Pandas\u662f\u4e00\u4e2a\u5f3a\u5927\u7684\u6570\u636e\u5206\u6790\u5e93\uff0c\u5e38\u7528\u4e8e\u5904\u7406\u7ed3\u6784\u5316\u6570\u636e\u3002\u5b83\u63d0\u4f9b\u4e86\u7b80\u5355\u7684\u65b9\u6cd5\u6765\u66f4\u65b0\u6570\u636e\u5e27\u4e2d\u7684\u6570\u636e\u3002<\/p>\n<\/p>\n
2.1 \u66f4\u65b0\u6570\u636e\u5e27\u4e2d\u7684\u5217<\/h3>\n<\/p>\n
\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u6570\u636e\u5e27\uff1a<\/p>\n<\/p>\n
import pandas as pd<\/p>\n
data = {'Name': ['Alice', 'Bob', 'Charlie'],<\/p>\n
        'Age': [25, 30, 35]}<\/p>\n
df = pd.DataFrame(data)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u65b9\u6cd5\u66f4\u65b0\u6570\u636e\u5e27\u4e2d\u7684\u5217\uff1a<\/p>\n<\/p>\n
df.loc[df['Name'] == 'Alice', 'Age'] = 31<\/p>\n
<\/code><\/pre>\n<\/p>\n
2.2 \u6761\u4ef6\u66f4\u65b0<\/h3>\n<\/p>\n
Pandas\u5141\u8bb8\u6839\u636e\u6761\u4ef6\u66f4\u65b0\u6570\u636e\u5e27\u4e2d\u7684\u6570\u636e\uff1a<\/p>\n<\/p>\n
df.loc[df['Age'] > 30, 'Age'] -= 1<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u79cd\u65b9\u6cd5\u975e\u5e38\u9002\u5408\u5904\u7406\u5927\u89c4\u6a21\u6570\u636e\u66f4\u65b0\uff0c\u56e0\u5176\u5177\u6709\u826f\u597d\u7684\u6027\u80fd\u548c\u7b80\u6d01\u7684\u8bed\u6cd5\u3002<\/p>\n<\/p>\n
\u4e09\u3001PYTHON \u5185\u7f6e\u6570\u636e\u7ed3\u6784\u66f4\u65b0<\/p>\n<\/p>\n
Python\u5185\u7f6e\u7684\u6570\u636e\u7ed3\u6784\uff08\u5982\u5b57\u5178\u548c\u5217\u8868\uff09\u4e5f\u63d0\u4f9b\u4e86\u66f4\u65b0\u6570\u636e\u7684\u65b9\u6cd5\u3002<\/p>\n<\/p>\n
3.1 \u5b57\u5178\u66f4\u65b0<\/h3>\n<\/p>\n
\u5b57\u5178\u662fPython\u4e2d\u5e38\u7528\u7684\u6570\u636e\u7ed3\u6784\uff0c\u4ee5\u4e0b\u662f\u5982\u4f55\u66f4\u65b0\u5b57\u5178\u4e2d\u7684\u503c\uff1a<\/p>\n<\/p>\n
data = {'name': 'Alice', 'age': 25}<\/p>\n
data['age'] = 26  # \u76f4\u63a5\u66f4\u65b0\u5b57\u5178\u4e2d\u7684\u503c<\/p>\n
<\/code><\/pre>\n<\/p>\n
3.2 \u5217\u8868\u66f4\u65b0<\/h3>\n<\/p>\n
\u5217\u8868\u662fPython\u4e2d\u53e6\u4e00\u79cd\u91cd\u8981\u7684\u6570\u636e\u7ed3\u6784\uff0c\u53ef\u4ee5\u901a\u8fc7\u7d22\u5f15\u66f4\u65b0\u5143\u7d20\uff1a<\/p>\n<\/p>\n
numbers = [1, 2, 3, 4, 5]<\/p>\n
numbers[2] = 10  # \u66f4\u65b0\u5217\u8868\u4e2d\u7d22\u5f15\u4e3a2\u7684\u5143\u7d20<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001PEEWEE \u66f4\u65b0\u6570\u636e\u5e93<\/p>\n<\/p>\n
Peewee\u662f\u53e6\u4e00\u4e2aPython ORM\u5e93\uff0c\u5177\u6709\u8f7b\u91cf\u7ea7\u548c\u7b80\u5355\u7684\u7279\u70b9\u3002\u4ee5\u4e0b\u662f\u5982\u4f55\u4f7f\u7528Peewee\u8fdb\u884c\u66f4\u65b0\u64cd\u4f5c\u3002<\/p>\n<\/p>\n
4.1 \u8bbe\u7f6e\u548c\u63d2\u5165\u6570\u636e<\/h3>\n<\/p>\n
\u9996\u5148\uff0c\u8bbe\u7f6e\u4e00\u4e2a\u6570\u636e\u5e93\u548c\u6a21\u578b\uff1a<\/p>\n<\/p>\n
from peewee import *<\/p>\n
db = SqliteDatabase(':memory:')<\/p>\n
class User(Model):<\/p>\n
    name = CharField()<\/p>\n
    age = IntegerField()<\/p>\n
    class Meta:<\/p>\n
        database = db<\/p>\n
db.connect()<\/p>\n
db.create_tables([User])<\/p>\n
\u63d2\u5165\u6570\u636e<\/strong><\/h2>\n
user = User.create(name='Alice', age=30)<\/p>\n
<\/code><\/pre>\n<\/p>\n
4.2 \u66f4\u65b0\u6570\u636e<\/h3>\n<\/p>\n
\u4f7f\u7528Peewee\u66f4\u65b0\u6570\u636e\u5e93\u4e2d\u7684\u8bb0\u5f55\uff1a<\/p>\n<\/p>\n
query = User.update(age=31).where(User.name == 'Alice')<\/p>\n
query.execute()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u79cd\u65b9\u6cd5\u76f4\u63a5\u4f7f\u7528\u4e86Peewee\u7684\u67e5\u8be2\u6784\u9020\u5668\uff0c\u80fd\u591f\u4ee5\u4e00\u79cd\u58f0\u660e\u5f0f\u7684\u65b9\u5f0f\u66f4\u65b0\u6570\u636e<\/strong>\u3002<\/p>\n<\/p>\n
\u4e94\u3001\u603b\u7ed3<\/p>\n<\/p>\n
\u5728Python\u4e2d\uff0c\u66f4\u65b0\u6570\u636e\u53ef\u4ee5\u901a\u8fc7\u591a\u79cd\u65b9\u5f0f\u5b9e\u73b0\uff0c\u5177\u4f53\u65b9\u6cd5\u7684\u9009\u62e9\u53d6\u51b3\u4e8e\u4f7f\u7528\u7684\u573a\u666f\u548c\u6570\u636e\u7c7b\u578b\u3002\u5bf9\u4e8e\u6570\u636e\u5e93\u64cd\u4f5c\uff0cSQLAlchemy\u548cPeewee\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684ORM\u529f\u80fd\uff0c\u80fd\u591f\u7b80\u5316\u6570\u636e\u5e93\u64cd\u4f5c\u7684\u590d\u6742\u6027\u3002\u5bf9\u4e8e\u6570\u636e\u5206\u6790\uff0cPandas\u63d0\u4f9b\u4e86\u7075\u6d3b\u7684\u6570\u636e\u5e27\u64cd\u4f5c\u80fd\u529b\u3002\u800c\u5bf9\u4e8e\u7b80\u5355\u7684\u6570\u636e\u64cd\u4f5c\uff0cPython\u5185\u7f6e\u7684\u6570\u636e\u7ed3\u6784\u65b9\u6cd5\u5df2\u7ecf\u8db3\u591f\u5f3a\u5927\u3002\u4e86\u89e3\u548c\u638c\u63e1\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u80fd\u591f\u8ba9\u4f60\u5728\u6570\u636e\u5904\u7406\u548c\u64cd\u4f5c\u4e2d\u6e38\u5203\u6709\u4f59\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
 Python\u4e2d\u5982\u4f55\u5b9e\u73b0\u6570\u636e\u66f4\u65b0\u64cd\u4f5c\uff1f<\/strong>
\u5728Python\u4e2d\uff0c\u6570\u636e\u66f4\u65b0\u901a\u5e38\u901a\u8fc7\u6570\u636e\u5e93\u64cd\u4f5c\u6216\u6570\u636e\u7ed3\u6784\u7684\u4fee\u6539\u6765\u5b9e\u73b0\u3002\u5982\u679c\u4f7f\u7528SQLite\u6216\u5176\u4ed6\u6570\u636e\u5e93\uff0c\u53ef\u4ee5\u4f7f\u7528UPDATE<\/code> SQL\u8bed\u53e5\u6765\u4fee\u6539\u5df2\u6709\u8bb0\u5f55\u3002\u5bf9\u4e8e\u5b57\u5178\u3001\u5217\u8868\u7b49\u6570\u636e\u7ed3\u6784\uff0c\u53ef\u4ee5\u76f4\u63a5\u5bf9\u5176\u5143\u7d20\u8fdb\u884c\u8d4b\u503c\u4ee5\u5b9e\u73b0\u66f4\u65b0\u3002\u4f8b\u5982\uff0c\u5b57\u5178\u4e2d\u7684\u67d0\u4e2a\u952e\u5bf9\u5e94\u7684\u503c\u53ef\u4ee5\u901a\u8fc7dict[key] = new_value<\/code>\u8fdb\u884c\u66f4\u6539\u3002<\/p>\n
\u5728Python\u4e2d\u5982\u4f55\u4f7f\u7528ORM\u8fdb\u884c\u66f4\u65b0\u64cd\u4f5c\uff1f<\/strong>
\u4f7f\u7528ORM\uff08\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04\uff09\u5e93\uff0c\u5982SQLAlchemy\u6216Django ORM\uff0c\u53ef\u4ee5\u7b80\u5316\u6570\u636e\u5e93\u7684\u66f4\u65b0\u64cd\u4f5c\u3002\u901a\u8fc7\u5b9a\u4e49\u6a21\u578b\u7c7b\uff0c\u53ef\u4ee5\u76f4\u63a5\u5728\u5bf9\u8c61\u4e0a\u8c03\u7528\u65b9\u6cd5\u8fdb\u884c\u66f4\u65b0\u3002\u4f8b\u5982\uff0c\u5728Django\u4e2d\uff0c\u53ef\u4ee5\u901a\u8fc7instance.save()<\/code>\u6765\u4fdd\u5b58\u5bf9\u6a21\u578b\u5b9e\u4f8b\u7684\u4fee\u6539\uff0c\u800c\u5728SQLAlchemy\u4e2d\uff0c\u66f4\u65b0\u540e\u4f7f\u7528session.commit()<\/code>\u6765\u63d0\u4ea4\u66f4\u6539\u3002<\/p>\n
\u5982\u4f55\u5728Python\u4e2d\u5904\u7406\u6587\u4ef6\u5185\u5bb9\u7684\u66f4\u65b0\uff1f<\/strong>
\u5904\u7406\u6587\u4ef6\u5185\u5bb9\u7684\u66f4\u65b0\uff0c\u53ef\u4ee5\u4f7f\u7528Python\u7684\u5185\u7f6e\u6587\u4ef6\u64cd\u4f5c\u529f\u80fd\u3002\u901a\u8fc7\u8bfb\u53d6\u6587\u4ef6\u5185\u5bb9\uff0c\u4fee\u6539\u6240\u9700\u7684\u90e8\u5206\uff0c\u7136\u540e\u5c06\u4fee\u6539\u540e\u7684\u5185\u5bb9\u5199\u56de\u6587\u4ef6\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528with open('filename', 'r+') as file:<\/code>\u6765\u8bfb\u53d6\u6587\u4ef6\u5185\u5bb9\uff0c\u63a5\u7740\u8fdb\u884c\u5fc5\u8981\u7684\u4fee\u6539\uff0c\u6700\u540e\u4f7f\u7528file.write(updated_content)<\/code>\u5c06\u65b0\u7684\u5185\u5bb9\u5199\u5165\u6587\u4ef6\u3002\u4f7f\u7528'r+'<\/code>\u6a21\u5f0f\u53ef\u4ee5\u5728\u8bfb\u53d6\u7684\u540c\u65f6\u8fdb\u884c\u5199\u5165\u64cd\u4f5c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u5728Python\u4e2d\uff0c\u66f4\u65b0\u6570\u636e\u901a\u5e38\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u6570\u636e\u5e93\u64cd\u4f5c\u5e93\u6216\u76f4\u63a5\u64cd\u4f5c\u6570\u636e\u7ed3\u6784\uff08\u5982\u5b57\u5178\u548c\u5217\u8868\uff09\u6765\u5b9e\u73b0\u3002\u5e38\u89c1\u7684\u65b9\u6cd5\u5305\u62ec […]","protected":false},"author":3,"featured_media":1011339,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1011334"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=1011334"}],"version-history":[{"count":"1","href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1011334\/revisions"}],"predecessor-version":[{"id":1011341,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1011334\/revisions\/1011341"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/1011339"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=1011334"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=1011334"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=1011334"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}