Python怎么用?从基础到进阶的完整指南

python怎么用 Python是一种通用编程语言,应用范围广泛。以下从基础使用到进阶应用分层次说明: 环境配置 - 下载安装Python解释器(官网pyth...

python怎么用

Python是一种通用编程语言,应用范围广泛。以下从基础使用到进阶应用分层次说明:

  1. 环境配置 - 下载安装Python解释器(官网python.org下载最新稳定版) - 推荐使用PyCharm/VSCode等专业编辑器 - 创建虚拟环境:python -m venv myenv

  2. 基础语法 `python

name = "Alice" # 字符串 age = 25 # 整数 height = 1.75 # 浮点数

if age >= 18:

print("成年人")

else:

print("未成年人")

for i in range(5):

print(i)

`

  1. 核心功能实现
    • 文件操作: `python with open('file.txt', 'r') as f: content = f.read() `
  • 函数定义: `python def greet(name): return f"Hello, {name}!" `
  1. 常用库使用示例
    • 数据处理(pandas): `python import pandas as pd df = pd.read_csv('data.csv') print(df.head()) `
  • 网络请求(requests): `python import requests response = requests.get('https://api.example.com/data') print(response.json()) `
  1. 项目结构建议 my_project/ ├── main.py ├── utils/ │ ├── __init__.py │ └── helpers.py ├── requirements.txt └── README.md

  2. 调试技巧 - 使用pdb调试器: `python import pdb; pdb.set_trace() - 日志记录:python import logging logging.basicConfig(level=logging.DEBUG) `

  3. 性能优化 - 使用列表推导式替代循环 - 合理使用生成器 - 避免全局变量

  4. 虚拟环境管理 `bash

python -m venv venv

venv\Scripts\activate

source venv/bin/activate `

  1. 包管理 `bash

pip install package_name

pip freeze > requirements.txt `

  1. 异常处理 `python try: risky_operation() except ValueError as e: print(f"Error occurred: {e}") finally: cleanup() `

建议从简单脚本开始练习,逐步过渡到完整项目开发。官方文档(docs.python.org)是最权威的学习资源。

Python怎么用进行数据分析?

Python进行数据分析主要通过几个核心库实现完整的工作流程:

  1. 数据获取与加载
    • 使用pandas读取多种数据格式: `python import pandas as pd

df = pd.read_csv('data.csv')

df = pd.read_excel('data.xlsx')

Python怎么用?从基础到进阶的完整指南

import sqlite3 conn = sqlite3.connect('database.db') df = pd.read_sql('SELECT * FROM table', conn) `

  1. 数据清洗与预处理
    • 处理缺失值: `python

df.dropna()

df.fillna(value) - 类型转换:python df['column'] = df['column'].astype('float') - 重复值处理:python df.drop_duplicates() `

  1. 数据探索与分析 - 基础统计: `python df.describe() # 统计摘要 df.corr() # 相关系数矩阵 - 分组聚合:python df.groupby('category').agg({'value': ['mean', 'sum']}) - 时间序列处理:python df['date'] = pd.to_datetime(df['date']) df.set_index('date', inplace=True) df.resample('M').mean() # 按月重采样 `

  2. 数据可视化 - 使用matplotlib基础绘图: `python import matplotlib.pyplot as plt df['column'].plot(kind='hist') plt.show() - 使用`seaborn`高级可视化:python import seaborn as sns sns.boxplot(x='category', y='value', data=df) - 交互式可视化:python import plotly.express as px px.scatter(df, x='x', y='y', color='category') `

  3. 机器学习分析 - 使用scikit-learn进行建模: `python from sklearn.linear_model import LinearRegression model = LinearRegression() model.fit(X_train, y_train) predictions = model.predict(X_test) `

  4. 完整分析案例流程 `python

data = pd.read_csv('sales.csv')

data = data.dropna() data['date'] = pd.to_datetime(data['date'])

data['month'] = data['date'].dt.month data['day_of_week'] = data['date'].dt.dayofweek

sns.lineplot(x='month', y='revenue', data=data)

from sklearn.ensemble import RandomForestRegressor X = data[['month', 'day_of_week']] y = data['revenue'] model = RandomForestRegressor() model.fit(X, y) `

环境配置建议: - 使用Jupyter Notebook交互式环境 - 通过Anaconda管理包依赖 - 大数据量考虑使用Dask替代pandas

Python怎么用爬取网页数据?

`python

import requests from bs4 import BeautifulSoup

url = 'https://example.com' headers = {'User-Agent': 'Mozilla/5.0'} response = requests.get(url, headers=headers)

if response.status_code == 200:

soup = BeautifulSoup(response.text, 'html.parser')

for link in soup.find_all('a'):
    print(link.get('href'))


for item in soup.select('.article-title'):
    print(item.text.strip())

else:

print(f"请求失败,状态码:{response.status_code}")

from fake_useragent import UserAgent ua = UserAgent() headers = {'User-Agent': ua.random}

from selenium import webdriver driver = webdriver.Chrome() driver.get(url) dynamic_content = driver.page_source

import time time.sleep(random.uniform(1, 3))

import csv with open('data.csv', 'w', newline='') as f:

writer = csv.writer(f)
writer.writerow(['标题', '链接'])
for item in soup.select('.news-item'):
    writer.writerow([
        item.select_one('.title').text,
        item.select_one('a')['href']
    ])

`

Python怎么用开发网站?

Python开发网站主要涉及后端框架的选择、前端交互实现以及部署流程。以下是具体实施步骤:

  1. 后端框架选择与搭建
    • Flask(轻量级方案): `python from flask import Flask app = Flask(name)

@app.route('/') def home():

return "<h1>Hello World</h1>"

if name == 'main':

app.run(debug=True)

` 安装方式:pip install flask

  • Django(全功能方案): `bash django-admin startproject mysite cd mysite python manage.py startapp myapp ` 需配置settings.py中的INSTALLED_APPS添加应用
  1. 数据库集成
    • SQLite(开发环境): `python

DATABASES = {

'default': {
    'ENGINE': 'django.db.backends.sqlite3',
    'NAME': BASE_DIR / 'db.sqlite3',
}

} `

  • PostgreSQL(生产环境): `python DATABASES = { 'default': {
      'ENGINE': 'django.db.backends.postgresql',
      'NAME': 'mydatabase',
      'USER': 'dbuser',
      'PASSWORD': 'securepassword',
      'HOST': '127.0.0.1',
      'PORT': '5432',
    

    } } `

  1. 前端模板渲染
    • Django模板示例: `html

      {% extends "base.html" %} {% block content %}

        {% for item in items %}
      • {{ item.name }}
      • {% endfor %}
      {% endblock %} `

  • Flask使用Jinja2: `python @app.route('/users') def users(): return render_template('users.html',
         users=[{'name':'Alice'}, {'name':'Bob'}])
    

    `

  1. REST API开发(DRF示例) `python

from rest_framework import serializers from .models import Product

class ProductSerializer(serializers.ModelSerializer):

class Meta:
    model = Product
    fields = '__all__'

from rest_framework import generics class ProductListCreate(generics.ListCreateAPIView):

queryset = Product.objects.all()
serializer_class = ProductSerializer

`

  1. 部署方案
    • 传统服务器部署: `bash

gunicorn --workers 3 --bind unix:myapp.sock myproject.wsgi:application `

  • Docker部署示例: `dockerfile FROM python:3.9 WORKDIR /app COPY requirements.txt . RUN pip install -r requirements.txt COPY . . CMD ["gunicorn", "--bind", "0.0.0.0:8000", "myproject.wsgi"] `
  1. 现代全栈方案(FastAPI + React) `python

from fastapi import FastAPI from fastapi.middleware.cors import CORSMiddleware

app = FastAPI() app.add_middleware(

CORSMiddleware,
allow_origins=["*"],
allow_methods=["*"]

)

@app.get("/api/items") async def read_items():

return [{"name": "Item 1"}, {"name": "Item 2"}]

`

关键工具链: - 开发工具:PyCharm/VSCode - 版本控制:Git + GitHub - 测试框架:pytest - 环境管理:pipenv/poetry - 异步支持:ASGI服务器(Uvicorn/Hypercorn) - 监控:Sentry + Prometheus

猜你感兴趣:
上一篇
下一篇