Web3.py 入门笔记

Web3.py 学习笔记 📚

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1. Web3.py 简介 🌟

Web3.py 是一个 Python 库，用于与以太坊区块链进行交互。它就像是连接 Python 程序和以太坊网络的桥梁。

官方文档

1.1 主要功能

查询区块链数据（余额、交易等）
发送交易
与智能合约交互
管理以太坊账户

2. 安装和配置 🔧

2.1 安装

# 使用 pip 安装
pip install web3# 或使用 conda 安装
conda install -c conda-forge web3

2.2 基础配置

python">from web3 import Web3# 连接到以太坊网络（这里使用 Infura 提供的节点）
w3 = Web3(Web3.HTTPProvider('https://mainnet.infura.io/v3/YOUR-PROJECT-ID'))# 检查是否连接成功
print(f"是否连接成功: {w3.is_connected()}")

3. 基础操作示例 💡

3.1 查询账户余额

python">def check_eth_balance(address):# 确保地址格式正确if not w3.is_address(address):return "无效的以太坊地址"# 获取余额（单位：Wei）balance_wei = w3.eth.get_balance(address)# 转换为 ETH（1 ETH = 10^18 Wei）balance_eth = w3.from_wei(balance_wei, 'ether')return f"地址余额: {balance_eth} ETH"# 使用示例
address = "0x742d35Cc6634C0532925a3b844Bc454e4438f44e"
print(check_eth_balance(address))

3.2 创建新钱包

python">from eth_account import Account
import secretsdef create_new_wallet():# 生成随机私钥private_key = secrets.token_hex(32)account = Account.from_key(private_key)return {"address": account.address,"private_key": private_key}# 使用示例
wallet = create_new_wallet()
print(f"钱包地址: {wallet['address']}")
print(f"私钥: {wallet['private_key']}")

3.3 查询区块信息

python">def get_block_info(block_number='latest'):# 获取区块信息block = w3.eth.get_block(block_number)info = {"区块号": block.number,"时间戳": block.timestamp,"交易数量": len(block.transactions),"矿工地址": block.miner,"难度": block.difficulty}return info# 使用示例
print(get_block_info())

4. 实用工具函数 🛠️

4.1 单位转换

python"># Wei 转换为 ETH
wei_amount = 1000000000000000000  # 1 ETH
eth_amount = w3.from_wei(wei_amount, 'ether')
print(f"{wei_amount} Wei = {eth_amount} ETH")# ETH 转换为 Wei
eth_amount = 2.5
wei_amount = w3.to_wei(eth_amount, 'ether')
print(f"{eth_amount} ETH = {wei_amount} Wei")

4.2 地址验证

python">def is_valid_address(address):"""验证以太坊地址是否有效"""return w3.is_address(address)# 使用示例
address = "0x742d35Cc6634C0532925a3b844Bc454e4438f44e"
print(f"地址是否有效: {is_valid_address(address)}")

5. 监控交易示例 👀

python">def monitor_transactions(address, num_blocks=10):"""监控指定地址的最近交易"""current_block = w3.eth.block_numberfor block_num in range(current_block - num_blocks, current_block + 1):block = w3.eth.get_block(block_num, full_transactions=True)for tx in block.transactions:if tx['from'].lower() == address.lower() or tx['to'].lower() == address.lower():print(f"\n发现交易:")print(f"交易哈希: {tx['hash'].hex()}")print(f"从: {tx['from']}")print(f"到: {tx['to']}")print(f"数量: {w3.from_wei(tx['value'], 'ether')} ETH")# 使用示例
address = "0x742d35Cc6634C0532925a3b844Bc454e4438f44e"
monitor_transactions(address)