44、Python 编程全解析：从基础语句到在线资源

: · Python

raw_input('Press <Enter> when ready')

assert age >= 12, 'Children under the age of 12 are not allowed'

x = 42                   # 简单赋值
name, age = 'Gumby', 60  # 序列解包
x = y = z = 10           # 链式赋值

x *= 2                   # x 翻倍
x += 5                   # x 加 5

try: x.name
except AttributeError: pass
else: print 'Hello', x.name

del x                    # 解除变量绑定
del seq[42]              # 删除序列元素
del seq[42:]             # 删除序列切片
del map['foo']           # 删除映射项

print 'Hello, world!'     # 写入 'Hello, world\n' 到 sys.stdout
print 1, 2, 3             # 写入 '1 2 3\n' 到 sys.stdout
print >> somefile, 'xyz'  # 写入 'xyz' 到 somefile
print 42,                 # 写入 '42 ' 到 sys.stdout

return                   # 从当前函数返回 None
return 42                # 从当前函数返回 42
return 1, 2, 3           # 从当前函数返回 (1, 2, 3)

yield 42                 # 从当前函数返回 42

raise                    # 只能在 except 子句中使用
raise IndexError
raise IndexError, 'index out of bounds'
raise IndexError('index out of bounds')

while True:
    line = file.readline()
    if not line: break
    print line

while True:
    line = file.readline()
    if not line: break
    if line.isspace(): continue
    print line

import math
from math import sqrt
from math import sqrt as squareroot
from math import *

count = 1
def inc():
    global count
    count += 1

exec 'print "Hello, world!"'
exec 'x = 2' in myglobals, mylocals # ... 其中 myglobals 和 mylocals 是字典

if x < 10:
    print 'Less than ten'
elif 10 <= x < 20:
    print 'Less than twenty'
else:
    print 'Twenty or more'

x = 1
while x < 100:
    x *= 2
print x

for i in range(10, 0, -1):
    print i
print 'Ignition!'

try:
    1/0
except ZeroDivisionError:
    print "Can't divide anything by zero."

def double(x):
    return x*2

class Doubler:
    def __init__(self, value):
        self.value = value
    def double(self):
        self.value *= 2

graph LR
    A[项目目标] --> B[准备工作]
    B --> C[首次实现]
    C --> D[进一步探索]
    B --> E[工具准备]

# 示例代码，首次实现部分功能
import pygame

# 初始化 pygame
pygame.init()

# 设置屏幕大小
screen = pygame.display.set_mode((800, 600))

# 游戏主循环
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    pygame.display.flip()

pygame.quit()

graph LR
    A[项目目标] --> B[准备工作]
    B --> C[首次实现]
    C --> D[进一步探索]
    B --> E[工具准备]

# 示例代码，首次实现公告显示功能
import sqlite3

# 连接数据库
conn = sqlite3.connect('bulletin_board.db')
c = conn.cursor()

# 查询公告
c.execute("SELECT * FROM announcements")
announcements = c.fetchall()

# 显示公告
for announcement in announcements:
    print(announcement)

conn.close()

graph LR
    A[项目目标] --> B[准备工作]
    B --> C[首次实现]
    C --> D[进一步探索]
    B --> E[工具准备]

# 示例代码，首次实现新闻获取功能
import requests

# 发送请求获取新闻
response = requests.get('https://newsapi.org/v2/top-headlines?country=us&apiKey=YOUR_API_KEY')
news = response.json()

# 显示新闻标题
for article in news['articles']:
    print(article['title'])

class Person:
    def __init__(self, name, age):
        self.__name = name
        self.__age = age

    def get_name(self):
        return self.__name

    def get_age(self):
        return self.__age

class Student(Person):
    def __init__(self, name, age, student_id):
        super().__init__(name, age)
        self.student_id = student_id

my_list = [1, 2, 3, 4, 5]
print(my_list[2:4])  # 切片操作

# 生成器示例
def my_generator():
    for i in range(5):
        yield i

gen = my_generator()
for num in gen:
    print(num)

try:
    result = 1 / 0
except ZeroDivisionError:
    print("Can't divide by zero.")

44、Python 编程全解析：从基础语句到在线资源

Python 编程全解析：从基础语句到在线资源

1. Python 语句基础

1.1 简单语句

1.2 其他简单语句

2. 复合语句

3. 函数与类定义

3.1 函数定义

3.2 类定义

4. Python 在线资源

4.1 Python 发行版

4.2 Python 文档

4.3 有用的工具包和模块

4.4 新闻组和邮件列表

5. Python 符号与变量索引

5.1 符号索引

5.2 变量与方法索引

6. Python 项目实践

6.1 街机游戏项目

6.2 公告板项目

6.3 新闻项目

7. Python 编程要点总结

7.1 编程概念要点

7.2 编程技巧要点

7.3 资源利用要点