python must memorize entry code

Python is a simple and easy-to-learn programming language, suitable for beginners to get started. The following are some necessary Python entry codes to help you get started programming quickly:

1. Output Hello World

print("Hello World!")

2. Variables and data types

# 定义变量并赋值
name = "Alice"
age = 18
height = 1.65
is_student = True
# 打印变量
print(name)
print(age)
print(height)
print(is_student)
# 数据类型转换
age_str = str(age)
height_int = int(height)
is_student_str = str(is_student)

3. Input

# 输入字符串
name = input("请输入您的姓名：")
print("您的姓名是：", name)
# 输入数字
age = int(input("请输入您的年龄："))
print("您的年龄是：", age)

4. Conditional judgment

age = int(input("请输入您的年龄："))
if age >= 18:
print("您已经成年了!")
else:
print("您还未成年!")

5. Loop

# while循环
count = 0
while count < 5:
print("当前计数：", count)
count += 1
# for循环
for i in range(5):
print("当前计数：", i)

6. Lists and dictionaries

# 列表
fruits = ['apple', 'banana', 'orange']
print(fruits[0]) # 输出apple
fruits.append('grape') # 添加元素
print(fruits) # 输出['apple', 'banana', 'orange', 'grape']
# 字典
person = {'name': 'Alice', 'age': 18, 'gender': 'female'}
print(person['name']) # 输出Alice
person['height'] = 1.65 # 添加键值对
print(person) # 输出{'name': 'Alice', 'age': 18, 'gender': 'female', 'height': 
1.65}

7. Functions

# 定义函数
def greet(name):
print("Hello,", name)
# 调用函数
greet("Alice")

8.Exception handling

try:
num = int(input("请输入一个数字："))
result = 10 / num
print("结果：", result)
except ZeroDivisionError:
print("除数不能为0!")
except ValueError:
print("请输入一个有效的数字!")

The above are some examples of Python entry code, I hope it can help you start learning Python programming. If you have any questions, please feel free to ask.

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