Python中那些简单又好用的特性和用法盘点

x = 5
y = 10
z = 15

if x < y < z:
    print("x is less than y and y is less than z")

total_regions = region_total_instances = total_instances = 0

x = 10
result = "Greater than 10" if x > 10 else "Less than or equal to 10"

def example_function(*args, **kwargs):
    for arg in args:
        # 执行相关操作
    for key, value in kwargs.items():
        # 执行相关操作

my_list = ['apple', 'banana', 'orange']
for index, value in enumerate(my_list):
    print(f"Index: {index}, Value: {value}")

list1 = [1, 2, 3]
list2 = ['a', 'b', 'c']
for item1, item2 in zip(list1, list2):
    print(f"Item from list1: {item1}, Item from list2: {item2}")

import itertools
for item in itertools.chain([1, 2, 3], ['a', 'b', 'c']):
    print(item)

from collections import Counter
my_list = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple']
counter = Counter(my_list)
print(counter)  # 输出为Counter({'apple': 3, 'banana': 2, 'orange': 1})

my_list = [True, False, True, True]
print(any(my_list))  # 输出为True
print(all(my_list))  # 输出为False

my_list = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5]
sorted_list = sorted(my_list)
print(sorted_list)  # 输出为[1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9]

set1 = {1, 2, 3, 4, 5}
set2 = {3, 4, 5, 6, 7}
print(set1.union(set2))  # 输出为{1, 2, 3, 4, 5, 6, 7}
print(set1.intersection(set2))  # 输出为{3, 4, 5}

class CustomContextManager:
    def __enter__(self):
        # 在代码块执行之前执行的操作
        # 可以返回一个值，该值将被赋值给as子句中的变量

    def __exit__(self, exc_type, exc_val, exc_tb):
        # 在代码块执行之后执行的操作
        # 可以处理异常，返回True表示异常被处理，False则会重新抛出异常

# 使用自定义上下文管理器
with CustomContextManager() as obj:
    # 在这里执行一些操作

# 使用生成器表达式计算1到10的平方和
squared_sum = sum(x**2 for x in range(1, 11))
print(squared_sum)

filename = "example.csv"
if filename.endswith((".csv", ".xls", ".xlsx")):
    # 执行相关操作

for item in some_list:
    if condition:
        # 执行相关操作
        break
else:
    # 如果循环自然结束，执行相关操作

# 使用mypy进行静态类型检查
def add_numbers(a: int, b: int) -> int:
    return a + b

result = add_numbers(5, 10)
print(result)