Python break的高级用法，终止多重循环，无条件退出循环(图文详解1)

# 终止多重循环
for i in range(3):
    print(f"Outer loop: {i}")
    for j in range(5):
        print(f"  Inner loop: {j}")
        if j == 3:
            break
    else:
        continue
    print("This will be printed")

# 无条件退出循环
count = 0
while True:
    print(count)
    count += 1
    if count > 5:
        break

# break 语句与函数返回
def find_number(numbers, target):
    for num in numbers:
        if num == target:
            print(f"Found {target}")
            return num
    print(f"{target} not found")
    return None

result = find_number([1, 2, 3, 4, 5], 3)
print(result)  # 输出: Found 3, 3
result = find_number([1, 2, 3, 4, 5], 6)
print(result)  # 输出: 6 not found, None

# break 语句与上下文管理器
with open("file.txt", "r") as f:
    for line in f:
        if "error" in line:
            print(f"Error found: {line.strip()}")
            break
    else:
        print("No errors found")