控制流

# 条件语句
if x > 0:
    print("正数")
elif x < 0:
    print("负数")
else:
    print("零")

# for 循环
for i in range(5):      # 0, 1, 2, 3, 4
    print(i)

for item in [1, 2, 3]:  # 遍历列表
    print(item)

# while 循环
while condition:
    # do something
    if should_stop:
        break       # 跳出循环
    if should_skip:
        continue    # 跳过本次