流程控制 #

条件控制 #

if #

if x > y:
    print('x > y')
    print('end')
elif x < y:
    print('x < y')
else:
    print('x == y')
print('end')

循环控制 #

For #

For 语句

nums = [1, 2, 3, 4, 5]
for n in nums:
    print('for-in', str(n))

也可以通过 Range 对象实现基于索引的循环，左开右闭

for n in range(1, 10, 3):
    print('for-range', str(n))  # 1 4 7

For 推导式

a = [i for i in range(100) if not (i % 2) and i % 3]
print(a)  # [2, 4, 8, 10, 14,...

b = {i: i % 2 == 0 for i in range(10)}
print(b)  # {0: True, 1: False, 2: True, 3: False, 4: True,...

While #

Python 的 while 语句可以附带 else

i = 0
while i < 3:
    print('while', str(i))
    i += 1
else:
    print('end while', str(i))

Break 和 Pass #

Break 用于终止循环，Pass 用于进入下次循环

Break

for i in range(1, 5):
    if i == 3:
        break
    print('break', str(i))

Pass

for i in range(1, 5):
    if i == 3:
        pass
    print('next', str(i))