pyhotn3入门基础-５条件判断与循环

条件判断

if <条件判断1>:
    <执行1>
elif <条件判断2>:
    <执行2>
elif <条件判断3>:
    <执行3>
else:
    <执行4>

age = 20
if age >= 6:
    print('teenager')
elif age >= 18:
    print('adult')
else:
    print('kid')

#x非0
if x:
    print('xx')             

input() 输入string 转化为int  用方法int(str0

s = input('birth: ')
birth = int(s)
if birth < 2000:
    print('00前')
else:
    print('00后')

循环
1.  列表循环  for x in xs:

names = ['Michael', 'Bob', 'Tracy']
for name in names:
    print(name)

sum = 0
for x in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]:
    sum = sum + x
print(sum)

2. range() 函数生成整数序列，可以通过list()函数再转换为list

>>> list(range(5))
[0, 1, 2, 3, 4]

sum = 0
for x in range(101):
    sum = sum + x
print(sum)

3.  while 循环

sum = 0
n = 99
while n > 0:
    sum = sum + n
    n = n - 2
print(sum)

4. break

n = 1
while n <= 100:
    if n > 10: # 当n = 11时，条件满足，执行break语句
        break # break语句会结束当前循环
    print(n)
    n = n + 1
print('END')

5. continue

n = 0
while n < 10:
    n = n + 1
    if n % 2 == 0: # 如果n是偶数，执行continue语句
        continue # continue语句会直接继续下一轮循环，后续的print()语句不会执行
    print(n)

终端运行死循环的时候 Ctrl+C 可以强制结束Python进程