10、条件控制语句

分支选择结构

if 2 > 1:
    print('2 > 1 is true')
else:
    print('2 > 1 is false')

if 1 == 1:
    print('1 == 1 is true')

多分支选择结构

color = input()
if color == 'red':
    print('color is red')
elif color == 'green':
    print('color is green')
elif color == 'blue':
    print('color is ')
else:
    print('color is other')

分支嵌套结构

sex = input()
age = int(input())
if sex == 'male':
    if age > 50:
        print('old male')
    else:
        print('young male')
else:
    if age > 50:
        print('old female')
    else:
        print('young female')

参考资料

http://www.imooc.com/wiki/pythonlesson1/pythonifelse.html