python --if语句

if语句之后的冒号

以四个空格的缩进来表示隶属关系, Python中不能随意缩进

if  <条件1>:

    statement

elif <条件2>:

    statement

elif <条件3>：

    statement

else:

    statement

i = 1

if i > 0:
    print 'positive i'
    i = i + 1
elif i == 0:
    print 'i is 0'
    i = i * 10
else:
    print 'negative i'
    i = i - 1

print 'new i:',i