_user = "alex"
_passwd = "abc123"
username = input("Username:")
password = input("Password:")
if username == _user and password == _passwd:
print("Welcome %s login..." %_user)
else:
print("Invalid username or password")
for i in range(3):
print(i)
输出结果
0
1
2
以下代码只能在python2.x才能看出来
for i in range(3):
print("loop:",i)
输出结果
loop: 0
loop: 1
loop: 2
规律:前包后不包
打印1-100的所有奇数
for i in range(1,101):
if i%2 == 1:
print("loop:",i)
方法二:
for i in range(1,101,2):
print("loop:",i)
打印1-100的数字,50-70不打印
for i in range(1,101):
if i>=50 and i<=70 :
continue;
print(i)
方法二:
for i in range(1,101):
if i<50 or i>70 :
print(i)
最多输入3次的案例
for i in range(3):
username = input("Username:")
password = input("Password:")
if username == _user and password == _passwd:
print("Welcome %s login..." %_user)
break
else:
print("Invalid username or password")
原文：http://www.cnblogs.com/darkalex001/p/7493950.html