使用 % 将字典中的value嵌入到字符串中对应的key值中
dd = {"a":1,"b":2,"c":3}
txt = "this is a test : a is %(a)s, b is %(b)s, c is %(c)s "
print txt % dd
结果为：
this is a test : a is 1, b is 2, c is 3
使用 % 将字典中的value嵌入到字符串中对应的key值中
dd = {"a":1,"b":2,"c":3}
txt = "this is a test : a is %(a)s, b is %(b)s, c is %(c)s "
print txt % dd
结果为：
this is a test : a is 1, b is 2, c is 3