python format函数用法详解：
1、位置
print("hello {0}, this is {1}.".format("world", "python")) # 根据位置下标进行填充
print("hello {}, this is {}.".format("world", "python")) # 根据顺序自动填充
print("hello {0}, this is {1}. {1} is a new language.".format("world", "python")) # 同一参数可以填充多次
输出：
hello world, this is python.
hello world, this is python.
hello world, this is python. python is a new language.
2、key
obj = "world"
name = "python"
print("hello {obj}, this is {name}.".format(obj = obj, name = name))
输出：
hello world, this is python.
3、列表
list = ["world", "python"]
print("hello {names[0]}, this is {names[1]}.".format(names = list))
输出：
hello world, this is python.