format 函数可以通过以下方式调用：
{} 占位符，然后调用 format 函数将需要填充的值传递进去，示例如下：name = "Alice"
age = 25
print("My name is {}, and I am {} years old.".format(name, age))
输出结果为：My name is Alice, and I am 25 years old.
name = "Bob"
age = 30
print("My name is {0}, and I am {1} years old.".format(name, age))
输出结果为：My name is Bob, and I am 30 years old.
name = "Charlie"
age = 35
print("My name is {n}, and I am {a} years old.".format(n=name, a=age))
输出结果为：My name is Charlie, and I am 35 years old.
此外，format 函数还可以用于格式化数字、日期等特定类型的值，具体用法可以参考 Python 官方文档。
