Files and Strings(Chapter 10 of Python 3 Object Oriented Programming)

 1 >>> template = "Hello {}, you are currently {}."

 2 >>> print(template.format('Ray', 'writing'))

 3 Hello Ray, you are currently writing.

 4 >>> template = "Hello {0}, you are {1}. Your name is {0}."

 5 >>> print(template.format('Ray', 'writing'))

 6 Hello Ray, you are writing. Your name is Ray.

 7 >>> template = """

 8 public class {0} {{

 9 public static void main(String[] args) {{

 System.out.println({1});

 }}

 }}"""

 >>> print(template.format("MyClass", "print('hello world')"))

 

 public class MyClass {

 public static void main(String[] args) {

 System.out.println(print('hello world'));

 }

 }

 >>> template = """

 From: <{from_email}>

 To: <{to_email}>

 Subject: {subject}

 {message}"""

 >>> print(template.format(from_email="a@a.com", to_email="b@b.com", message="message", subject="You got a new message"))

 

 From: <a@a.com>

 To: <b@b.com>

 Subject: You got a new message

 message

 >>> print("{} {label} {}".format("x", "y", label="z"))

 x z y