How can I implement existing code into a fuction?-CodePudding

I found out that this is what I am struggling the most. I know how to write a function:

     def test(a,b):
        for x in range(20):
        if x == 15:
            return
    print("test")
    test()

but I don't know how to create a function with something already written:

contacts = {"Alice": " 1554", "Bob": " 1885", "Carol": " 1006", "Felix":" 1604", "Max":" 1369","Chris":" 1882","Lea":" 1518","Linn":" 1742","Julia":" 1707"}

def phone_book(name,book):
    if name in contacts:
        return book

while True:
    print('Enter a name: (blank to quit)')
    name = input()
    if name == '':
        break
    if name in contacts:
        print(contacts[name]   ' is the number of '   name)

I cannot bring to this code to work if I try to utilize a function. Can you explain me how to do this? You don't need to write the code. I really want to understand it.

CodePudding user response：

A function is a way that allows you to automate a certain process in your code.

In your test function, you define 2 parameters so that means you have to provide those 2 variables in order for that function to work. A simple function could be as well as

def test(a,b):
        c = a   b
        print("The sum of  number "   str(a)   "   "   str(b)   " is "   str(c))
test(5, 5)

if you pay attention to the last line I provide the function name along with those 2 variables, only that now they have values (they are now called arguments)

Hopefully the links below can give you more clarifications

https://www.w3schools.com/python/python_functions.asp

Basic explanation of python functions

CodePudding user response：

You can have the function return the formatted string. Then the main code calls the function and prints what it returns.

def phone_book(name,book):
    if name in book:
        return f'{book[name]} is the number of {name}'
    else:
        return f'{name} is unknown'

while True:
    print('Enter a name: (blank to quit)')
    name = input()
    if name == '':
        break
    print(phone_book(name, contacts))

CodePudding user response：

Please Just structure it in a class.

class contact_book:
  def __init__(self):
    self.contacts = {"Alice": " 1554", 
                     "Bob": " 1885", 
                     "Carol": " 1006"}

  def add(self, name, value): self.contacts[name] = value
  def phone(self, name): return self.contacts[name]
  def do_i_know_you(self, name): return name in self.contacts
  def __str__(self): return f"Known contacts are: {list(self.contacts.keys())}"

Usage:

myBook = contact_book()
myBook.add('brian', '4411')
print(myBook) 
print(myBook.do_i_know_you('Martin'))

Result:

Known contacts are: ['Alice', 'Bob', 'Carol', 'brian']
False