How would you iterate through a library where the index keys are given as integers, but are predefin-CodePudding

I have a dictionary which looks like this and is already part of a constructor :

self.__books = {
                    1001: {'title': 'Introduction to Programming', 'author': 'Farell', 'copies': 2}, 
                    1002: {'title': 'Database Concepts', 'author': 'Morris', 'copies': 5}, 
                    1003: {'title': 'Object Oriented Analysis', 'author': 'Farell', 'copies': 4}, 
                    1004: {'title': 'Linux Operating System', 'author': 'Palmer', 'copies': 2}, 
                    1005: {'title': 'Data Science using Python', 'author': 'Russell', 'copies': 4}, 
                    1006: {'title': 'Functional Programming with Python', 'author': 'Babcock', 'copies': 6}
                    }

What I am trying to do is print the dictionary but in a string format ( for example -

     1001 : title: Introduction to Programming, author: Farell, copies: 2 (\n)
     1002 : .... ( Hope you get the idea))

As per the problem given, I have to create a property called books that gets the value of 'self.__books' so it can be displayed and referenced w/o changing the original value of 'self.__books' in the future, so that the original can be referenced, if needed ( I also have to practice adding and removing from the list hence the need for the property and not just an attribute - correct me if I misunderstood the idea please.) I have looked up a bunch of resources that explain how to iterate through a dictionary using the key,value method like so -

    def books(self):
         for (key,value) in self.__books : 
            return  "{0} : {1}".format(key,value)

And all I am getting is an error message that says the compiler 'cannot unpack non-iterable int object'

I do understand that the 1001 is an int, hence the problem when the process starts, but I cannot figure out how to reference the value of the item at that index when the key is an integer ( the key was already given to differentiate the index values - I do not know what such a key would be called i.e, like a 'index key' or 'indexer' maybe?) Maybe the formatting of the original dictionary 'self.__books' stops it somehow ?

Any help would be appreciated and thank you in advance for taking the time to read this.

CodePudding user response：

You must iterate by dict as:

for key in self.__books:
    return "{0} : {1}".format(key,self.__books[key])

CodePudding user response：

def books(self):
    for (key,value) in self.__books.items() : 
    return "{0} : {1}".format(key,str(value).replace('{','').replace('\'','').replace('}',''))

I think this will do the trick.

CodePudding user response：

Dict have keys() and items() methods for iteration. Here in your case the item inside the dict is another dict, try something like below:

for k in self.__books.keys():
  ls = self.__books[k]
  ss = ""
  i = 0
  for j in ls.keys():
    if i > 0:
      ss = ss   ", "
    ss = ss   str(j)   ": "   str(ls[j])
    i  = 1
    
  print("{0} : {1}".format(k, ss))