= Receita: Exemplo de uso do Pickle =

Código de exemplo sobre o uso do Pickle. É um mini gerenciador para grade curricular.
Ele usa o cPickle, por questão de desempenho, mas nada que impeça de usá-lo com o Pickle normal.

== Código ==

{{{
#!python
import cPickle


def write_file():       
    """
    Funcao que escreve num arquivo um dicionario.
    Isto eh, escreve um arquivo binario de um objeto
    Python usando o Pickle
    """
    CIT = ["Academic Computer Skills", "Database Management", "Intro to Computer scince",\
        "ACCESS","Systems Analysis and Design", "Visual Basic",\
        "Intermediate Visual Basic", "Decision Support Using Excel"]
    pickle_file = open("pickles1.dat","w")

    cPickle.dump(CIT, pickle_file)
    print "A file has been created and the required specifications have been added"
    pickle_file.close()


def read_file():
    """
    Le o dicionario do arquivo.
    """
    pickle_file = open("pickles1.dat","r")
    CIT = cPickle.load(pickle_file)
    pickle_file.close()
   
    for course in CIT:
        print CIT.index(course), "-", course


def delete_file():
    """
    Deleta uma entrada do dicionario
    Tambem atualiza no arquivo.
    """
    word_delete = int(raw_input("Which record do u want to delete?[key of the record]: "))
   
    pickle_file = open("pickles1.dat", "r")
    CIT = cPickle.load(pickle_file)
    pickle_file.close()
   
    try:
        CIT.pop(word_delete)
        pickle_file = open("pickles1.dat","w")
        cPickle.dump(CIT, pickle_file)
        pickle_file.close()
    except:
        print "There isnt a record with this key"


def add_record():
    """
    Adiciona um registro ao dicionario.
    Tambem atualiza o arquivo
    """
    pickle_file = open("pickles1.dat", "r")
    CIT = cPickle.load(pickle_file)
    CIT.append("SQL Programming")
    CIT.append("Database Programming")
    pickle_file.close()
   
    pickle_file = open("pickles1.dat","w")
    cPickle.dump(CIT, pickle_file)
    print "New data was added to the file"
    pickle_file.close()


def display_instructions():
    """Display the Main menue"""
    print \
          """
        Main Menu:
        
          1. Exit
          2. Create a new file and add specifications
          3. Add more courses to the file
          4. Read the file
          5. Delete a course
          6. Display instructions

          """


# exit the program                               >>> 1 <<<
def over_program():
    """Exit the program"""
    print "Good Bye!"

  
def main():
    choice = None
    display_instructions()
  
  
    while choice != 1:
        choice = raw_input("\nChoice: ")
        if choice == "1":
            over_program()
            break
  
        elif choice == "2":
            write_file()

        elif choice == "3":
            add_record()
          
        elif choice == "4":
            read_file()

        elif choice == "5":
            delete_file()
       
        elif choice == "6":
            display_instructions()

        else:
            print "\nSorry, but %s isn! 't a valid choice."%(choice)


main()
raw_input("Press Enter Key to Exit.")    
}}}


Volta para CookBook.

----

Murtog
----
CategoryTemplate