字典到txt文件

Question

I am trying to write a dictionary to a .txt file. I haven't found an efficient way to add multiple values for keys to a text doc.

players = {}
def save_roster(players):
    with open("Team Roster.txt", "wt") as out_file:
        for k, v in players.items():
            out_file.write(str(k) + ', ' + str(v) + '\n\n')
    display_menu()

I have a dictionary that has multiple values for the key. This part of the program leave me with:

Bryce, <__main__.Roster object at 0x00000167D6DB6550>

Where the out put i am aiming for is:

Bryce, 23, third, 23

Answer 1

Python doesn't inherently understand how to print an object. You need to define the __str__ method in order to tell python how to represent your object as a string; otherwise it will default to the representation you're getting. In your case, I might go with something like

def __str__(self):
   return str(self.position)+", "+str(self.jersey)

or whichever attributes you want to print.

And to read the data back in from the text file:

with open("Team Roster.txt", "r") as in_file:
   for line in in_file:
      player = Roster(*(line.split(", "))
      #do something with player, like store it in a list

Assuming Roster.__init__() is set up appropriately, ie a Roster object is initialized by passing in the parameters in each line of the file in order.