Array vs file, in simple python app -

I want to create a name-day calendar but I have to fight with a question, which method is to improve

Load all names and dates in an array
1. Create a file and every time I match a specific name, find out I
2. Another method? <

   Use a word (name is considered unique):

     {'name1': 'someday', 'name2': 'someday', ...}   
    as the key and related day values In form of.  
    Dikes  o (1)  provide look for any item, while the  O (N)  lookup is in the list.  
    Rather than saving the data to text, the files use the module as if you allow python objects to be stored. You can later load those items in memory and use them.