A dictionary for ever

When you write data into an object (list, set, dictionary, e.g.),  save this object in a file may be very useful. By this, you can access to data structure without re-build it from scratch.


The python module that allows to perform this is pickle.
For example, take a txt file containing the genetic code data, and try to seve a dictionary.
 


#!/usr/bin/python
import pickle
GC=open('genetic_code.txt','r').readlines()
D={}
for i in GC:
        line=i.split()
        codons=line[-1].split(',')
        for c in codons[:-1]:
                D[c]=line[1]
g=open('dictionary','w')
pickle.dump(D,g)
g.close()


Now you will find a file named 'dictionary' in the working directory.
Opening the file, you will see nothing of readable, but you can import and use the file when the dictionary will serve you.
In order to import the dictionary you have to use this syntax:


import pickle
F=open('dizionario','r')
D=pickle.load(F)




Now the variable D is your dictionary again.

In spite of the post title, the procedure works also with lists, sets and whatever you want immortalize.