Question

How would I make a dictionary that has keys that represent not just a single string, but multiple strings (array)?
So each key is tied to an array that I can keep appending new strings to if the key is present in another file?

I am a relatively new Python programmer so I can visualize how my script would work… but alas I can’t think of the proper syntax.

I have the logic down (I think), I just need help with which modules or functions to use in Python. I am about 3/4 the way through Learn Python the Hard Way by Zed Shaw, if you need a reference to my current knowledge in Python.

Lets get to it. Example:

File 1:

A
B
C
D

File 2:

Ted A
Mike A
Wilma B
Frank C
Dog D
Fred D

File 3:

Jon Ted
Sid Ted
Mic Mike
Will Dog
Tod Dog

Hopeful Result (write to File 4):

>A Ted Mike Jon Sid Mic
>B Wilma
>C Frank
>D Dog Fred Will Tod

So using file 1 for the keys we can fill the elements with file 2 and 3 if the key is present. Notice in file 2 A and D have multiple answers. Next look into file 3 and we expand even further; we also see that Jon and Sid(file3) = Ted(file2) = A. A also = Mike (file2) = Mic (file 3)

This is the simplest example of my data (100,000’s of sequences), and the real kicker is I have five hierarchically expanding files, not just 2 (example above).

~~~ Answered ~~~

Thank you F.J and others

Answer 1

The following should work:

keys = []
data = {}
names = {}

for line in open('file1', 'r'):
    keys.append(line.strip())
    data[line.strip()] = []

for line in open('file2', 'r'):
    name, key = line.strip().split()
    if key in data:
        data[key].append(name)
        names[name] = key

for line in open('file3', 'r'):
    nickname, name = line.strip().split()
    if name in names:
        data[names[name]].append(nickname)

with open('file4', 'w') as file4:
    for key in keys:
        file4.write('>{0} {1}\n'.format(key, ' '.join(data[key])))