How to store the result of an executed function and re-use later?

Question

E.g., I have:

def readDb():
    # Fetch a lot of data from db, spends a lot time
    ...
    return aList

def calculation():
    x = readdb()
    # Process          


        

Answer 1

def readDb():
    ... #Fetch a lot of data from db, spends a lot time
    return aList

def calculation(data):
    x=data
    ...process x...
    return y

data = readDb()

calculation(data)
calculation(data)
calculation(data)

This will only hit the database once.

Basically, you want to save the results of readDb() to a seperate variable which you can then pass to calculation().