Saving a String, List, or Dictionary as a .txt file

Question

What I want to do is be able to modify a string, list, or dictionary during the program and be able to save the modified string, list, or dictionary as the starting data for the next time I run the program. Can anyone show me how its done?

Ex: Strings

stringFile = open('stringName.txt', 'wt')

myString = 'Hello'

Now modify the string,

myString.upper()
if 'l' in myString:
    myString = myString.replace('l','k')
    myString += ' World'


stringFile.write(str(myString))
stringFile.close()

---

Ex: Lists

listFile = open('listName.txt', 'wt')

myList = [10,1,21,3,4,11,9,13,14]

Now modify the list,

myList.append(24)
myList = myList.sort()

listFile.write(str(myList))
listFile.close()

---

Ex: Dictionary

dFile = open('dictionaryName.txt', 'wt')

myDictionary = {
1: 'Hydrogen',
2: 'Helium',
3: 'Lithium',
4: 'Beryllium',
5: 'Boron',
6: 'Carbon',
7: 'Nitrogen',
8: 'Oxygen',
9: 'Fluorine',
10: 'Neon',
}

Now modify the dictionary,

myDictionary[11] = 'Sodium'
myDictionary[12] = 'Magnesium'

keys = myDictionary.keys()
values = myDictionary.values()

dFile.write(str(keys))
dFile.write(str(values))
dFile.close()

---

Now, that I have modified my string, list, and dictionary...I want to close the program and be able to start with that modified data for next time. HOW DO I DO THAT???

If you notice any errors above, please tell me

Thank You

Answer 1

The easiest way to store data so that it can be retrieved at a later time is to serialize it. A common format for serialization is JSON .

import json

with open(..., 'w') as fp:
  json.dump(val, fp)

And to deserialize it:

import json

with open(..., 'r') as fp:
  val = json.load(fp)