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Lab notes on getting going thru the early parts of Tasty lab.

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TastyHints.md Brut

Tasty Lab Hints

Hint 3

Student Asks: I'm struggling to see where we take the user input for the task name.

If we have command = input('Tasty> ')

So the command variable will have exit or whatever, after the user types something in and taps , right?

And the new <task> command/line when entered, will actually look like new Buy Milk when user types the command to be processed by the program.

so take the string inputted and split it into a list of strings, breaking each string on the character.

txt = "command typed by user"

x = txt.split()

print(x)

# x will be a  list: ['command', 'typed', 'by', 'user']

If we want to extend this to make two new strings:

  • command (the first string, perhaps "new")
  • and rest (the rest of the split strings glued back together with spaces in between...)
txt = "new Buy Milk"
t = txt.split()
print(t) # t will be: ["new", "Buy", "Milk"]
command = t[0] # command will be "new"
rest = t[1:] # carefully: Slice the array, from t[1] to end of list
             # rest will be ["Buy", "Milk"]
rest = " ".join(rest) # now rest will be "Buy Milk"
print(command, ' - ', rest)

and after hacking a bit in the python interpreter, you may end up with

  line = input(prompt)
  #print(line)
  while not line:
    line = input(prompt) # this causes input to wait until 
                         # line is not an empty string
  words = line.split()
  #print(words)
  command = words[0]
  #print(command)
  rest = words[1:]
  rest = " ".join(rest)
  #print(rest)

and maybe the right thing to do is to change the command = input("Tasty> ") to something like command, rest = tasty.prompt_user("Tasty> ")

then all the "words" after the "new" will be what you pull together to name the task?

so prompt-user(self, prompt) becomes a method which asks for the user's input (using input(prompt))

def prompt_user(self, prompt):
  inp = input(prompt)
  # insert the stuff up there about how to 
  # split words into a list and process into two parts.

Saving/Loading to a JSON file

JSON is just a structured text format for data. Very Handy.

saving? a Hint

with open("saved_data.json", "w") as fp:
  json.dump(self.tasks,fp)

loading? a Hint

with open(filename) as json_file:
  self.tasks = json.load(json_file)

And you should embed these two ideas into a method.

When you get to the point where you are puzzling over how to save/load multiple dicts (say, tasks, trash, and important), you might consider putting all this in another dictionary and just saving that.

You still have to load the one dict and then split it into three for use by the methods. This should be done in load tasks method.

The data structure might be created by

dict_to_save = { "tasks": self.tasks, "trash": self.trash, "impt": self.important }

You can now json.dump the dict_to_save to a file.

Loading it will be the opposite, you end up with one loaded_dicts which have to be split like: self.tasks = loaded_dicts['tasks']

Easy Peasy