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