如何在字典中获取匹配的 substring 键并在 Python 上返回相应的值？

Question

New to python and lots to learn. I'm trying to return dictionary (plantdict) values with substring key input by users. Below is my code so far.

 def search_plant_name():
    while True:
        enter_plant_name = input('Please enter plant name: ').capitalize()
        filtered_dict_key = [key for (key, val) in plantdict.items() if enter_plant_name in key]
        filtered_dict_time = [val[0] for (key, val) in plantdict.items() if enter_plant_name in key]
        filtered_dict_info = [val[1:] for (key, val) in plantdict.items() if enter_plant_name in key]
        if ##NOT SURE WHAT TO WRITE HERE## in plantdict.items():
            print('Plant name:', str(filtered_dict_key).strip("[]").replace("'",""))
            print('Date and time of entry/revision of plant record:', str(filtered_dict_time).strip("[]").replace("'",""))
            print('Information of plant:')
            print('Date and time of entry/revision of plant record:', str(filtered_dict_info).strip("[]").replace("'",""))
        else:
            provide_option_2 = user_input_options('The plant does not exist, would you like to add in the record? (Y / N): ')
            if provide_option_2 in ('Y'):
                print('OPTION2')
                ##CREATE FUNCTION FOR OPTION 2##

The idea is that eg if user keyed in "roses" and my dictionary has "Red Roses" as a key, it will return the corresponding values of this key. But if the user keyed in a word/phrase that does not match any of my keys, s/he be given an option to add plant details to the dictionary, hence Option 2

Not sure what I'm doing wrong, or what could be missing. Any help will be grately appreciated. Thank you very much.

Answer 1

filtered_dict_key is a list, not a string. .strip() isn't an operation that works on a list, only strings. The brackets: '[]' aren't string characters - they have separate meaning to python.

Your while loop will also run forever, but I assume that's not the issue at hand.

Instead of writing list comprehensions, ('[i for i in l if i == v]'), simply write your own for loop. A list comprehension will loop anyhow.

def search_plant_name():
    keep_going = True
    while keep_going:
        enter_plant_name = input('Please enter plant name: ').capitalize()
        for key, val in plantdict.items():
            if enter_plant_name in key:
                print("Plant name: " + key)
                print("Date and time of entry/revision of plant record: " + val[0])
                print('Information of plant:')
                print('Date and time of entry/revision of plant record: ' + val[1])
                keep_going = False  # or put this wherever you want to exit while loop
            else:
                provide_option_2 = user_input_options('The plant does not exist, would you like to add in the record? (Y / N): ')
                if provide_option_2 in ('Y'):
                    print('OPTION2')
                    ##CREATE FUNCTION FOR OPTION 2##

Answer 2

Imho a dictionary is more convenient than a list, because you can have your matching records as they are stored in your little database

matches = {k:plantdict[k] for k in plantdict if plant_name in k}

If you have no matches your matches dictionary will be empty, so if you loop over its items you will do nothing if you have no matches (please edit the format string according to your preferences)

for k, v in matches.items():
    print("""\
Name: $s
Time: %s
Info: %s"""%(k, v[0], v1[]))

At the end you can ckeck if matches is empty and prompt the user accordingly

if matches == {}:
    if input('...')[0].upper() == 'Y':
        ...

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PS I have to say that the design of your function, that never returns, does not appear well thought out…

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PS2 I deliberately avoided ① to use the same variable names as you did and ② to provide executable code.