Error when converting working code to a more object oriented structure Error: string indices must be integers Python 3

Question

I keep running into the error: string indices must be integers when using placeholders for my script.

My program is supposed to track the growth of veggies purely on calculation. The idea is that each plant has it's own characteristics (eg carrotData) but instead of having code for each 'plantData' I replaced the code with (whichPlant and later whichPlantData) as a temporary placeholder (so that I don't need new code for each plant I have in my garden or that I want to add at a later point).

This is when I get the error in the last line (Plant is a class) marked with the ***. When I use (carrotData) instead of (whichPlantData) my script works. But as soon as I put in the temporary placeholder (whichPlantData) is breaks.

What causes this (so that I can avoid doing this in future projects) and how can I fix this?

thanks for the support!!

carrotData = {'plantID': '','plantingTime': dt(year=now.year, month=3, day=1), "dateOfPlanting": 0, "numberOfPlants": 0, "germinationTime": 7, "growthTime": 227, "flowerTime": 247, "harvestTime": 254, "liveCycles": 1, "status": 0}
potatoData = {'plantID': '','plantingTime': dt(year=now.year, month=3, day=1), "dateOfPlanting": 0, "numberOfPlants": 0, "germinationTime": 7, "growthTime": 227, "flowerTime": 247, "harvestTime": 254, "liveCycles": 1, "status": 0}

print ("imported plant datasheets")

#functions:

#if plant is added

def addPlant():
    whichPlant = input("Which plant do you want to add? ")
    n = int(input("How many plants do you want to add? "))
    i = 0
    whichPlantData = whichPlant + "Data"

    if whichPlant in inventory:
            while i < n:
                    i += 1
                    if whichPlant in plants:
                            plants[whichPlant] += 1
                    else:
                            plants[whichPlant] = 1
        ***Error*** whichPlant = Plant("", whichPlantData['plantingTime'], dt.now(), n, dt.now() + timedelta(days=whichPlantData['germinationTime']), dt.now() + timedelta(days=whichPlantData['growthTime']), dt.now() + timedelta(days=whichPlantData['flowerTime']),whichPlantData['harvestTime'], whichPlantData['liveCycles'], whichPlantData['status'])

Answer 1

Your problem seems to be with whichPlantData = whichPlant + "Data". whichPlant is a string returned by the input function. I think what you're trying to do is get a dictionary of plant information based on input from the user. Furthermore; whichPlant + "Data" seems like an attempt at making whichPlant the same as a variable name pointing towards a dictionary of plant information. Just because the string whichPlant may be equal to the variable name carrotData does not make it the same as the variable. I would suggest making a list of dictionaries full of the information about the plant then iterate over the items in that list to see if the dictionaries name key is the same as the user input. Similar to this:

plants = [{"Name": "Carrot", 'plantID': '','plantingTime':0, "dateOfPlanting": 0, "numberOfPlants": 0, "germinationTime": 7, "growthTime": 227, "flowerTime": 247, "harvestTime": 254, "liveCycles": 1, "status": 0},
{"Name": "Potato", 'plantID': '','plantingTime': 0, "dateOfPlanting": 0, "numberOfPlants": 0, "germinationTime": 7, "growthTime": 227, "flowerTime": 247, "harvestTime": 254, "liveCycles": 1, "status": 0}]

PlantName = input("Enter a Plant: ")

for plant in plants:
    if plant['Name'] == PlantName:
        print("{}'s germinationTime is {}".format(PlantName, plant["germinationTime"]))
        # DO SOMETHING