TypeError：列表索引必须是整数或切片，而不是Slot

Question

I am trying to access values of a list containing instances of a Class

This is how I store the elements in a list

class Slot:
    def __init__(self, slot, available):
        self.slot = slot
        self.available = available

for i in range(rangeHours):
    timeSlots.append(i)
    timeSlots[i] = Slot(hours[i],free[i])

This is the code that gives me an error

for call in calls:
    if call == 1:
        for i in timeSlots:
            if timeSlots[i].available == True:
                patient[i] = Patient(timeSlots[i].slot)
                timeSlots[i].available == False

Error code:

if timeSlots[i].available == True: TypeError: list indices must be integers or slices, not Slot

Thank you for your help.

Answer 1

You should use a dict instead of a list . You can also use a list for the same purpose, but not the way you structured your code. Why? Let's see in detail what you are doing:

# Lets say you have an empty list:

time_slots = []

You loop through integers and append them into your list:

for i in range(rangeHours):
    time_slots.append(i)

After the first iteration, you list will be:

# time_slots = [0]

Then you are accessing the same element you have just appended using it as index:

# time_slots[0] = 0 , which in this case, the element you accessed is 0

Then you change this element to be your Slot class:

# time_slots[0] = Slot(hours[0],free[0])

Which directly overwrites what you have just put into your list. In short, time_slots.append(i) has no effect.

I think you should use a dict instead:

time_slots = {}
for i in range(rangeHours):
    time_slots[i] = Slot(hours[i],free[i])

Then you can do:

for call in calls:
    if call == 1:
        for slot_index, slot_class in time_slots.items():
            if slot_class.available == True:
                patient[slot_index] = Patient(slot_class.slot)
                slot_class.available == False