How to append variables in nested list in python

Question

if __name__ == '__main__':
    for _ in range(int(input())):
        name = input()
        score = float(input())
        a=[]
        a.append([name][score])
    print(a)

This is error occurred when I insert values

Traceback (most recent call last):
  File "C:/Users/Administrator/Desktop/Nested Lists.py", line 6, in <module>
    a.append([name][score])
TypeError: list indices must be integers or slices, not float

Answer 1

The syntax to make a list containing name and score is [name, score] . [name][score] means to create a list containing just [name] , and then use score as an index into that list; this doesn't work because score is a float , and list indexes have to be int .

You also need to initialize the outer list only once. Putting a=[] inside the loop overwrites the items that you appended on previous iterations.

a=[]
for _ in range(int(input())):
    name = input()
    score = float(input())
    a.append([name, score])
print(a)

Answer 2

Use a dictionary instead of a list (a list will work, but for what you are doing a hashmap is better suited):

if __name__ == '__main__':
    scores = dict()
    for _ in range(int(input())):
        name = input()
        score = float(input())
        scores[name] = score
    print(scores)

Answer 3

As others have told, a dictionary is probably the best solution for this case.

However, if you want to add an element with multiple values to a list, you have to create a sublist a.append([name, score]) or a tuple a.append((name, score)) .

Keep in mind that tuples can't be modified, so if you want, for instance, to update the score of a user, you must remove the corresponding tuple from the list and add a new one.

In case you just want to add new values to a flat list, simply go for a = a + [name, score] . This will add both name and score to the end of the list as entirely independent elements.

Answer 4

if __name__ == '__main__':
deva=[]
for _ in range(int(input())):
    name = input()
    score = float(input())
    l=[]
    l.append(name)
    l.append(score)
    deva.append(l)
print(deva)