type error: can't use - for list or integer

Question

what i can do for this code?
https://code.sololearn.com/cpj40S46B1WC/?ref=app

Answer 1

https://docs.python.org/3/library/sqlite3.html

Yes execute(SELECT) returns a list, even though by fixing id as 1 there is only one entry.

Answer 2

it turns out that select produces list of dictionaries. so
a =a[i] ["key"]
and its worked, thank you all.

Gordon Maninder $ingh thank you very much

Answer 3

I think when you define c variable then something is wrong please check your code again.

Answer 4

print(type(a))

If a is list
Use a[0] to get the number first, then type cast to float

Answer 5

a = float(a)
c = float(c)