Someone please solve this.

Question

Hello,
The following code was written by someone else.
**It is working fine**
textbooks = {
("Maths","Calculus") : 600,
("Maths","Algebra") : 450,
("Science","Physics") : 700,
("Science","Chemistry") : 650
}

student_borrow = ("Maths","Calculus")
pages = textbooks[student_borrow]
print(pages)

but when I change student_borrow = input()
**because I want to take input from user** **it's showing error**
textbooks = {
("Maths","Calculus") : 600,
("Maths","Algebra") : 450,
("Science","Physics") : 700,
("Science","Chemistry") : 650
}

student_borrow = input()
pages = textbooks[student_borrow]
print(pages)

Can someone please explain why I can't able to take input from user?
Thanks in advance!!!

Answer 1

Because input is string but you need it in format ("Maths","Calculus")

Input will be '("Maths","Calculus")',

You can wrap keys to be string like this:

textbooks = {
'("Maths","Calculus")' : 600,
'("Maths","Algebra")' : 450,
'("Science","Physics")' : 700,
'("Science","Chemistry")' : 650
}

student_borrow = input()
pages = textbooks[student_borrow]
print(pages)

Now code will accept input because format is same

PS: error code exualy was showing you exacly format, that there are not key '("Maths","Calculus")', note single quote.