Why is this happening?

Python
1

So basically, I use Python, a popular programming language. There’s this one problem that I just don’t understand why happening. I’m learning " Accessing 2D lists in Python" which my code was like:

class_name_test = [["Jenny", 90] ["Alexus", 85.5 ["Sam", 83] ["Ellie",101.5]]
print(class_name_test)

What it gave me:

File "script.py", line 2
    print(class_name_test)
        ^
SyntaxError: invalid syntax

What’s happening? Please give me advice.

2

Your array isn’t written with correct syntax

3

Thanks but, the error is in the print statement not the array.

4

there are missing commas between some of the inner lists.

5

Thanks but the error is in the print statement.

6

you missed commas between the inner lists’ elements. Each inner list should be separated by a comma to distinguish one list from another within the main list

7

The errors in the array are confusing Python. You need to fix the array.

8

But then why does it tell me there is an error in the print statement if your telling me the array is confusing Python?

9

I would not get too hung up on this. You have an error in a two line program and the print statement is very simple. You can see there is no syntax error there.

There is a concept called “traceback” where you might get an error in a statement but it’s caused by a previous statement and you need to “trace back” to what caused the error. Sometimes you will get a more detailed traceback error that follows the error to it’s source.

Not sure what you are using to code, but I put this program into Google Collab and it shows this error:

File "<ipython-input-1-875ad81545af>", line 1
    class_name_test = [["Jenny", 90] ["Alexus", 85.5 ["Sam", 83] ["Ellie",101.5]]
                      ^
SyntaxError: '[' was never closed

It might be more helpful. In any case if you look closely at your array, you are clearly missing a bracket. Make it easier to look at:

class_name_test = [
    ["Jenny", 90] 
    ["Alexus", 85.5 
    ["Sam", 83] 
    ["Ellie",101.5]
]

Does this help?

2 Likes
10

Thanks man! It really helped a lot but the error has got changed into a type error after fixing the code.
My code:

class_name_test = [
  ["Jenny", 90] 
  ["Alexus", 85.5] 
  ["Sam", 83] 
  ["Ellie",101.5]
  ]

I fixed the error in Alexus list then,
the terminal:

Traceback (most recent call last):
  File "script.py", line 3, in <module>
    ["Alexus", 85.5] 
TypeError: list indices must be integers or slices, not tuple

If you can’t help me out it is fine.

1 Like
11

What you have here is a nested list. A list within a list. All list elements have a comma between them. ["Jenny", 90] Here is a list with two elements. It’s contained within a list of lists. Now that “outside list” I do not see commas

https://www.learnbyexample.org/python-nested-list/

For what you are building though, a dictionary might be better

https://www.w3schools.com/python/python_dictionaries.asp

1 Like
12

Thanks man, you helped me get through this. And thanks to the others who helped me too.

2 Likes
13

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