For a pandas dataframe df, state which of the following statements is correct and which is not? 

  --Not answered-- Correct Not correct --Empty--   1- df.isnull() will find and replace  with 0 all Nan values in the dataframe

  --Not answered-- Correct Not correct --Empty--   2- df[:].isnull().any() will display the names of all  columns that have null in them

  --Not answered-- Correct Not correct --Empty--   3- df['col1'].describe().iloc[1] will return the mean of column ‘col1’

  --Not answered-- Correct Not correct --Empty--   4- df[:].isnull().any(axis=1).sum() will count how many rows have null values in them

  --Not answered-- Correct Not correct --Empty--   5- df.dropna(axis='rows', thresh=4 ) will remove the rows that have less than four non-missing values

  --Not answered-- Correct Not correct --Empty--   6- df = df[ df.isnull().any(axis=1) == False ] will remove the rows with missing values

  --Not answered-- Correct Not correct --Empty--   7- df.dropna(axis=1) is equivalent to df[ df.isnull().any(axis=1 ) == False ]

  --Not answered-- Correct Not correct --Empty--   8- df[ 'col1' ].fillna(1) will replace all nan values of column ‘col1’ with value 0

  --Not answered-- Correct Not correct --Empty--   9- df[ df.notnull().all(axis=1) ] is equivalent to  df.dropna()

  --Not answered-- Correct Not correct --Empty--  10- df.describe( ) will list df's columns and their data types

Your program will take an arithmetic expression as a String input. For Example:

• “1+2*(3/4)”

• “1+2*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14”

• “1+2*[3*3+{4–5(6(7/8/9)+10)}–11+(12*8)/{13+13}]+14”

Program

Your program will determine whether the open brackets (the square brackets, curly braces and the parentheses) are closed in the correct order.

Outputs:

Output 1

1+2*(3/4)

This expression is correct.

Output 2

1+2*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14

This expression is NOT correct.

Error at character # 10. ‘{‘- not closed.

Output 3

1+2*[3*3+{4–5(6(7/8/9)+10)}–11+(12*8)/{13+13}]+14

This expression is correct.

Output 4

1+2]*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14

This expression is NOT correct.

Error at character # 4. ‘]‘- not opened.

Task 1

Solve the above problem using an array-based stack.

Task 2

Solve the above problem using a linked list-based stack.

1. Complete the following problem using concepts of STACK.
2. If you are using JAVA, you must include the main method as well which should test your other methods and print the outputs according to the tasks.
3. If you are using PYTHON, make sure your code has the methods invoked and proper printing statements according to the tasks.
4. Your program will take an arithmetic expression as a string input. For Example:

    

   • “1+2*(3/4)”

    

   • “1+2*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14”

    

   • “1+2*[3*3+{4–5(6(7/8/9)+10)}–11+(12*8)/{13+13}]+14”

    

   Program

    

   Your program will determine whether the open brackets (the square brackets, curly braces, and the parentheses) are closed in the correct order.

    

   Outputs:

    

   Output 1

    

   1+2*(3/4)

   This expression is correct.

    

   Output 2

    

   1+2*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14

   This expression is NOT correct.

   Error at character # 10. ‘{‘- not closed.

    

   Output 3

    

   1+2*[3*3+{4–5(6(7/8/9)+10)}–11+(12*8)/{13+13}]+14

   This expression is correct.

   
   

   Output 4

    

   1+2]*[3*3+{4–5(6(7/8/9)+10)–11+(12*8)]+14

   This expression is NOT correct.

   Error at character # 4. ‘]‘- not opened.

   Task 1

   Solve the above problem using an array-based stack.

    

   Task 2

   Solve the above problem using a linked list-based stack.

Question 8. [6 MARKS] Consider this code: def sort_guesses (guess_list, answer): (list of float, float) -> dict of (str: list of float) Return a new dictionary where each item in guess_list appears as an item in one of the dictionary's values lists: - each item less than answer is in a list associated with key 'low', - each item equal to answer is in a list associated with key 'correct', and - each item greater than answer is in a list associated with key 'high'. If there are no items associated with one of 'low', 'correct', or 'high', then that string should not appear as a key in the new dictionary. In the table below, we have outlined two test cases for sort_guesses. Add six more test cases chosen to test the function thoroughly. R eturn Value Test Case Description no guesses one low guess guess_list answer [ 5.5 [4.7] 6.0 {'low': [4.7]}