While Loops and Arrays in Python

Valid While Loops

• Valid while loop example: x = 1; while x <= 5: x += 1
• This loop initializes x to 1 and continues as long as x is less than or equal to 5

Array Declarations

• Valid array declaration: arr = array.array('i', [1, 2])
• Invalid array declaration: a = arr.array('i', [12])

Printing Array Values

• Valid array printing: for n in a: print(n, end=" ")
• Valid array printing (alternative): for n in range(len(a)): print(a[n], end=" ")
• Invalid array printing: for n in range(len(a)): print(n, end=" ")

Printing Array Length

• Valid way to print array length: print(len(a))

Code Output Analysis (Question 6-11)

• Consider the initial array a = [6, 3, 7, 2, 3, 4]
• a.insert(2, 9) inserts 9 at index 2, resulting the new array as [6, 3, 9, 7, 2, 3, 4] will print the updated array elements
• a.append(9) adds 9 to the end of the array, resulting in [6, 3, 7, 2, 3, 4, 9] will print these elements
• a.pop(3) removes element at index 3 (which is 2) from the array, resulting in [6, 3, 7, 3, 4] will print these elements

For Loop Output Analysis (Question 12)

• The output of the code for n in range(2): print("*", end=" "); for m in range(2): print("*", end=" "); print() is ****

While Loop Output Analysis (Question 13-14)

• Output of x=1; while x<=3: print("#", end=' '); x+=1 is # # #
• Output of x=1; while x>=3: print("#", end=' '); x+=1 is empty or nothing

While Loop Conditions Analysis (Question 15-17)

• continue statement skips the rest of the code inside the loop if the condition is met.
• break statement will exit the loop entirely.
• Understanding the if conditions is crucial for determining the output of the while loop logic.

Array Methods (Question 18-19)

• a.index(element) returns the index of the first occurrence of the element in array a.
• Import array as ar is used in question 19.

Array Operations (Question 20-22)

• Array methods like insert(), remove(), append(), and pop() modify the array in-place.
• The loops iterate through the elements of the array a after applying these methods and print the elements
• a.slice() return a sub-array of a from the given index to the end.

Code Completion (Question 23)

• Correct answer depends on which elements the question asks for from the array.

Function Signature (Question 25-27)

• Valid function signature format example: def myFunc(arg1, arg2)

  • Correct Function signature format example: def myFun(argA = 5, argB = 7)

• Invalid format (and examples of why it is invalid): def myFun (argA argB = 7)

Function Output (Question 28-29)

• Function add does a simple addition calculation
• The correct output for question 28 and 29 depends on what the question asks for in term of what will be returned by function.

More Code Outputs (Question 30-33)

• The outputs in these questions are determined by the code's logic, including function calls.