Form 4 - Computer
2024-2025
Floor 4 - Computer Room
Mr. Peter
While Loop & List
Santa Rosa de Lima English Secondary School
聖羅撒英文中學
Colégio de Santa Rosa de Lima - Secção Inglesa
Outline
List
1.
Explore the concept of List
How to process List in While Loop
2.
Focusing on the List processing in looping
Python List implementation
3.
Define while loop statement for List scanning
What is List?
What is List?
0
1
...
[
]
2
1
4
1
1
1
3
1
boxes =
In Python:
boxes = [ 1, 1, 1, 1, 1 ]print( boxes[ 0 ] )Get variable from List
list[ position ]
Output: 1
What is List?
0
a
"
"
2
c
4
e
1
b
3
d
text =
We can also get letter from text
text = "abcde"print( text[ 0 ] )Get letter from text
Output: a
text[ position ]
Python List Exercises
Python List - Ex01
Collect Five Positive Numbers
1.
numbers = [12, -7, 34, -19, 8, -3, 25, -42, 16, -11, 7, -28, 45, -9, 5, -14, 20, -6, 33, -21]
Save your file as "ClassNumber_YourName_Ex01.py"
Use a while loop to collect exactly five positive numbers from the numbers variable. Append each valid number to a list. If the number is a negative number, ignore it. Print the list at the end.
2
3
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Append only the positive numbers (greater than 0) to a new list if the number of items in list is less than 5 items.
Print the final list containing the first positive numbers.
Python List - Ex02
Separate Even and Odd
1.
numbers = [12, -7, 34, -19, 8, -3, 25, -42, 16, -11, 7, -28, 45, -9, 5, -14, 20, -6, 33, -21]
Loop through the numbers variable. Append even numbers to a list called evens and odd numbers to a list called odds. Print both lists.
If an element is even, append it to the evens list. If it is odd, append it to the odds list.
2
Finally, print both the evens and odds lists.
3
Save your file as "ClassNumber_YourName_Ex02.py"
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Python List - Ex03
Splitting a List into Multiple Increasing Sequences
1.
numbers = [10, 15, 20, 5, 7, 9, 2, 3, 1, 4]Write a Python program that processes a given list of numbers and separates it into multiple sublists. Each sublist should represent an increasing sequence. Whenever a number in the list is smaller than the previous number, start a new sublist.
Save your file as "ClassNumber_YourName_Ex03.py"
Expected Output:
1
[10, 15, 20]
[5, 7, 9]
[2, 3]
[1, 4]* Separate list into increasing sequences