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
Limit Particle Speeds
1.
speeds = [5, 12, 8, 15, 9]
max_speed = 10Save your file as "ClassNumber_YourName_Ex01.py"
In a physics experiment, a sensor records particle speeds (in m/s) in a list. To avoid equipment damage, speeds exceeding a maximum threshold must be capped at that threshold. Using a while loop, modify the list so that any speed greater than the threshold is replaced with the threshold value.
2
3
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Iterate through each number in the speeds array and if it exceeds max_speed, replace the value with 10.
Print the final list.
[5, 10, 8, 10, 9]Python List - Ex01
Limit Particle Speeds
1.
speeds = [5, 12, 8, 15, 9]
max_speed = 10Save your file as "ClassNumber_YourName_Ex01.py"
In a physics experiment, a sensor records particle speeds (in m/s) in a list. To avoid equipment damage, speeds exceeding a maximum threshold must be capped at that threshold. Using a while loop, modify the list so that any speed greater than the threshold is replaced with the threshold value.
2
3
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Iterate through each number in the speeds array and if it exceeds max_speed, replace the value with 10.
Print the final list.
[5, 10, 8, 10, 9]Python List - Ex02
Detect Repeated DNA Sequence
1.
dna_segments = [12, 15, 18, 15, 20]Save your file as "ClassNumber_YourName_Ex02.py"
In bioinformatics, scientists analyze DNA sequences to identify repeated patterns that might indicate genetic anomalies. Given a list of integers representing short DNA segment codes (e.g., nucleotide counts), use a while loop to find and print the first repeated segment code. If no repeats exist, no need to print.
2
3
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Detect duplicate elements within a list using efficient validation.
Print the duplicated number
15Python List - Ex02
Detect Repeated DNA Sequence
1.
dna_segments = [12, 15, 18, 15, 20]Save your file as "ClassNumber_YourName_Ex02.py"
In bioinformatics, scientists analyze DNA sequences to identify repeated patterns that might indicate genetic anomalies. Given a list of integers representing short DNA segment codes (e.g., nucleotide counts), use a while loop to find and print the first repeated segment code. If no repeats exist, no need to print.
2
3
Use a while loop to iterate through the numbers.
1
( The variable "i" increases from 0 to len(numbers) )
Detect duplicate elements within a list using efficient validation.
Print the duplicated number
15Python List - Ex03
Coffee Shop Discounts
1.
prices = [150, 200, 50, 100, 75, 300, 125]
target = 250Save your file as "ClassNumber_YourName_Ex03.py"
A coffee shop offers a discount if two items on the menu add up to a specific total price (in cents). Given a list of item prices and a target total, find the indices of two items that qualify for the discount.
2
3
Use a while loop to iterate through the prices.
1
Use a second while loop to check pairs (inner loop).
Check and find two distinct items summing to the target
150 + 100 = 2504
Print the result
