AP CSP Filtering Sorting Practice

10 Questions Big Idea 3 3 Question Types Predict First

AP CSP Filtering, Sorting & Boolean Expressions

Big Idea 3: Algorithms & Programming — Boolean Logic, Filter/Sort Ordering & Algorithm Step Sequencing

Exam Tip: These three question types appear on virtually every AP CSP exam. Keywords in the question stem are your signals — highlighted in yellow throughout this practice set. For ordering questions, always trace the sequence on the table before picking an answer. For boolean questions, ask: “can a single row ever satisfy both conditions simultaneously?”

Your Score 0 / 10

Section 1: Boolean Expressions

Each question shows a spreadsheet. Write the correct AND/OR filter condition.

Before revealing choices: (1) Underline the keywords — at least, or less, AND/OR. (2) Check each condition: does it filter a single value or one of several values? If one of several, you need OR inside. (3) Ask: could a single row ever satisfy both inner conditions at the same time? If not, AND is wrong.

✎ Quick Rule: AND vs. OR for Multi-Value Fields

✗ Wrong — Impossible Condition

(day = "Friday") AND (day = "Saturday")

A single day field holds one value. It can never equal two different strings simultaneously. This expression is always false — nothing is ever counted.

✓ Correct — Either Value Allowed

(day = "Friday") OR (day = "Saturday")

OR allows the field to match either value. A show on Friday evaluates the left side as true; a show on Saturday evaluates the right side as true. Both are counted.

Rule: When the question says “A or B,” “either A or B,” or lists multiple allowed values for one field → use OR between those values. Use AND only when separate conditions must all be true at once.

Write the Boolean Expression

MediumBoolean Filtering

Event Name	Type	Cost ($)	Seats Available
Spring Workshop	workshop	20	5
History Lecture	lecture	20	5
Art Workshop	workshop	30	5
Coding Workshop	workshop	25	0
Design Workshop	workshop	25	3

▮ Green rows = expected matches for this goal

Variables: evType = event type (string) • cost = cost in dollars (number) • seats = seats available (number)

A student wants to count events that meet all three of the following criteria: the event is a workshop, the cost is $25 or less, and at least one seat is available. Which expression evaluates to true for events that should be counted?

AND vs. OR — The Day-of-Week Trap

HardBoolean Filtering

⚠Watch for: Ask yourself: can a single show be on Friday and Saturday at the same time?

Show Name	Genre	Day	Start Time
Late Night Jazz	jazz	Friday	9:00 PM
Weekend Groove	jazz	Saturday	7:00 PM
Blues Hour	blues	Friday	8:00 PM
Sunday Sessions	jazz	Sunday	6:00 PM
Jazz Brunch	jazz	Saturday	11:00 AM

▮ Green rows = expected matches for this goal

Variables: genre = genre (string) • day = day of week (string)

A student wants to count shows that are a jazz show AND take place on Friday OR Saturday. Which expression evaluates to true for shows that should be counted?

Boundary Value — < vs. ≤

HardBoolean Filtering

⚠Watch for: “At least 4.0” includes 4.0 itself. Which operator includes the boundary?

Product	Category	Rating	In Stock
Wireless Speaker	electronics	4.5	true
Desk Lamp	electronics	3.5	true
Yoga Mat	fitness	4.5	true
USB Hub	electronics	4.0	false
Phone Stand	electronics	4.0	true

▮ Green rows = expected matches for this goal

Variables: cat = category (string) • rating = average rating (number) • inStock = availability (boolean)

A student wants to count electronics products that have a rating of at least 4.0 and are currently in stock. Which expression evaluates to true for products that should be counted?

Multi-Value Field — The Impossible AND

HardBoolean Filtering

⚠Watch for: A customer has exactly ONE membership value. Can it ever equal both “gold” AND “platinum” at the same time?

Customer ID	Status	Membership	Orders
C001	active	gold	8
C002	active	platinum	12
C003	inactive	gold	3
C004	active	silver	6
C005	active	gold	5

▮ Green rows = expected matches for this goal

Variables: status = account status (string) • membership = membership tier (string)

A student wants to count customers who are active and have either a gold or platinum membership. Which expression evaluates to true for customers that should be counted?

Section 2: Filter & Sort Ordering

Which sequence of filter and sort steps puts the target row at position 1?

Before revealing choices: Trace each sequence on the table above. Ask two questions: (1) Does the sequence use the correct sort key (e.g., sort by age to find youngest — not by name)? (2) After all steps complete, which row is first? The green rows in the table show the expected matches.

Which Sequences Find the Right Row?

HardFilter / Sort Ordering

Goal: find the youngest Marketing employee. Unknown ages are stored as 0 and should be ignored. The target employee must appear in row 1 when complete.

Name	Dept	Age	Notes
Chen, M.	Marketing	28
Davis, T.	Marketing	0	unknown age
Adams, R.	Sales	24
Brown, K.	Marketing	35
Foster, L.	Marketing	42

▮ Green rows = expected matches for this goal

Available Actions

Filter by departmentRemove entries where dept ≠ Marketing

Filter unknown ageRemove entries where age = 0

Sort by ageSort from least to greatest age

Sort by nameSort alphabetically by last name

Trace Each Sequence First

Seq I

Filter dept

Filter age=0

Sort age ASC

Row 1 = Chen (28) ✓

Seq II

Filter age=0

Sort age ASC

Filter dept

Row 1 = Chen (28) ✓

Seq III

Filter dept

Sort name A-Z

Filter age=0

Row 1 = Brown (35) ✗

Seq IV

Sort age ASC

Filter dept

Filter age=0

Row 1 = Chen (28) ✓

Note: Applying a filter does not change the relative order of remaining rows.

I. Filter by department → Filter unknown age → Sort by age

II. Filter unknown age → Sort by age → Filter by department

III. Filter by department → Sort by name → Filter unknown age

IV. Sort by age → Filter by department → Filter unknown age

Which of the sequences correctly places the youngest Marketing employee in row 1?

Select Two — Which Orderings Work?

HardFilter / Sort Ordering — Select Two

⚠Watch for: Which sort direction puts the most expensive item at row 1?

Goal: find the most expensive available furniture item with a listed price. Items with no price are stored as -1 and should be ignored. The target must appear in row 1.

Product	Category	Price ($)	Available
Bookshelf	furniture	499	true
Side Table	furniture	-1	true
Laptop	electronics	999	true
Coffee Table	furniture	299	true
Wardrobe	furniture	599	false

▮ Green rows = expected matches for this goal

Available Actions

Filter by categoryRemove entries where category ≠ furniture

Filter unknown priceRemove entries where price = -1

Filter availableRemove entries where available = false

Sort price descendingSort greatest to least price

Sort price ascendingSort least to greatest price

Trace Each Sequence First

Seq A

Filter cat

Filter avail

Filter price=-1

Sort DESC

Row 1 = Bookshelf $499 ✓

Seq B

Filter price=-1

Filter avail

Sort DESC

Filter cat

Row 1 = Bookshelf $499 ✓

Seq C

Sort DESC

Filter cat

Filter avail

Filter price=-1

Row 1 = Bookshelf $499 ✓

Seq D

Filter cat

Filter price=-1

Sort ASC

Filter avail

Row 1 = Coffee Table $299 ✗

Note: Applying a filter does not change the relative order of remaining rows.

A. Filter category → Filter available → Filter unknown price → Sort price descending

B. Filter unknown price → Filter available → Sort price descending → Filter category

C. Sort price descending → Filter category → Filter available → Filter unknown price

D. Filter category → Filter unknown price → Sort price ascending → Filter available

Select two sequences that correctly place the most expensive available furniture item with a listed price in row 1.

ⓘ Select TWO answers.

I, II, III — Which Orderings Work?

HardFilter / Sort Ordering — I & II Format

⚠Watch for: Two sequences use the correct sort key. One uses the wrong sort key entirely.

Goal: find the oldest sci-fi novel with a known author and year. Unknown values are stored as “(unknown)” or -1. The target must appear in row 1.

Title	Author	Year	Genre
Dune	Herbert	1965	sci-fi
Unknown Novel	(unknown)	1998	mystery
Foundation	Asimov	1951	sci-fi
Neuromancer	Gibson	-1	sci-fi
Ender's Game	Card	1985	sci-fi

▮ Green rows = expected matches for this goal

Available Actions

Filter by genreRemove entries where genre ≠ sci-fi

Filter unknown authorRemove entries where author = “(unknown)”

Filter unknown yearRemove entries where year = -1

Sort by year ascendingSort oldest (smallest year) to newest

Sort by title A-ZSort alphabetically by title

Trace Each Sequence First

Seq I

Filter genre

Filter unknown author

Filter year=-1

Sort year ASC

Row 1 = Foundation 1951 ✓

Seq II

Filter year=-1

Filter genre

Sort year ASC

Filter unknown author

Row 1 = Foundation 1951 ✓

Seq III

Filter genre

Sort title A-Z

Filter unknown author

Filter year=-1

Row 1 = Dune 1965 ✗

Note: Applying a filter does not change the relative order of remaining rows.

I. Filter genre → Filter unknown author → Filter unknown year → Sort year ascending

II. Filter unknown year → Filter genre → Sort year ascending → Filter unknown author

III. Filter genre → Sort title A-Z → Filter unknown author → Filter unknown year

Which sequences correctly place the oldest sci-fi novel with a known author and year in row 1?

Section 3: Algorithm Step Ordering

Some steps depend on the output of other steps — they can’t run first.

Before revealing choices: Draw the dependency chain. Ask for each step: “What data does this step need as input? Has that data been created yet?” A step cannot run before the step that produces its required input.

Which Step Order Produces the Correct Result?

MediumAlgorithm Step Ordering

⚠Watch for: Which step must run first before any of the others make sense?

A programmer wants an algorithm that takes a list of email addresses and returns a sorted list of unique domain names (the part after the @).
Example: [“[email protected]”, “[email protected]”, “[email protected]”] → [“google.com”, “yahoo.com”].

Algorithm Steps

Extract: Extract the domain from each email (everything after the @)

Remove duplicates: Remove duplicate domain names from the list

Sort: Sort the domain names alphabetically

I. Extract → Remove duplicates → Sort

II. Extract → Sort → Remove duplicates

III. Remove duplicates → Extract → Sort

IV. Sort → Extract → Remove duplicates

Executing which of the following sequences will produce the correct sorted list of unique domain names?

Step Dependencies — What Needs What?

HardAlgorithm Step Ordering

⚠Watch for: Draw the dependency chain: which step’s output does each other step need as input?

A teacher wants an algorithm that identifies students who scored above the class average, then returns their names in alphabetical order.

Algorithm Steps

Step A: Calculate each student’s individual average score across all assignments

Step B: Compute the class average (mean of all individual averages from Step A)

Step C: Keep only students whose individual average > class average

Step D: Sort the remaining student names alphabetically

A
individual
averages→ needs A →B
class
average→ needs B →C
filter above
average→ needs C →D
sort
names

I. A → B → C → D

II. B → A → C → D

III. A → C → B → D

IV. A → B → D → C

Which sequence correctly produces an alphabetical list of students who scored above the class average?

When Does Convert Lock the Data?

HardAlgorithm Step Ordering

⚠Watch for: Once Convert runs, the data becomes a string. Can you still Sort or Filter a string the same way you sort a list of numbers?

A programmer wants an algorithm that takes a list of numbers and returns a formatted string of perfect squares in order, separated by commas.
Example: [16, 7, 4, 25, 3, 9] → “4, 9, 16, 25”

Algorithm Steps

Filter: Keep only numbers that are perfect squares (1, 4, 9, 16, 25, …)

Sort: Sort the remaining numbers from least to greatest

Convert: Join the list of numbers into a single comma-separated string

I. Filter → Sort → Convert

II. Sort → Filter → Convert

III. Filter → Convert → Sort

IV. Convert → Filter → Sort

Which of the following correctly identifies all sequences that produce the correct result?

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AP CSP Filtering Sorting Practice

AP CSP Filtering, Sorting & Boolean Expressions

Section 1: Boolean Expressions

Section 2: Filter & Sort Ordering

Section 3: Algorithm Step Ordering

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