Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 3-minute battle to put them to the test.
Filter by type
Filter by difficulty
Popular topics
1,575 challenges matching your filters
- Code AnalysisIntermediate
ABC enforcement
pythonintermediate - Code AnalysisIntermediate
__call__ usage
pythonintermediate - Code AnalysisIntermediate
dataclass frozen
pythonintermediate - Code AnalysisIntermediate
dunder getitem (Analysis)
pythonintermediate - Code AnalysisIntermediate
MRO for Mixin
pythonintermediate - Code AnalysisIntermediate
classmethod trace
pythonintermediate - Code AnalysisIntermediate
timeit usage
pythonintermediate - Code AnalysisIntermediate
lru_cache hit
pythonintermediate - Code AnalysisBeginner
generator sum
pythonbeginner - Code AnalysisIntermediate
set vs list membership
pythonintermediate - Code AnalysisBeginner
deque appendleft
pythonbeginner - Code AnalysisBeginner
__name__ check
pythonbeginner - Code AnalysisBeginner
Module alias
pythonbeginner - Code AnalysisBeginner
from import — Namespace Pollution
pythonbeginner - Code AnalysisBeginner
sys.path existence
pythonbeginner - Code AnalysisIntermediate
__all__ effect
pythonintermediate - Code AnalysisBeginner
wildcard import
pythonbeginner - Code AnalysisIntermediate
sys.modules check
pythonintermediate - Code AnalysisIntermediate
eval injection
pythonintermediate - Code AnalysisIntermediate
shell injection
pythonintermediate - Code AnalysisIntermediate
path traversal (Analysis)
pythonintermediate - Code AnalysisBeginner
datetime format
pythonbeginner - Code AnalysisBeginner
timedelta calc
pythonbeginner - Code AnalysisIntermediate
random seed
pythonintermediate - Code AnalysisBeginner
math.ceil
pythonbeginner - Code AnalysisIntermediate
enum iteration
pythonintermediate - Code AnalysisHard
typing Union
pythonhard - Code AnalysisIntermediate
itertools.islice
pythonintermediate - Code AnalysisBeginner
statistics mean
pythonbeginner - Code AnalysisIntermediate
logging basicConfig
pythonintermediate - Code AnalysisHard
Literal type
pythonhard - Code AnalysisBeginner
String Slicing Step
pythonbeginner - Code AnalysisBeginner
String Format Nesting
pythonbeginner - Code AnalysisBeginner
join with numbers
pythonbeginner - Code AnalysisBeginner
split and join
pythonbeginner - Code AnalysisBeginner
String Immutability
pythonbeginner - Code AnalysisIntermediate
re.search
pythonintermediate - Code AnalysisIntermediate
encode decode
pythonintermediate - Code AnalysisBeginner
f-string number format
pythonbeginner - Code AnalysisIntermediate
partition example
pythonintermediate - Code AnalysisBeginner
List Append Output
pythonbeginner - Code AnalysisBeginner
String Slicing
pythonbeginner - Code AnalysisBeginner
Range with Step
pythonbeginner - Code AnalysisBeginner
String Format
pythonbeginner - Code AnalysisIntermediate
Default Arg Trap
pythonintermediate - Code AnalysisBeginner
Multiple Assignment — Star Unpacking
pythonbeginner - Code AnalysisIntermediate
Identity Check
pythonintermediate - Code AnalysisBeginner
Comparison Chaining
pythonbeginner - Code AnalysisIntermediate
Boolean Short-Circuit
pythonintermediate - Code AnalysisIntermediate
Walrus in Expression
pythonintermediate - Code AnalysisIntermediate
for/else Trigger
pythonintermediate - Code AnalysisIntermediate
pytest parametrize (Analysis)
pythonintermediate - Code AnalysisBeginner
mock return_value
pythonbeginner - Code AnalysisBeginner
assertEqual output
pythonbeginner - Code AnalysisIntermediate
assertRaises context
pythonintermediate - Code AnalysisIntermediate
patch decorator
pythonintermediate - Code AnalysisIntermediate
doctest example
pythonintermediate - Code AnalysisIntermediate
MagicMock attributes
pythonintermediate - Code AnalysisHard
Class Variable Shadow
code-analysisPythonlanguage - Code AnalysisHard
Decorator Order
code-analysisPythonlanguage
Practice now, dominate the arena
Every challenge here is drawn from the live Code Royale pool. Review a question, then head to the arena to answer under pressure against a real opponent — 3-minute matches, Elo ranking, and badge tiers on the line.