v0.40: Create exercises. Challenge the community.

is_subsequence

Your mission

Implement is_subsequence, an ordered subsequence checker.

See it in action

is_subsequence("bot", "build output tree")

Expected result

True

Your checklist

For your own tracking. Tests grade your code.

Create hidden_subsequence.py.
Expose def is_subsequence(needle: str, haystack: str) -> bool:.
Return True when every character of needle can be found in haystack in the same order.
Characters do not need to be adjacent.
The comparison is case-sensitive.
An empty needle is always a valid subsequence.

More examples

is_subsequence("bto", "build output tree")

Expected result

False

Constraints

Expected files

hidden_subsequence.py

Allowed functions

None. Write every helper yourself.

is_subsequence

Your mission

Implement is_subsequence, an ordered subsequence checker.

See it in action

is_subsequence("bot", "build output tree")

Expected result

True

Your checklist

For your own tracking. Tests grade your code.

Create hidden_subsequence.py.
Expose def is_subsequence(needle: str, haystack: str) -> bool:.
Return True when every character of needle can be found in haystack in the same order.
Characters do not need to be adjacent.
The comparison is case-sensitive.
An empty needle is always a valid subsequence.

More examples

is_subsequence("bto", "build output tree")

Expected result

False

Constraints

Expected files

hidden_subsequence.py

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01Ordered characters foundWaiting

02Wrong orderWaiting

03Empty needleWaiting

04Missing tail characterWaiting

05Not enough repeated charactersWaiting

06Repeated charactersWaiting

07Case-sensitive comparisonWaiting

is_subsequence

Your mission

Implement is_subsequence, an ordered subsequence checker.

See it in action

is_subsequence("bot", "build output tree")

Expected result

True

Your checklist

For your own tracking. Tests grade your code.

Create hidden_subsequence.py.
Expose def is_subsequence(needle: str, haystack: str) -> bool:.
Return True when every character of needle can be found in haystack in the same order.
Characters do not need to be adjacent.
The comparison is case-sensitive.
An empty needle is always a valid subsequence.

More examples

is_subsequence("bto", "build output tree")

Expected result

False

Constraints

Expected files

hidden_subsequence.py

Allowed functions

None. Write every helper yourself.

v0.40: Create exercises. Challenge the community.

Meet Studio →

is_subsequence

Your mission

Implement is_subsequence, an ordered subsequence checker.

See it in action

is_subsequence("bot", "build output tree")

Expected result

True

Your checklist

For your own tracking. Tests grade your code.

Create hidden_subsequence.py.
Expose def is_subsequence(needle: str, haystack: str) -> bool:.
Return True when every character of needle can be found in haystack in the same order.
Characters do not need to be adjacent.
The comparison is case-sensitive.
An empty needle is always a valid subsequence.

More examples

is_subsequence("bto", "build output tree")

Expected result

False

Constraints

Expected files

hidden_subsequence.py

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01Ordered characters foundWaiting

02Wrong orderWaiting

03Empty needleWaiting

04Missing tail characterWaiting

05Not enough repeated charactersWaiting

06Repeated charactersWaiting

07Case-sensitive comparisonWaiting