Quick Answer
The answer is the `isalpha()` method, which returns `True` when every character in the string is a letter. This method checks specifically for alphabetic characters—both uppercase and lowercase—and excludes digits, spaces, punctuation, or any other non-letter symbols. In contrast, `isalnum()` would also allow digits, `isdigit()` only matches numeric characters, and `isspace()` only whitespace, making `isalpha()` the precise tool for this task. On the Certified Associate Python Programmer PCAP exam, this question tests your understanding of Python’s string classification methods, a common topic in the “Strings” domain. A frequent trap is confusing `isalpha()` with `isalnum()` when the requirement is strictly letters only; remember that “alpha” means letters alone, while “alnum” adds numbers. For a quick memory tip, think of “alpha” as the first letter of the alphabet—pure letters, nothing else.
This PCAP practice question tests your understanding of strings. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer wants to check if a string contains only alphabetic characters. Which string method should be used?
isalnum()
Why wrong: Incorrect: Allows digits as well.
isspace()
Why wrong: Incorrect: Only checks for whitespace characters.
isalpha()
Correct: Returns True if all characters are alphabetic.
isdigit()
Why wrong: Incorrect: Only checks for digits.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
isalpha()
The isalpha() method returns True if all characters in the string are letters. isalnum() allows digits, isdigit() only digits, and isspace() only whitespace.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
isalnum()
Why it's wrong here
Incorrect: Allows digits as well.
isspace()
Why it's wrong here
Incorrect: Only checks for whitespace characters.
isalpha()
Why this is correct
Correct: Returns True if all characters are alphabetic.
Related concept
Read the scenario before looking for a memorised answer.
isdigit()
Why it's wrong here
Incorrect: Only checks for digits.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Identify which PCAP exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Strings — This question tests Strings — Read the scenario before looking for a memorised answer..
The correct answer is: isalpha() — The isalpha() method returns True if all characters in the string are letters. isalnum() allows digits, isdigit() only digits, and isspace() only whitespace.
Identify which PCAP exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This PCAP practice question is part of Courseiva's free Python Institute certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCAP exam.
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