The correct modification is to check `if '=' not in line: continue` before splitting. This fix directly addresses the core problem: when parsing a key=value file, lines without an equals sign—such as `#comment`—are still processed by the `.split('=')` method, which turns the entire line into a dictionary key with a value of `None`. By explicitly skipping lines that lack the separator, you filter out not only comment lines but any malformed entries, ensuring only valid key-value pairs populate the dictionary. On the Certified Entry-Level Python Programmer PCEP exam, this tests your understanding of string methods and conditional logic in file parsing, a common trap where students rely solely on `startswith('#')` and forget that comments without an `=` still get split. Remember the mnemonic: “No equals, no entry”—always check for the separator before you split.
PCEP Practice Question: Functions, Tuples, Dictionaries and Exceptions
This PCEP practice question tests your understanding of functions, tuples, dictionaries and exceptions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 team is building a configuration parser that reads a file containing key=value pairs. They use a dictionary to store the configuration. The parser function `load_config(filename)` opens the file, reads line by line, splits on '=', and populates a dictionary. Some lines have comments starting with '#'. The developer wants to ensure that the dictionary is not polluted with comment lines. They write: `if line.startswith('#'): continue`. However, after parsing, the dictionary contains an entry with key '#' because some lines have no '=' sign. For example, a line like `#comment` is being added as a key with value None. The developer wants to fix this. Which modification should be made?
Use `key, value = line.split('=', 1)` and catch ValueError if less than two parts.
Why wrong: Unpacking would raise ValueError if no '=', but catching it would skip the line. Actually this could work, but not the best because it relies on exception handling for control flow.
B
Strip the line of whitespace before checking for comments.
Why wrong: Stripping does not prevent lines without '='.
C
Check `if '=' not in line: continue` before splitting.
Explicitly skip lines without '='.
D
Replace `startswith('#')` with `line.lstrip().startswith('#')` and also skip empty lines.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check `if '=' not in line: continue` before splitting.
Option C is correct because the core issue is that lines without an '=' sign (like `#comment`) are still processed by the split, causing the entire line to become a key with no value. By explicitly checking `if '=' not in line: continue` before splitting, the developer ensures that only lines containing a key-value separator are added to the dictionary, effectively filtering out comment lines and any other malformed lines.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use `key, value = line.split('=', 1)` and catch ValueError if less than two parts.
Why it's wrong here
Unpacking would raise ValueError if no '=', but catching it would skip the line. Actually this could work, but not the best because it relies on exception handling for control flow.
✗
Strip the line of whitespace before checking for comments.
Why it's wrong here
Stripping does not prevent lines without '='.
✓
Check `if '=' not in line: continue` before splitting.
Why this is correct
Explicitly skip lines without '='.
Related concept
Read the scenario before looking for a memorised answer.
✗
Replace `startswith('#')` with `line.lstrip().startswith('#')` and also skip empty lines.
Why it's wrong here
Does not handle lines without '='.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Python Institute often tests the misconception that checking for a comment marker alone is sufficient, when the real issue is that any line without an '=' sign (including comments) will be incorrectly parsed as a key with no value.
Detailed technical explanation
How to think about this question
The `split()` method on a string returns a list; when no '=' is present, `line.split('=', 1)` returns a list with one element, which when unpacked into two variables raises a ValueError. In real-world config parsing, robust code often combines multiple checks: skipping empty lines, ignoring comments, and validating that exactly one '=' exists per line, often using `line.partition('=')` to safely handle missing separators without exceptions.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the PCEP exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Functions, Tuples, Dictionaries and Exceptions — This question tests Functions, Tuples, Dictionaries and Exceptions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Check `if '=' not in line: continue` before splitting. — Option C is correct because the core issue is that lines without an '=' sign (like `#comment`) are still processed by the split, causing the entire line to become a key with no value. By explicitly checking `if '=' not in line: continue` before splitting, the developer ensures that only lines containing a key-value separator are added to the dictionary, effectively filtering out comment lines and any other malformed lines.
What should I do if I get this PCEP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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