Regular Expressions GPYC Practice Questions (Page 2)

Questions 6–10

1. 6foundation · easy

   What is the primary benefit of using re.compile() before performing multiple searches with the same pattern?

   • AIt automatically applies all regex flags to the pattern.
   • BIt makes the pattern match only at the beginning of the string.
   • CIt improves performance by reusing the compiled pattern object.
   • DIt converts the pattern to a raw string.
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2. 7expert · medium

   A developer is using a regex to parse a large log file. The pattern r'\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}' is used to match timestamps. The log file has millions of lines, and the script is running slowly. Which optimization is most likely to improve performance?

   • ACompile the pattern with re.compile
   • BUse a non-capturing group for the date and time
   • CUse re.match instead of re.search
   • DUse a character class instead of \d
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4. 8application · medium

   A developer is using re.sub to replace all occurrences of a pattern in a string. The pattern is r'<.*>' and the replacement is 'X'. The input is '<a> <b> <c>'. What will be the output?

   • AX
   • BX X X
   • CX <b> X
   • D<a> X <c>
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5. 9expert · hard

   A security tool is using the pattern `^(a+)+$` to validate usernames. On a long string of 'a' characters followed by '!', the tool hangs. What is the most effective fix?

   • AIncrease the regex engine's recursion limit
   • BAdd re.DOTALL flag
   • CChange the pattern to `^a+$`
   • DUse a lazy quantifier: `^(a+?)+$`
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6. 10foundation · easy

   What is the difference between the greedy quantifier '.*' and the lazy quantifier '.*?'?

   • AGreedy matches only at the start; lazy matches anywhere.
   • BGreedy is faster; lazy is slower.
   • CGreedy matches one or more; lazy matches zero or more.
   • DGreedy matches as much as possible; lazy matches as little as possible.
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