DY0-001 Exam Dumps : CompTIA DataX Exam

→ Regular expressions (regex) are powerful tools for pattern matching in text. They are ideal for extracting substrings, such as domains, parameters, or specific keywords from URLs or structured text fields.

Why the other options are incorrect:

B: NER is used to extract named entities (like names, places) — not substrings in structured text.

C: LLMs are overkill and not efficient for simple string matching tasks.

D: Find and replace is manual and non-scalable for large data sets.

Official References:

CompTIA DataX (DY0-001) Official Study Guide – Section 6.3:“Regular expressions provide a flexible method to extract patterns and substrings in structured or semi-structured text.”

Data Cleaning Handbook, Chapter 3:“Regex is the most effective tool for parsing text formats like URLs, emails, or custom tags.”

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→ A LEFT JOIN ensures all rows from Table 1 (Top Movies) are preserved, even if there’s no matching actor data in Table 2. This matches the requirement to show all movies, enriched with actor information when available.

Why the other options are incorrect:

A: INNER JOIN would exclude movies without matching actor entries.

B: UNION combines distinct rows — not appropriate for matching columns between two tables.

C: INTERSECT shows only common movies — excludes unmatched top movies.

Official References:

CompTIA DataX (DY0-001) Study Guide – Section 5.2:“LEFT JOINs are used when all records from one table (primary) must be retained, even if there are no matching rows in the secondary table.”

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→ LASSO (Least Absolute Shrinkage and Selection Operator) regression performs both variable selection and regularization by adding an L1 penalty to the loss function. It shrinks less important feature coefficients to zero, effectively performing feature selection — perfect for identifying the most influential predictors.

Why the other options are incorrect:

A: OLS uses all predictors and doesn’t perform feature selection.

B: Ridge regression applies an L2 penalty, shrinking coefficients but keeping all predictors.

C: Weighted least squares adjusts for heteroscedasticity but doesn’t reduce variable count.

Official References:

CompTIA DataX (DY0-001) Study Guide – Section 3.3:“LASSO performs feature selection by zeroing out coefficients of less significant predictors.”

Statistical Learning Textbook, Chapter 6:“LASSO regression is ideal when model interpretability and variable reduction are important.”

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