Data Science with Python Certification Data Analysis with Python 3

Question 1

When reading a CSV with pd.read_csv(), which parameter skips the first two rows of data?

Accepted Answer

skiprows=2

Answer

skiprows accepts an integer or list of row indices to skip before parsing the file.

Question 2

What does np.where(condition, x, y) return?

Accepted Answer

An array with x where condition is True, else y

Answer

np.where with three arguments acts as a vectorized ternary operator, selecting from x or y element-wise.

Question 3

Which pandas method reshapes data from wide format to long format?

Accepted Answer

df.melt()

Answer

df.melt() unpivots a DataFrame from wide to long format, making column headers into values.

Question 4

A DataFrame has a MultiIndex. Which method converts the index levels back to regular columns?

Accepted Answer

df.reset_index()

Answer

reset_index() moves all or specified index levels into DataFrame columns and resets to a default integer index.

Question 5

What is the purpose of pd.cut() in data analysis?

Accepted Answer

Bins continuous data into discrete intervals

Answer

pd.cut() segments and sorts continuous values into bins, returning a Categorical object.

Data Science with Python Certification Practice Test