Chapter 1 · Section 3 practice

Selection and Index Alignment

0 of 4 answered

These questions review the examples in the companion slides. Choose an answer, then check the explanation.

Question 1

How many rows do aep.loc[“2017-01-01 01:00”:“2017-01-01 05:00”] and aep.iloc[0:5] return?

  • 4 and 5
  • 5 and 5
  • 5 and 4
  • 4 and 4

Question 2

For jan = sp500.loc[“2020”], do jan.loc[“2020-01-06”:“2020-01-08”] and jan.iloc[2:5] return the same rows?

  • Yes — Jan 6, 7, 8 both times, but for opposite slicing rules
  • No — .loc gives 2 rows, .iloc gives 3
  • No — .iloc includes Jan 9
  • They raise — you cannot mix index value and position

Question 3

r.loc[r > 0.02 & r < 0.05] …

  • Works — same as the parenthesised version
  • Returns an empty Series
  • Raises TypeError — & binds tighter than >
  • Returns the days above 2 % only

Question 4

price.sample(500, replace=True, random_state=0) …

  • Always returns the first 500 rows
  • Returns 500 distinct rows
  • May contain the same product twice
  • Raises unless frac is given