How does pandas calculate quartiles?
问题 I have a very simple dataframe: df = pd.DataFrame([5,7,10,15,19,21,21,22,22,23,23,23,23,23,24,24,24,24,25], columns=['val']) df.median() = 23 which is right because from 19 values in the list, 23 is 10th value (9 values before 23, and 9 values after 23) I tried to calculate 1st and 3rt quartile as: df.quantile([.25, .75]) val 0.25 20.0 0.75 23.5 I would have expected that from 9 values bellow median that 1st quartile should be 19, but as you can see above, python says it is 20. Similarly, for