Puzzle 15 Free-Range

Pandas Brain Teasers — by Miki Tebeka (23 / 34)

👈 A Tale of One City | TOC | Y3K 👉

loc.py

​ ​import​ ​pandas​ ​as​ ​pd​
​ 
​ df = pd.DataFrame([
​     [1, 1, 1],
​     [2, 2, 2],
​     [3, 3, 3],
​     [4, 4, 4],
​     [5, 5, 5],
​ 
​ ])
​ 
​ ​print​(len(df.loc[1:3]))

Guess the Output

IMPORTANT

Try to guess what the output is before moving to the next page.

This code will print: 3

Slices in Python are half-open ranges. You get values from the first index, up to but not including the last index:

​ In [1]: chars = [​'a'​, ​'b'​, ​'c'​, ​'d'​, ​'e'​]
​ In [2]: chars[1:3]
​ Out[2]: [​'b'​, ​'c'​]

And most of the time, Pandas words the same way:

​ In [3]: s = pd.Series(chars)
​ In [4]: s[1:3]
​ Out[4]:
​ 1    b
​ 2    c
​ dtype: object

There are three ways to slice a pandas.Series or a pandas.DataFrame:

• Using loc, which works by label
• Using iloc, which works by offset