Puzzle 25 Hit and Run

Pandas Brain Teasers — by Miki Tebeka (33 / 34)

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hits.py

​ ​import​ ​sqlite3​
​ ​import​ ​pandas​ ​as​ ​pd​
​ 
​ conn = sqlite3.connect(​':memory:'​)
​ conn.executescript(​'''​
​ ​CREATE TABLE visits (day DATE, hits INTEGER);​
​ ​INSERT INTO visits VALUES​
​ ​    ('2020-07-01', 300),​
​ ​    ('2020-07-02', 500),​
​ ​    ('2020-07-03', 900);​
​ ​'''​)
​ 
​ df = pd.read_sql(​'SELECT * FROM visits'​, conn)
​ ​print​(​'time span:'​, df[​'day'​].max() - df[​'day'​].min())

Guess the Output

IMPORTANT

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

This code will raise a TypeError.

I love SQLite3. It’s a great single-file database that I’ve used many times to transfer data. It is widely used and heavily tested and can handle vast amounts of data (currently about 140 terabytes).

However, you need to know how to work with it.

In the teaser code, we create a hits table that has two columns: