3.5. To SQL¶
File paths works also with DATAs
SQL functions uses SQLAlchemy, which supports many RDBMS
3.5.1. SetUp¶
>>> import pandas as pd
>>>
>>> df = pd.DataFrame()
3.5.2. Assignments¶
"""
* Assignment: DataFrame Export SQL
* Complexity: easy
* Lines of code: 4 lines
* Time: 3 min
English:
1. Read data from `DATA` as `result: pd.DataFrame`
2. While reading use `header=0` parameter
3. Select 146 head rows, and last 11 from it
4. Export data from column `Event` to database `FILE` to table `apollo11`
5. Run doctests - all must succeed
Polish:
1. Wczytaj dane z `DATA` jako `result: pd.DataFrame`
2. Przy wczytywaniu użyj parametru `header=0`
3. Wybierz pierwszych 146 wierszy, a z nich ostatnie 11
4. Wyeksportuj dane z kolumny `Event` do bazy danych `FILE` do tabeli `apollo11`
5. Uruchom doctesty - wszystkie muszą się powieść
Tests:
>>> import sys; sys.tracebacklimit = 0
>>> from os import remove
>>> db = sqlite3.connect(FILE)
>>> result = db.execute('SELECT * FROM apollo11')
>>> assert result is not Ellipsis, \
'Assign result to variable: `result`'
>>> list(result) # doctest: +NORMALIZE_WHITESPACE
[(135, 'LM lunar landing.'),
(136, 'LM powered descent engine cutoff.'),
(137, 'Decision made to proceed with EVA prior to first rest period.'),
(138, 'Preparation for EVA started.'),
(139, 'EVA started (hatch open).'),
(140, 'CDR completely outside LM on porch.'),
(141, 'Modular equipment stowage assembly deployed (CDR).'),
(142, 'First clear TV picture received.'),
(143, 'CDR at foot of ladder (starts to report, then pauses to listen).'),
(144, 'CDR at foot of ladder and described surface as almost like a powder.'),
(145, "1st step taken lunar surface (CDR). That's one small step for a man...one giant leap for mankind.")]
>>> db.close()
>>> remove(FILE)
"""
import sqlite3
import pandas as pd
DATA = 'https://python3.info/_static/apollo11.html'
FILE = r'_temporary.sqlite3'
# Dump DATA to FILE in SQLite3 format
# type: pd.DataFrame
result = ...