2.11. DataFrame Export

  • File paths works also with DATAs

  • SQL functions uses SQLAlchemy, which supports many RDBMS

2.11.1. SetUp

>>> import pandas as pd
>>>
>>> df = pd.DataFrame()

2.11.2. Most Frequently Used

>>> 
... df.to_csv()
... df.to_dict()
... df.to_excel()
... df.to_json()
... df.to_sql()

2.11.3. Other

>>> 
... df.to_clipboard()
... df.to_dense()
... df.to_feather()
... df.to_gbq()
... df.to_hdf()
... df.to_html()
... df.to_latex()
... df.to_msgpack()
... df.to_numpy()
... df.to_parquet()
... df.to_period()
... df.to_pickle()
... df.to_records()
... df.to_sparse()
... df.to_stata()
... df.to_string()
... df.to_timestamp()
... df.to_xarray()

2.11.4. Assignments

Code 2.38. Solution
"""
* Assignment: DataFrame Export CSV
* Complexity: easy
* Lines of code: 3 lines
* Time: 5 min

English:
    2. Read data from `DATA` as `result: pd.DataFrame`
    3. While reading use `header=0` parameter
    4. Select 146 head rows, and last 11 from it
    5. Export data from column `Event` to file the `FILE`
    6. Data has to be in CSV format
    7. Run doctests - all must succeed

Polish:
    2. Wczytaj dane z `DATA` jako `result: pd.DataFrame`
    3. Przy wczytywaniu użyj parametru `header=0`
    4. Wybierz pierwszych 146 wierszy, a z nich ostatnie 11
    5. Wyeksportuj dane z kolumny `Event` do pliku `FILE`
    6. Dane mają być w formacie CSV
    7. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from os import remove

    >>> result = open(FILE).read()
    >>> remove(FILE)

    >>> assert result is not Ellipsis, \
    'Assign result to variable: `result`'
    >>> assert type(result) is str, \
    'Variable `result` has invalid type, should be `str`'

    >>> print(result)  # doctest: +NORMALIZE_WHITESPACE
    ,Event
    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.
    <BLANKLINE>

"""

import pandas as pd

DATA = 'https://python3.info/_static/apollo11.html'
FILE = r'_temporary.csv'


Code 2.39. Solution
"""
* Assignment: DataFrame Export JSON
* Complexity: easy
* Lines of code: 3 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 file the `FILE`
    5. Data has to be in JSON format
    6. 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 pliku `FILE`
    5. Dane mają być w formacie JSON
    6. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from os import remove
    >>> import json

    >>> result = open(FILE).read()
    >>> remove(FILE)

    >>> assert result is not Ellipsis, \
    'Assign result to variable: `result`'
    >>> assert type(result) is str, \
    'Variable `result` has invalid type, should be `str`'

    >>> json.loads(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."}

"""

import pandas as pd

DATA = 'https://python3.info/_static/apollo11.html'
FILE = r'_temporary.json'

# Dump DATA to FILE in JSON format
# type: pd.DataFrame
result = ...


Code 2.40. Solution
"""
* Assignment: DataFrame Export Pickle
* Complexity: easy
* Lines of code: 3 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 file the `FILE`
    5. Data has to be in Pickle format
    6. 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 pliku `FILE`
    5. Dane mają być w formacie Pickle
    6. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from os import remove
    >>> result = pd.read_pickle(FILE)
    >>> remove(FILE)

    >>> pd.set_option('display.width', 500)
    >>> pd.set_option('display.max_columns', 10)
    >>> pd.set_option('display.max_rows', 20)

    >>> assert result is not Ellipsis, \
    'Assign result to variable: `result`'
    >>> assert type(result) is pd.Series, \
    'Variable `result` has invalid type, should be `pd.Series`'

    >>> result
    135                                    LM lunar landing.
    136                   LM powered descent  engine cutoff.
    137    Decision made to  proceed with EVA prior to fi...
    138                        Preparation for EVA  started.
    139                           EVA started (hatch  open).
    140                 CDR completely outside  LM on porch.
    141    Modular equipment  stowage assembly deployed (...
    142                    First clear TV picture  received.
    143    CDR at foot of ladder (starts to report, then ...
    144    CDR at foot of ladder and described surface as...
    145    1st step taken lunar surface (CDR). That's one...
    Name: Event, dtype: object
"""

import pandas as pd

DATA = 'https://python3.info/_static/apollo11.html'
FILE = r'_temporary.pkl'

# Dump DATA to FILE in Pickle format
# type: pd.DataFrame
result = ...

Code 2.41. Solution
"""
* Assignment: DataFrame Export SQL
* Complexity: easy
* Lines of code: 4 lines
* Time: 5 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')
    >>> remove(FILE)

    >>> 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.")]

"""

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 = ...