DOC: Add doc-string examples for pd.read_sql using custom parse_dates arg values #38475
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pandas/io/sql.py
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| -------- | ||
| Read data from SQL via either a SQL tablename or a SQL query | ||
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| >>> pd.read_sql('table_name', 'postgres:///db_name') # doctest:+SKIP |
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Maybe the examples can demonstrate connecting to a sqlite db so we don't have to skip all these doctests
pandas/io/sql.py
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| ... 'postgres:///db_name', | ||
| ... parse_dates=["date_column"]) # doctest:+SKIP | ||
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| The "parse_dates" argument calls pd.to_datetime on the provided columns. Custom |
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Double backticks around pd.to_datetime
pandas/io/sql.py
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| >>> pd.read_sql('SELECT * FROM table_name', 'postgres:///db_name') # doctest:+SKIP | ||
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| Apply dateparsing to columns through the "parse_dates" argument |
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Double backticks around parse_dates instead
avinashpancham
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Added doctests pass. CI fails due to other reasons, since I only added documentation. Will merge master later to run CI agian. |
pandas/io/sql.py
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| Read data from SQL via either a SQL query or a SQL tablename (latter not | ||
| possible for SQLite tables) | ||
| >>> from sqlite3 import connect | ||
| >>> conn = connect('file.db') |
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You can use ":memory:" instead
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Cool, didn't know this! Changed it.
pandas/io/sql.py
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| Examples | ||
| -------- | ||
| Read data from SQL via either a SQL query or a SQL tablename (latter not | ||
| possible for SQLite tables) |
pandas/io/sql.py
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| >>> pd.read_sql('test_data', 'postgres:///db_name') # doctest:+SKIP | ||
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| Apply dateparsing to columns through the ``parse_dates`` argument |
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date parsing (and elsewhere)
pandas/io/sql.py
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| >>> pd.read_sql('SELECT int_column, date_column FROM test_data', | ||
| ... conn, | ||
| ... parse_dates=["date_column"]) | ||
| int_column date_column |
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These column names looks offset
pandas/io/sql.py
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| >>> pd.read_sql('SELECT int_column, date_column FROM test_data', | ||
| ... conn, | ||
| ... parse_dates={"date_column": {"errors": "ignore"}}) | ||
| int_column date_column |
pandas/io/sql.py
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| >>> pd.read_sql('SELECT int_column, date_column FROM test_data', | ||
| ... conn, | ||
| ... parse_dates={"date_column": {"format": "%d/%m/%y"}}) | ||
| int_column date_column |
pandas/io/sql.py
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| Examples | ||
| -------- | ||
| Read data from SQL via either a SQL query or a SQL tablename (latter not | ||
| possible for SQLite tables) |
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I would assume parse_dates should still work for sqlite.
Our docs state
Dict of {column_name: arg dict}, where the arg dict corresponds to the keyword arguments of pandas.to_datetime() Especially useful with databases without native Datetime support, such as SQLite.
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Sorry, I will clarify this. What I mean is that SQLite only accepts queries not just table names:
pd.read_sql('SELECT * FROM test_data', conn) # works for SQLite
pd.read_sql('test_data', conn) # does not work for SQLite
# pandas.io.sql.DatabaseError: Execution failed on sql 'test_data': near "test_data": syntax errorThere was a problem hiding this comment.
Made explanation more explicit
avinashpancham
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very nice @avinashpancham |
follow on PR for #37823
black pandasgit diff upstream/master -u -- "*.py" | flake8 --diff