Write_header argument specifies whether to include the field names in theĭelimited file. The source argument is the path of the delimited file, and the optional tocsv ( table1, 'example.csv' ) > # look what it did. tocsv ( table, source=None, encoding=None, errors='strict', write_header=True, **csvargs ) ¶ Note that all data values are strings, and any intended numeric values will So, e.g., to override theĭelimiter from the default CSV dialect, provide the delimiter keyword The source argument is the path of the delimited file, all other keywordĪrguments are passed to csv.reader(). > # now demonstrate the use of fromcsv(). ] > with open ( 'example.csv', 'w' ) as f. > import petl as etl > import csv > # set up a CSV file to demonstrate with. Once and so will not work as expected with data from stdin. Petl functions do access the underlying data source more than Session then this may not be a problem, however note that some Sure that data will only be read once in your script or interactive Subprocess, see the section on Python I/O streams below for moreīe aware that loading data from stdin breaks the table containerĬonvention, because data can usually only be read once.
#Read db text zip#
Some helper classes are also available for reading from other types ofįile-like sources, e.g., reading data from a Zip file, a string or a any other string - read directly from file.bz2 - read from file via bz2 decompression bgz - read from file via gzip decompression string starting with or ftp:// - read from URL.Source argument provides information about where to extract the For everything except petl.io.db.fromdb() the Number of rows to include in each chunk.The “from…” functions extract a table from a file-like source orĭatabase. If specified, return an iterator where chunksize is the List of column names to select from SQL table (only used when reading To the keyword arguments of pandas.to_datetime()Įspecially useful with databases without native Datetime support, for psycopg2, uses %(name)s so use params=, where the arg dict corresponds
#Read db text driver#
Check yourĭatabase driver documentation for which of the five syntax styles,ĭescribed in PEP 249’s paramstyle, is supported.Įg. To pass parameters is database driver dependent. List of parameters to pass to execute method. params list, tuple or dict, optional, default: None coerce_float bool, default TrueĪttempts to convert values of non-string, non-numeric objects (likeĭecimal.Decimal) to floating point, useful for SQL result sets. index_col str or list of str, optional, default: NoneĬolumn(s) to set as index(MultiIndex). The user is responsibleįor engine disposal and connection closure for the SQLAlchemy connectable strĬonnections are closed automatically. If a DBAPI2 object, only sqlite3 is supported. Using SQLAlchemy makes it possible to use any DB supported by that con SQLAlchemy connectable, str, or sqlite3 connection SQL query to be executed or a table name. Parameters sql str or SQLAlchemy Selectable (select or text object) Have more specific notes about their functionality not listed here. Will be routed to read_sql_query, while a database table name willīe routed to read_sql_table. To the specific function depending on the provided input. Read_sql_query (for backward compatibility). This function is a convenience wrapper around read_sql_table and Read SQL query or database table into a DataFrame. read_sql ( sql, con, index_col = None, coerce_float = True, params = None, parse_dates = None, columns = None, chunksize = None ) ¶