ljson.convert package¶

Submodules¶

ljson.convert.csv module¶

Convert csv to ljson and the ohter way around.

ljson.convert.csv.csv2file(fin, fout, types=None, modifiers=None, fieldnames=None, restkey=None, restval=None, dialect='excel', **fmtargs)[source]¶

Converts the csv file to a ljson file. Reads csv from fin and writes to fout.

The main difference to csv2table is that csv2file uses the on-disk implementation.

This function should be used if one wants to convert just the files without using the data.

See also: csv2table

Returns: the table

ljson.convert.csv.csv2table(fin, types=None, modifiers=None, fieldnames=None, restkey=None, restval=None, dialect='excel', **fmtargs)[source]¶

Reads the csv table from fin and converts it to a ljson.base.memTable.

The arguments fin,fieldnames,restkey,restval,dialect,fmtargs are passed to csv.DictReader.

types is a dict containing the types of the columns, they are mapped {<columname>:<typename>}.

modifiers is a dict containing the modifiers mapped {<columname>:[<modifier>, <modifier>]}.

If a column does not have an expicite type "str" is used.

Eg:

>>> from io import StringIO
>>> fin = StringIO("id,name\n1,foo\n2,bar\n3,baz")
>>> table = csv2table(fin, types = {"id": "int", "name":"str"}, modifiers = {"id": ["unique"]})
>>> list(table)
[{'name': 'foo', 'id': 1}, {'name': 'bar', 'id': 2}, {'name': 'baz', 'id': 3}]

Note: to convert files csv2file should be used.

Returns: the table

ljson.convert.csv.table2csv(table, fout, restval='', extrasaction='raise', dialect='excel', *args, **kwds)[source]¶

Convert the given ljson table to csv.

The arguments restval='', extrasaction='raise', dialect='excel', *args, **kwds are passed to csv.DictWriter.

Hint: Converting files can be done by using the on-disk implementation:

>>> from ljson.base.disk import Table
>>> from ljson.convert.csv import table2csv
>>> fin = open("test.lson", "r+")
>>> table = Table.from_file(fin)
>>> fout = open("test.csv", "w")
>>> table2csv(table, fout)

Returns: None

ljson.convert.sql module¶

This module provides functions to convert ljson tables from/to SQL tables.

WARNING: The SQL datatype “BINARY” and the python datatype “bytes” might not work.

Note: If one wants to use json items, these items will be stored as “varchar” in SQL. The function table2sql will convert json automatically to str, but the “sql2*” functions will not convert str to json. One can convert the objects later.

ljson.convert.sql.sql2file(db, username, password, tablename, fout, host='localhost')[source]¶

Convert the SQL table to an ljson.disk.Table.

This function should be used to read big tables.

*WARNING*: fout must be opened in w+ mode!

See also: sql2table

Returns the resulting table.

ljson.convert.sql.sql2table(db, username, password, tablename, host='localhost')[source]¶

Convert the SQL table to an ljson table. This function(just like sql2file) does not parse json items automatically.

db, username, password and host are used to log in.

See also: sql2file

Returns the resulting table.

ljson.convert.sql.table2sql(table, db, username, password, tablename, host='localhost')[source]¶

Insert the values from the given table into the already existing SQL table.

json items will be stored as str instances.

Module contents¶