tSQLike 1.1.2

Description:

tSQLike 1.1.2

tSQLike


SQL-like interface to tabular structured data

Description
tSQLike is a Python3 module that is written with a hope to make tabular data process easier using SQL-like primitives.
Notes
Not that early stage, but still in development: may contain bugs
Usage
from tsqlike import tsqlike

t1 = tsqlike.Table(data=[['h1', 'h2', 'h3', 'h4'],
['a', 'b', 'c', 'd'],
['b', 'c', 'd', 'd'],
['f', 'g', 'h', 'i']],
name='first')
t2 = tsqlike.Table().import_list_dicts(data=[{'h1': 1, 'h2': 2, 'h3': 3},
{'h1': 'd', 'h2': 'e', 'h3': 'f'}],
name='second')
t3 = t1.join(t2, on='first.h4 == second.h1').select('*').order_by('second.h2', direction=tsqlike.ORDER_BY_DEC)
t3.write_csv(dialect='unix')

"first.h1", "first.h2", "first.h3", "first.h4", "second.h1", "second.h2", "second.h3"
"b", "c", "d", "d", "d", "e", "f"
"a", "b", "c", "d", "d", "e", "f"

Installation
pip install tsqlike

Functionality
Table class
The main class of the module
Data processing methods



Name
Status
Description




join
☑
Join two Tables (self and table) on an expression *. Complex, but slow


join_lt
☑
Light, limited, fast and safe Join, that doesn't use eval()


select
☑
Select column(s) from the Table *


select_lt
☑
eval()-free version of select


order_by
☑
ORDER BY primitive of SQL SELECT to sort the Table by a column


group_by
☑
GROUP BY primitive of SQL SELECT to apply aggregate function on a column



Import methods



Name
Status
Description




import_dict_lists
☑
Import a dictionary of lists into Table object


import_list_dicts
☑
Import a list of horizontal arranged dictionaries into the Table


import_list_lists
☑
Import list(list_1(), list_n()) with optional first row as the header



Export methods



Name
Status
Description




export_dict_lists
☑
Export a dictionary of lists


export_list_dicts
☑
Export list of dictionaries


export_list_lists
☑
Export list(list_1(), list_n()) with optional first row as the header



Write methods



Name
Status
Description




write_csv
☑
Make CSV from the Table object and write it to a file or stdout


write_json
☑
Write JSON into file or STDOUT *


write_json_lt
☑
eval()-free version of Table.write_json


write_xml
☐
Write XML. NB: Do we need this?



Private methods



Name
Status
Description




_redimension
☑
Recalculate dimensions of the Table.table



EvalCtrl class
Controls what arguments are available to eval() function



Name
Status
Description




blacklisted
☑
Checks if there is any of the blacklised words in stanza


blacklist_add
☑
Add a new word into the black list


blacklist_remove
☑
Remove the word from the blacklist



Standalone functions



Name
Status
Description




open_file
☑
Open a file


close_file
☑
Close a file


read_json
☑
Read JSON file


read_csv
☑
Read CSV file


read_xml
☐
Read XML. NB: Do we need XML support?


str_to_type
☑
Convert a str to a proper type: int, float or bool



WARNING
Methods Table.join(on=), Table.select(where=) and Table.write_json(export_f=), use eval() function
to run specified expressions within the program. ANY expression, including one that is potentially DANGEROUS
from security point of view, can be passed as the values of the above arguments. It is your duty to ensure correctness
and safety of these arguments and EvalCtrl helps to block potentially dangerous function/method names.
Alternatively you can use Table.join_lt(), Table.select_lt() and Table.write_json(). They are significantly less
powerful, but do not use eval().
Contacts
If you have an idea, a question, or have found a problem, do not hesitate to open an issue or mail me directly:
Mikhail Zakharov [email protected]