strup — API

strup is a package for unpacking basic data objects from a text string.

strup is written by Jens B. Helmers (c) 2020

SPDX-License-Identifier: MIT

The function unpack

strup.unpack(fmt, text, *args, **kwargs)

Extract basic data types from text based on fmt.

Parameters

  • fmt (str) – fmt[i] defines the type of item i in the output tuple. fmt[i] must be ‘i’, ‘f’, ‘s’, ‘?’ or ‘.’. Item i will be ignored if fmt[i]==’.’.

  • text (str) – The text string to extract the objects from

Other Parameters

  • *args (list, optional) – Additional variable length argument list to be submitted to the constructor of Unpack

  • **kwargs (dict, optional) – Additional keyword arguments to be submitted to the constructor of Unpack

Returns

The tuple of objects parsed from text.

Return type

tuple

Raises

ValueError – If any parsing error occur.

Examples

>>> unpack("ifs?", "5 2.3   ole  True")
(5, 2.3, 'ole', True)
>>> unpack("isf", "100 'Donald Duck' 125.6", quote="'")
(100, 'Donald Duck', 125.6)

The class Unpack

class strup.Unpack(fmt, sep=None, none=False, quote=None, quote_escape=None)

Unpack is a Python package for unpacking basic data types from a text string.

Each item is of type ‘int’, ‘float’, ‘string’ or ‘bool’ depending on a format code in the constructor.

__init__(fmt, sep=None, none=False, quote=None, quote_escape=None)

Constructor for Unpack.

Parameters

  • fmt (str) – fmt[i] defines the type of item i in the output tuple. fmt[i] must be ‘i’, ‘f’, ‘s’, ‘?’ or ‘.’. Item i will be ignored if fmt[i]==’.’.

  • sep (str or None, optional) – String to separate items. See string.split() method.

  • none (bool, optional) – If True: Zero-sized items are interpreted as None.

  • quote (str or None, optional) – String items are sometimes enclosed by quote characters. Quotes are mandatory if string items includes the sep or quote characters. A quote character inside an item must be escaped by ‘quote_escape’. (See example below). It is not possible to apply quotes if quote==’‘.

  • quote_escape (str or None, optional) – Typical values are ‘”“’, “’‘”, r’”’ or “’”. quote_escape = None is interpreted as quote_escape = quote*2

Raises

ValueError – If any parsing error occur.

Examples

See the __call__() examples for application of these decoders:

>>> decode1 = Unpack('ifssis')
>>> decode2 = Unpack('.fs', sep=',')
>>> decode3 = Unpack('isfs', sep=' ', quote='"', quote_escape='""')
__call__(text)

Extract the tuple of objects by parsing text based on self._fmt

Parameters

text (str) – The text string to extract the objects from

Returns

The tuple of objects parsed from text.

Return type

tuple

Raises

ValueError – If any parsing error occur.

Examples

decode1, decode2 and decode3 as defined in the __init__() examples:

>>> decode1("3 4.5  ole dole 5 doffen")
(3, 4.5, 'ole', 'dole', 5, 'doffen')
>>> decode2("3,4.5,  ole,dole,5,doffen")
(4.5, '  ole')
>>> decode3('3 "A ""quote"" test" 93.4 knut ignored')
(3, 'A "quote" test', 93.4, 'knut')