strbalance

This small Python library provides functionality to check whether brackets, quotation marks, tags etc. inside the string are balanced, i.e. whether each of them is opened and closed properly with respect to other punctuation.

Installation

Use the package manager pip to install strbalance:

pip install strbalance

Usage

If the punctuation in the string is not balanced, the result is an Unbalanced object, None otherwise:

import strbalance

balance = strbalance.Balance()
print(balance.is_unbalanced('{[]}[()]'))  # outputs None
print(balance.is_unbalanced('abc(def"gh"ijkl)'))  # outputs None

unbalanced = balance.is_unbalanced('abcdefgh(ijkl]mnopqrst')
print(unbalanced.unclosed, unbalanced.short_summary, 
        unbalanced.long_summary)  # outputs ( ...fgh(ijk... ...fgh(ijkl]mno...
print(unbalanced.opening_position, unbalanced.opening_length,
        unbalanced.closing_position, unbalanced.closing_length)  # outputs 8 1 13 1

Istead of

import strbalance
balance = strbalance.Balance()
balance.is_unbalanced('{[]}[()]')

one can simply write

import strbalance
strbalance.is_unbalanced('{[]}[()]')

Apart from the string to check, strbalance.is_unbalanced() accepts all the optional parameters which can be passed to Balance constructor:

• pairs and symmetrical are lists of additional characters (or lines) to match; they default to None:

  • pairs – a list containing pairs of strings in the following format:

    [['a-opening'], ['a-closing'], ['b-opening', 'b-closing'] ...]

  • symmetrical – a list of strings representing characters (or their sequences) which have identical opening and closing forms.

• All other parameters are boolean and default to False:
  • tags – match HTML (XML) paired tags (case sensitive).
  • ignore_case – ignore case in tags.
  • cjk – include CJK brackets and quotation signs: ｢…｣, 「…」, 〈…〉, 《…》, 『…』, （…）, ［…］, ＜…＞, ｛…｝, ｟…｠, 【…】, 〔…〕, 〖…〗, 〘…〙, 〚…〛.
  • straight – include straight quotation marks (single and double).
  • custom - balance only custom characters and character sequences (listed in pairs and symmetrical and/or added with other parameters).
  • german - use German quoting convention: „…“, ‚…‘, »…«, ›…‹ instead of “…”, ‘…’, «…», ‹…›.
  • math - match parentheses with brackets in order to include mathematical [a,c) notation.

The pairs of characters matched by default:

• (…) parentheses
• […] brackets
• {…} braces
• “…” double quotes
• ‘…’ single quotes
• «…» double angle quotes
• ‹…› single angle quotes

License

This project is licensed under the MIT License.