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Binary search in a sorted text file

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Description

This Python 3 module provides functionality to search inside sorted text files. The lines of the files need not be all of the same length. The module contains the following functions:

  • text_bisect_left(a, x, lo=0, hi=None, key=lambda x: x) locates the insertion point for line x in seekable filelike object a consisting of a number of lines; x must be specified without a trailing newline. a must use \n as the newline character and must not perform any line endings translation (use open(..., newline='\n')). The parameters lo and hi, if specified, must be absolute positions within object a, and specify which part of a to search; the default is to search the entire a. The character pointed to by hi (or the last character of the object, if hi is unspecified) must be a newline. key is a function that is used to compare each line of a with x; line endings are removed from the lines of a before comparison. a must be sorted or the result will be undefined. If x compares equal to a line in a, the returned insertion point is the beginning of that line. The initial position of a is discarded. The function returns the insertion point, which is an integer between lo and hi+1, pointing to the beginning of a line; when it exits, a is positioned there.

  • text_bisect_right() is the same as text_bisect_left(), except that if x compares equal to a line in a, the returned insertion point is the beginning of the next line.

  • text_bisect() is the same as text_bisect_right().

License

Copyright (C) 2016 Antonis Christofides

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

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