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Improve accuracy. In the .tex file, note the new "% BUG:" comments: an 

extra backslash is getting displayed in the generated HTML.
This commit is contained in:
Tim Peters 2001-02-20 11:24:35 +00:00
parent f0768c822b
commit 754ba589b7
2 changed files with 15 additions and 10 deletions
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19
Doc/lib/libdifflib.tex
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@ -53,8 +53,8 @@
\strong{Timing:} The basic Ratcliff-Obershelp algorithm is cubic \strong{Timing:} The basic Ratcliff-Obershelp algorithm is cubic
time in the worst case and quadratic time in the expected case. time in the worst case and quadratic time in the expected case.
\class{SequenceMatcher} is quadratic time for the worst case and has \class{SequenceMatcher} is quadratic time for the worst case and has
expected-case behavior dependent on how many elements the sequences expected-case behavior dependent in a complicated way on how many
have in common; best case time (no elements in common) is linear. elements the sequences have in common; best case time is linear.
\end{classdesc} \end{classdesc}
@ -68,6 +68,9 @@
\code{None} is equivalent to passing \code{lambda x: 0}, i.e.\ no \code{None} is equivalent to passing \code{lambda x: 0}, i.e.\ no
elements are ignored. For example, pass elements are ignored. For example, pass
% BUG: the HTML generated for this is
% BUG: lambda x: x in " \\t"
% BUG: i.e. it displays two backslashes.
\begin{verbatim} \begin{verbatim}
lambda x: x in " \\t" lambda x: x in " \\t"
\end{verbatim} \end{verbatim}
@ -138,7 +141,7 @@ of the other sequences.
junk happens to be adjacent to an interesting match. junk happens to be adjacent to an interesting match.
Here's the same example as before, but considering blanks to be junk. Here's the same example as before, but considering blanks to be junk.
That prevents \code{' abcd'} from matching the \code{ abcd} at the That prevents \code{' abcd'} from matching the \code{' abcd'} at the
tail end of the second sequence directly. Instead only the tail end of the second sequence directly. Instead only the
\code{'abcd'} can match, and matches the leftmost \code{'abcd'} in \code{'abcd'} can match, and matches the leftmost \code{'abcd'} in
the second sequence: the second sequence:
@ -217,8 +220,8 @@ replace a[3:4] (x) b[2:3] (y)
range [0, 1]. range [0, 1].
Where T is the total number of elements in both sequences, and M is Where T is the total number of elements in both sequences, and M is
the number of matches, this is 2,0*M / T. Note that this is \code{1} the number of matches, this is 2.0*M / T. Note that this is \code{1.}
if the sequences are identical, and \code{0} if they have nothing in if the sequences are identical, and \code{0.} if they have nothing in
common. common.
This is expensive to compute if \method{get_matching_blocks()} or This is expensive to compute if \method{get_matching_blocks()} or
@ -242,8 +245,10 @@ replace a[3:4] (x) b[2:3] (y)
\method{ratio()} or \method{quick_ratio()}. \method{ratio()} or \method{quick_ratio()}.
\end{methoddesc} \end{methoddesc}
The three methods that return the ratio of differences to similarities The three methods that return the ratio of matching to total characters
can give different results due to differing levels of approximation: can give different results due to differing levels of approximation,
although \method{quick_ratio()} and \method{real_quick_ratio()} are always
at least as large as \method{ratio()}:
\begin{verbatim} \begin{verbatim}
>>> s = SequenceMatcher(None, "abcd", "bcde") >>> s = SequenceMatcher(None, "abcd", "bcde")

6
Lib/difflib.py
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@ -92,9 +92,9 @@ See also function get_close_matches() in this module, which shows how
simple code building on SequenceMatcher can be used to do useful work. simple code building on SequenceMatcher can be used to do useful work.
Timing: Basic R-O is cubic time worst case and quadratic time expected Timing: Basic R-O is cubic time worst case and quadratic time expected
case. SequenceMatcher is quadratic time worst case and has expected-case case. SequenceMatcher is quadratic time for the worst case and has
behavior dependent on how many elements the sequences have in common; best expected-case behavior dependent in a complicated way on how many
case time (no elements in common) is linear. elements the sequences have in common; best case time is linear.
SequenceMatcher methods: SequenceMatcher methods: