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74 lines
3.2 KiB
TeX
74 lines
3.2 KiB
TeX
\section{\module{regsub} ---
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String operations using regular expressions}
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\declaremodule{standard}{regsub}
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\modulesynopsis{Substitution and splitting operations that use
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regular expressions.}
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This module defines a number of functions useful for working with
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regular expressions (see built-in module \refmodule{regex}).
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Warning: these functions are not thread-safe.
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\strong{Obsolescence note:}
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This module is obsolete as of Python version 1.5; it is still being
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maintained because much existing code still uses it. All new code in
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need of regular expressions should use the new \refmodule{re} module, which
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supports the more powerful and regular Perl-style regular expressions.
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Existing code should be converted. The standard library module
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\module{reconvert} helps in converting \refmodule{regex} style regular
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expressions to \refmodule{re} style regular expressions. (For more
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conversion help, see Andrew Kuchling's\index{Kuchling, Andrew}
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``regex-to-re HOWTO'' at
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\url{http://www.python.org/doc/howto/regex-to-re/}.)
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\begin{funcdesc}{sub}{pat, repl, str}
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Replace the first occurrence of pattern \var{pat} in string
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\var{str} by replacement \var{repl}. If the pattern isn't found,
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the string is returned unchanged. The pattern may be a string or an
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already compiled pattern. The replacement may contain references
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\samp{\e \var{digit}} to subpatterns and escaped backslashes.
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\end{funcdesc}
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\begin{funcdesc}{gsub}{pat, repl, str}
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Replace all (non-overlapping) occurrences of pattern \var{pat} in
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string \var{str} by replacement \var{repl}. The same rules as for
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\code{sub()} apply. Empty matches for the pattern are replaced only
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when not adjacent to a previous match, so e.g.
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\code{gsub('', '-', 'abc')} returns \code{'-a-b-c-'}.
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\end{funcdesc}
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\begin{funcdesc}{split}{str, pat\optional{, maxsplit}}
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Split the string \var{str} in fields separated by delimiters matching
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the pattern \var{pat}, and return a list containing the fields. Only
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non-empty matches for the pattern are considered, so e.g.
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\code{split('a:b', ':*')} returns \code{['a', 'b']} and
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\code{split('abc', '')} returns \code{['abc']}. The \var{maxsplit}
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defaults to 0. If it is nonzero, only \var{maxsplit} number of splits
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occur, and the remainder of the string is returned as the final
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element of the list.
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\end{funcdesc}
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\begin{funcdesc}{splitx}{str, pat\optional{, maxsplit}}
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Split the string \var{str} in fields separated by delimiters matching
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the pattern \var{pat}, and return a list containing the fields as well
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as the separators. For example, \code{splitx('a:::b', ':*')} returns
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\code{['a', ':::', 'b']}. Otherwise, this function behaves the same
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as \code{split}.
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\end{funcdesc}
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\begin{funcdesc}{capwords}{s\optional{, pat}}
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Capitalize words separated by optional pattern \var{pat}. The default
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pattern uses any characters except letters, digits and underscores as
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word delimiters. Capitalization is done by changing the first
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character of each word to upper case.
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\end{funcdesc}
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\begin{funcdesc}{clear_cache}{}
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The regsub module maintains a cache of compiled regular expressions,
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keyed on the regular expression string and the syntax of the regex
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module at the time the expression was compiled. This function clears
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that cache.
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\end{funcdesc}
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