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Clarify descriptions of some operations; it's not always clear that

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strings are not actually modified.  Problem reported by Dr. Peter
Stoehr <peter.stoehr@weihenstephan.org>.
This commit is contained in:
Fred Drake 1998-12-21 18:56:13 +00:00
parent 3b02ddfa41
commit e848976fba
1 changed files with 107 additions and 103 deletions
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Doc/lib/libstring.tex
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@ -57,187 +57,191 @@ The functions defined in this module are:
\begin{funcdesc}{atof}{s} \begin{funcdesc}{atof}{s}
Convert a string to a floating point number. The string must have Convert a string to a floating point number. The string must have
the standard syntax for a floating point literal in Python, optionally the standard syntax for a floating point literal in Python,
preceded by a sign (\samp{+} or \samp{-}). Note that this behaves optionally preceded by a sign (\samp{+} or \samp{-}). Note that
identical to the built-in function this behaves identical to the built-in function
\function{float()}\bifuncindex{float} when passed a string. \function{float()}\bifuncindex{float} when passed a string.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{atoi}{s\optional{, base}} \begin{funcdesc}{atoi}{s\optional{, base}}
Convert string \var{s} to an integer in the given \var{base}. The Convert string \var{s} to an integer in the given \var{base}. The
string must consist of one or more digits, optionally preceded by a string must consist of one or more digits, optionally preceded by a
sign (\samp{+} or \samp{-}). The \var{base} defaults to 10. If it is sign (\samp{+} or \samp{-}). The \var{base} defaults to 10. If it
0, a default base is chosen depending on the leading characters of the is 0, a default base is chosen depending on the leading characters
string (after stripping the sign): \samp{0x} or \samp{0X} means 16, of the string (after stripping the sign): \samp{0x} or \samp{0X}
\samp{0} means 8, anything else means 10. If \var{base} is 16, a means 16, \samp{0} means 8, anything else means 10. If \var{base}
leading \samp{0x} or \samp{0X} is always accepted. Note that when is 16, a leading \samp{0x} or \samp{0X} is always accepted. Note
invoked without \var{base} or with \var{base} set to 10, this behaves that when invoked without \var{base} or with \var{base} set to 10,
identical to the built-in function \function{int()} when passed a string. this behaves identical to the built-in function \function{int()}
(Also note: for a more flexible interpretation of numeric literals, when passed a string. (Also note: for a more flexible
use the built-in function \function{eval()}\bifuncindex{eval}.) interpretation of numeric literals, use the built-in function
\function{eval()}\bifuncindex{eval}.)
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{atol}{s\optional{, base}} \begin{funcdesc}{atol}{s\optional{, base}}
Convert string \var{s} to a long integer in the given \var{base}. The Convert string \var{s} to a long integer in the given \var{base}.
string must consist of one or more digits, optionally preceded by a The string must consist of one or more digits, optionally preceded
sign (\samp{+} or \samp{-}). The \var{base} argument has the same by a sign (\samp{+} or \samp{-}). The \var{base} argument has the
meaning as for \function{atoi()}. A trailing \samp{l} or \samp{L} is same meaning as for \function{atoi()}. A trailing \samp{l} or
not allowed, except if the base is 0. Note that when invoked without \samp{L} is not allowed, except if the base is 0. Note that when
\var{base} or with \var{base} set to 10, this behaves identical to the invoked without \var{base} or with \var{base} set to 10, this
built-in function \function{long()}\bifuncindex{long} when passed a behaves identical to the built-in function
string. \function{long()}\bifuncindex{long} when passed a string.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{capitalize}{word} \begin{funcdesc}{capitalize}{word}
Capitalize the first character of the argument. Capitalize the first character of the argument.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{capwords}{s} \begin{funcdesc}{capwords}{s}
Split the argument into words using \function{split()}, capitalize Split the argument into words using \function{split()}, capitalize
each word using \function{capitalize()}, and join the capitalized each word using \function{capitalize()}, and join the capitalized
words using \function{join()}. Note that this replaces runs of words using \function{join()}. Note that this replaces runs of
whitespace characters by a single space, and removes leading and whitespace characters by a single space, and removes leading and
trailing whitespace. trailing whitespace.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{expandtabs}{s, tabsize} \begin{funcdesc}{expandtabs}{s, tabsize}
Expand tabs in a string, i.e.\ replace them by one or more spaces, Expand tabs in a string, i.e.\ replace them by one or more spaces,
depending on the current column and the given tab size. The column depending on the current column and the given tab size. The column
number is reset to zero after each newline occurring in the string. number is reset to zero after each newline occurring in the string.
This doesn't understand other non-printing characters or escape This doesn't understand other non-printing characters or escape
sequences. sequences.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{find}{s, sub\optional{, start\optional{,end}}} \begin{funcdesc}{find}{s, sub\optional{, start\optional{,end}}}
Return the lowest index in \var{s} where the substring \var{sub} is Return the lowest index in \var{s} where the substring \var{sub} is
found such that \var{sub} is wholly contained in found such that \var{sub} is wholly contained in
\code{\var{s}[\var{start}:\var{end}]}. Return \code{-1} on failure. \code{\var{s}[\var{start}:\var{end}]}. Return \code{-1} on failure.
Defaults for \var{start} and \var{end} and interpretation of negative Defaults for \var{start} and \var{end} and interpretation of
values is the same as for slices. negative values is the same as for slices.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{rfind}{s, sub\optional{, start\optional{, end}}} \begin{funcdesc}{rfind}{s, sub\optional{, start\optional{, end}}}
Like \function{find()} but find the highest index. Like \function{find()} but find the highest index.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{index}{s, sub\optional{, start\optional{, end}}} \begin{funcdesc}{index}{s, sub\optional{, start\optional{, end}}}
Like \function{find()} but raise \exception{ValueError} when the Like \function{find()} but raise \exception{ValueError} when the
substring is not found. substring is not found.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{rindex}{s, sub\optional{, start\optional{, end}}} \begin{funcdesc}{rindex}{s, sub\optional{, start\optional{, end}}}
Like \function{rfind()} but raise \exception{ValueError} when the Like \function{rfind()} but raise \exception{ValueError} when the
substring is not found. substring is not found.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{count}{s, sub\optional{, start\optional{, end}}} \begin{funcdesc}{count}{s, sub\optional{, start\optional{, end}}}
Return the number of (non-overlapping) occurrences of substring Return the number of (non-overlapping) occurrences of substring
\var{sub} in string \code{\var{s}[\var{start}:\var{end}]}. \var{sub} in string \code{\var{s}[\var{start}:\var{end}]}.
Defaults for \var{start} and \var{end} and interpretation of negative Defaults for \var{start} and \var{end} and interpretation of
values is the same as for slices. negative values is the same as for slices.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{lower}{s} \begin{funcdesc}{lower}{s}
Convert letters to lower case. Return a copy of \var{s}, but with upper case letters converted to
lower case.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{maketrans}{from, to} \begin{funcdesc}{maketrans}{from, to}
Return a translation table suitable for passing to Return a translation table suitable for passing to
\function{translate()} or \function{regex.compile()}, that will map \function{translate()} or \function{regex.compile()}, that will map
each character in \var{from} into the character at the same position each character in \var{from} into the character at the same position
in \var{to}; \var{from} and \var{to} must have the same length. in \var{to}; \var{from} and \var{to} must have the same length.
\strong{Warning:} don't use strings derived from \code{lowercase} and \strong{Warning:} don't use strings derived from \code{lowercase}
\code{uppercase} as arguments; in some locales, these don't have the and \code{uppercase} as arguments; in some locales, these don't have
same length. For case conversions, always use \function{lower()} and the same length. For case conversions, always use
\function{upper()}. \function{lower()} and \function{upper()}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{split}{s\optional{, sep\optional{, maxsplit}}} \begin{funcdesc}{split}{s\optional{, sep\optional{, maxsplit}}}
Return a list of the words of the string \var{s}. If the optional Return a list of the words of the string \var{s}. If the optional
second argument \var{sep} is absent or \code{None}, the words are second argument \var{sep} is absent or \code{None}, the words are
separated by arbitrary strings of whitespace characters (space, tab, separated by arbitrary strings of whitespace characters (space, tab,
newline, return, formfeed). If the second argument \var{sep} is newline, return, formfeed). If the second argument \var{sep} is
present and not \code{None}, it specifies a string to be used as the present and not \code{None}, it specifies a string to be used as the
word separator. The returned list will then have one more items than word separator. The returned list will then have one more items
the number of non-overlapping occurrences of the separator in the than the number of non-overlapping occurrences of the separator in
string. The optional third argument \var{maxsplit} defaults to 0. If the string. The optional third argument \var{maxsplit} defaults to
it is nonzero, at most \var{maxsplit} number of splits occur, and the 0. If it is nonzero, at most \var{maxsplit} number of splits occur,
remainder of the string is returned as the final element of the list and the remainder of the string is returned as the final element of
(thus, the list will have at most \code{\var{maxsplit}+1} elements). the list (thus, the list will have at most \code{\var{maxsplit}+1}
elements).
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{splitfields}{s\optional{, sep\optional{, maxsplit}}} \begin{funcdesc}{splitfields}{s\optional{, sep\optional{, maxsplit}}}
This function behaves identically to \function{split()}. (In the This function behaves identically to \function{split()}. (In the
past, \function{split()} was only used with one argument, while past, \function{split()} was only used with one argument, while
\function{splitfields()} was only used with two arguments.) \function{splitfields()} was only used with two arguments.)
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{join}{words\optional{, sep}} \begin{funcdesc}{join}{words\optional{, sep}}
Concatenate a list or tuple of words with intervening occurrences of Concatenate a list or tuple of words with intervening occurrences of
\var{sep}. The default value for \var{sep} is a single space \var{sep}. The default value for \var{sep} is a single space
character. It is always true that character. It is always true that
\samp{string.join(string.split(\var{s}, \var{sep}), \var{sep})} \samp{string.join(string.split(\var{s}, \var{sep}), \var{sep})}
equals \var{s}. equals \var{s}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{joinfields}{words\optional{, sep}} \begin{funcdesc}{joinfields}{words\optional{, sep}}
This function behaves identical to \function{join()}. (In the past, This function behaves identical to \function{join()}. (In the past,
\function{join()} was only used with one argument, while \function{join()} was only used with one argument, while
\function{joinfields()} was only used with two arguments.) \function{joinfields()} was only used with two arguments.)
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{lstrip}{s} \begin{funcdesc}{lstrip}{s}
Remove leading whitespace from the string \var{s}. Return a copy of \var{s} but without leading whitespace characters.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{rstrip}{s} \begin{funcdesc}{rstrip}{s}
Remove trailing whitespace from the string \var{s}. Return a copy of \var{s} but without trailing whitespace
characters.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{strip}{s} \begin{funcdesc}{strip}{s}
Remove leading and trailing whitespace from the string \var{s}. Return a copy of \var{s} without leading or trailing whitespace.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{swapcase}{s} \begin{funcdesc}{swapcase}{s}
Convert lower case letters to upper case and vice versa. Return a copy of \var{s}, but with lower case letters
converted to upper case and vice versa.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{translate}{s, table\optional{, deletechars}} \begin{funcdesc}{translate}{s, table\optional{, deletechars}}
Delete all characters from \var{s} that are in \var{deletechars} (if Delete all characters from \var{s} that are in \var{deletechars} (if
present), and then translate the characters using \var{table}, which present), and then translate the characters using \var{table}, which
must be a 256-character string giving the translation for each must be a 256-character string giving the translation for each
character value, indexed by its ordinal. character value, indexed by its ordinal.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{upper}{s} \begin{funcdesc}{upper}{s}
Convert letters to upper case. Return a copy of \var{s}, but with lower case letters converted to
upper case.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{ljust}{s, width} \begin{funcdesc}{ljust}{s, width}
\funcline{rjust}{s, width} \funcline{rjust}{s, width}
\funcline{center}{s, width} \funcline{center}{s, width}
These functions respectively left-justify, right-justify and center a These functions respectively left-justify, right-justify and center
string in a field of given width. a string in a field of given width. They return a string that is at
They return a string that is at least least \var{width} characters wide, created by padding the string
\var{width} \var{s} with spaces until the given width on the right, left or both
characters wide, created by padding the string sides. The string is never truncated.
\var{s}
with spaces until the given width on the right, left or both sides.
The string is never truncated.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{zfill}{s, width} \begin{funcdesc}{zfill}{s, width}
Pad a numeric string on the left with zero digits until the given Pad a numeric string on the left with zero digits until the given
width is reached. Strings starting with a sign are handled correctly. width is reached. Strings starting with a sign are handled
correctly.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{replace}{str, old, new\optional{, maxsplit}} \begin{funcdesc}{replace}{str, old, new\optional{, maxsplit}}
Return a copy of string \var{str} with all occurrences of substring Return a copy of string \var{str} with all occurrences of substring
\var{old} replaced by \var{new}. If the optional argument \var{old} replaced by \var{new}. If the optional argument
\var{maxsplit} is given, the first \var{maxsplit} occurrences are \var{maxsplit} is given, the first \var{maxsplit} occurrences are
replaced. replaced.
\end{funcdesc} \end{funcdesc}
This module is implemented in Python. Much of its functionality has This module is implemented in Python. Much of its functionality has