485 lines
18 KiB
Plaintext
485 lines
18 KiB
Plaintext
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.\"
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.\" Copyright (c) 1993 The Regents of the University of California.
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.\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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.\"
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.\" See the file "license.terms" for information on usage and redistribution
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.\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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.\"
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.TH string n 8.1 Tcl "Tcl Built-In Commands"
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.so man.macros
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.BS
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.\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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string \- Manipulate strings
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.SH SYNOPSIS
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\fBstring \fIoption arg \fR?\fIarg ...?\fR
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.BE
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.SH DESCRIPTION
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.PP
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Performs one of several string operations, depending on \fIoption\fR.
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The legal \fIoption\fRs (which may be abbreviated) are:
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.TP
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\fBstring cat\fR ?\fIstring1\fR? ?\fIstring2...\fR?
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.VS 8.6.2
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Concatenate the given \fIstring\fRs just like placing them directly
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next to each other and return the resulting compound string. If no
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\fIstring\fRs are present, the result is an empty string.
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.RS
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.PP
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This primitive is occasionally handier than juxtaposition of strings
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when mixed quoting is wanted, or when the aim is to return the result
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of a concatenation without resorting to \fBreturn\fR \fB\-level 0\fR,
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and is more efficient than building a list of arguments and using
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\fBjoin\fR with an empty join string.
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.RE
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.VE
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.TP
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\fBstring compare\fR ?\fB\-nocase\fR? ?\fB\-length\fI length\fR? \fIstring1 string2\fR
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.
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Perform a character-by-character comparison of strings \fIstring1\fR
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and \fIstring2\fR. Returns \-1, 0, or 1, depending on whether
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\fIstring1\fR is lexicographically less than, equal to, or greater
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than \fIstring2\fR. If \fB\-length\fR is specified, then only the
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first \fIlength\fR characters are used in the comparison. If
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\fB\-length\fR is negative, it is ignored. If \fB\-nocase\fR is
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specified, then the strings are compared in a case-insensitive manner.
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.TP
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\fBstring equal\fR ?\fB\-nocase\fR? ?\fB\-length\fI length\fR? \fIstring1 string2\fR
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.
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Perform a character-by-character comparison of strings \fIstring1\fR
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and \fIstring2\fR. Returns 1 if \fIstring1\fR and \fIstring2\fR are
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identical, or 0 when not. If \fB\-length\fR is specified, then only
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the first \fIlength\fR characters are used in the comparison. If
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\fB\-length\fR is negative, it is ignored. If \fB\-nocase\fR is
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specified, then the strings are compared in a case-insensitive manner.
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.TP
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\fBstring first \fIneedleString haystackString\fR ?\fIstartIndex\fR?
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.
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Search \fIhaystackString\fR for a sequence of characters that exactly match
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the characters in \fIneedleString\fR. If found, return the index of the
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first character in the first such match within \fIhaystackString\fR. If not
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found, return \-1. If \fIstartIndex\fR is specified (in any of the
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forms described in \fBSTRING INDICES\fR), then the search is
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constrained to start with the character in \fIhaystackString\fR specified by
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the index. For example,
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.RS
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.PP
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.CS
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\fBstring first a 0a23456789abcdef 5\fR
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.CE
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.PP
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will return \fB10\fR, but
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.PP
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.CS
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\fBstring first a 0123456789abcdef 11\fR
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.CE
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.PP
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will return \fB\-1\fR.
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.RE
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.TP
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\fBstring index \fIstring charIndex\fR
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.
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Returns the \fIcharIndex\fR'th character of the \fIstring\fR argument.
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A \fIcharIndex\fR of 0 corresponds to the first character of the
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string. \fIcharIndex\fR may be specified as described in the
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\fBSTRING INDICES\fR section.
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.RS
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.PP
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If \fIcharIndex\fR is less than 0 or greater than or equal to the
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length of the string then this command returns an empty string.
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.RE
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.TP
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\fBstring is \fIclass\fR ?\fB\-strict\fR? ?\fB\-failindex \fIvarname\fR? \fIstring\fR
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.
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Returns 1 if \fIstring\fR is a valid member of the specified character
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class, otherwise returns 0. If \fB\-strict\fR is specified, then an
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empty string returns 0, otherwise an empty string will return 1 on
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any class. If \fB\-failindex\fR is specified, then if the function
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returns 0, the index in the string where the class was no longer valid
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will be stored in the variable named \fIvarname\fR. The \fIvarname\fR
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will not be set if \fBstring is\fR returns 1. The following character
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classes are recognized (the class name can be abbreviated):
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.RS
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.IP \fBalnum\fR 12
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Any Unicode alphabet or digit character.
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.IP \fBalpha\fR 12
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Any Unicode alphabet character.
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.IP \fBascii\fR 12
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Any character with a value less than \eu0080 (those that are in the
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7\-bit ascii range).
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.IP \fBboolean\fR 12
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Any of the forms allowed to \fBTcl_GetBoolean\fR.
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.IP \fBcontrol\fR 12
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Any Unicode control character.
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.IP \fBdigit\fR 12
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Any Unicode digit character. Note that this includes characters
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outside of the [0\-9] range.
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.IP \fBdouble\fR 12
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Any of the forms allowed to \fBTcl_GetDoubleFromObj\fR.
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.IP \fBentier\fR 12
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.VS 8.6
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Any of the valid string formats for an integer value of arbitrary size
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in Tcl, with optional surrounding whitespace. The formats accepted are
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exactly those accepted by the C routine \fBTcl_GetBignumFromObj\fR.
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.VE
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.IP \fBfalse\fR 12
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Any of the forms allowed to \fBTcl_GetBoolean\fR where the value is
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false.
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.IP \fBgraph\fR 12
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Any Unicode printing character, except space.
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.IP \fBinteger\fR 12
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Any of the valid string formats for a 32-bit integer value in Tcl,
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with optional surrounding whitespace. In case of overflow in
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the value, 0 is returned and the \fIvarname\fR will contain \-1.
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.IP \fBlist\fR 12
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Any proper list structure, with optional surrounding whitespace. In
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case of improper list structure, 0 is returned and the \fIvarname\fR
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will contain the index of the
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.QW element
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where the list parsing fails, or \-1 if this cannot be determined.
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.IP \fBlower\fR 12
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Any Unicode lower case alphabet character.
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.IP \fBprint\fR 12
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Any Unicode printing character, including space.
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.IP \fBpunct\fR 12
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Any Unicode punctuation character.
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.IP \fBspace\fR 12
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Any Unicode whitespace character, mongolian vowel separator
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(U+180e), zero width space (U+200b), word joiner (U+2060) or
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zero width no-break space (U+feff) (=BOM).
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.IP \fBtrue\fR 12
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Any of the forms allowed to \fBTcl_GetBoolean\fR where the value is
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true.
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.IP \fBupper\fR 12
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Any upper case alphabet character in the Unicode character set.
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.IP \fBwideinteger\fR 12
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Any of the valid forms for a wide integer in Tcl, with optional
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surrounding whitespace. In case of overflow in the value, 0 is
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returned and the \fIvarname\fR will contain \-1.
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.IP \fBwordchar\fR 12
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Any Unicode word character. That is any alphanumeric character, and
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any Unicode connector punctuation characters (e.g. underscore).
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.IP \fBxdigit\fR 12
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Any hexadecimal digit character ([0\-9A\-Fa\-f]).
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.PP
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In the case of \fBboolean\fR, \fBtrue\fR and \fBfalse\fR, if the
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function will return 0, then the \fIvarname\fR will always be set to
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0, due to the varied nature of a valid boolean value.
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.RE
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.TP
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\fBstring last \fIneedleString haystackString\fR ?\fIlastIndex\fR?
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.
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Search \fIhaystackString\fR for a sequence of characters that exactly match
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the characters in \fIneedleString\fR. If found, return the index of the
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first character in the last such match within \fIhaystackString\fR. If there
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is no match, then return \-1. If \fIlastIndex\fR is specified (in any
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of the forms described in \fBSTRING INDICES\fR), then only the
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characters in \fIhaystackString\fR at or before the specified \fIlastIndex\fR
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will be considered by the search. For example,
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.RS
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.PP
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.CS
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\fBstring last a 0a23456789abcdef 15\fR
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.CE
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.PP
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will return \fB10\fR, but
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.PP
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.CS
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\fBstring last a 0a23456789abcdef 9\fR
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.CE
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.PP
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will return \fB1\fR.
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.RE
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.TP
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\fBstring length \fIstring\fR
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.
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Returns a decimal string giving the number of characters in
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\fIstring\fR. Note that this is not necessarily the same as the
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number of bytes used to store the string. If the value is a
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byte array value (such as those returned from reading a binary encoded
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channel), then this will return the actual byte length of the value.
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.TP
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\fBstring map\fR ?\fB\-nocase\fR? \fImapping string\fR
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.
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Replaces substrings in \fIstring\fR based on the key-value pairs in
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\fImapping\fR. \fImapping\fR is a list of \fIkey value key value ...\fR
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as in the form returned by \fBarray get\fR. Each instance of a
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key in the string will be replaced with its corresponding value. If
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\fB\-nocase\fR is specified, then matching is done without regard to
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case differences. Both \fIkey\fR and \fIvalue\fR may be multiple
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characters. Replacement is done in an ordered manner, so the key
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appearing first in the list will be checked first, and so on.
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\fIstring\fR is only iterated over once, so earlier key replacements
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will have no affect for later key matches. For example,
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.RS
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.PP
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.CS
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\fBstring map {abc 1 ab 2 a 3 1 0} 1abcaababcabababc\fR
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.CE
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.PP
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will return the string \fB01321221\fR.
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.PP
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Note that if an earlier \fIkey\fR is a prefix of a later one, it will
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completely mask the later one. So if the previous example is
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reordered like this,
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.PP
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.CS
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\fBstring map {1 0 ab 2 a 3 abc 1} 1abcaababcabababc\fR
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.CE
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.PP
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it will return the string \fB02c322c222c\fR.
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.RE
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.TP
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\fBstring match\fR ?\fB\-nocase\fR? \fIpattern\fR \fIstring\fR
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.
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See if \fIpattern\fR matches \fIstring\fR; return 1 if it does, 0 if
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it does not. If \fB\-nocase\fR is specified, then the pattern attempts
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to match against the string in a case insensitive manner. For the two
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strings to match, their contents must be identical except that the
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following special sequences may appear in \fIpattern\fR:
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.RS
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.IP \fB*\fR 10
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Matches any sequence of characters in \fIstring\fR, including a null
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string.
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.IP \fB?\fR 10
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Matches any single character in \fIstring\fR.
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.IP \fB[\fIchars\fB]\fR 10
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Matches any character in the set given by \fIchars\fR. If a sequence
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of the form \fIx\fB\-\fIy\fR appears in \fIchars\fR, then any
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character between \fIx\fR and \fIy\fR, inclusive, will match. When
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used with \fB\-nocase\fR, the end points of the range are converted to
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lower case first. Whereas {[A\-z]} matches
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.QW _
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when matching case-sensitively (since
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.QW _
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falls between the
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.QW Z
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and
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.QW a ),
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with \fB\-nocase\fR this is considered like {[A\-Za\-z]} (and
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probably what was meant in the first place).
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.IP \fB\e\fIx\fR 10
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Matches the single character \fIx\fR. This provides a way of avoiding
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the special interpretation of the characters \fB*?[]\e\fR in
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\fIpattern\fR.
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.RE
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.TP
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\fBstring range \fIstring first last\fR
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.
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Returns a range of consecutive characters from \fIstring\fR, starting
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with the character whose index is \fIfirst\fR and ending with the
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character whose index is \fIlast\fR. An index of 0 refers to the first
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character of the string. \fIfirst\fR and \fIlast\fR may be specified
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as for the \fBindex\fR method. If \fIfirst\fR is less than zero then
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it is treated as if it were zero, and if \fIlast\fR is greater than or
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equal to the length of the string then it is treated as if it were
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\fBend\fR. If \fIfirst\fR is greater than \fIlast\fR then an empty
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string is returned.
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.TP
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\fBstring repeat \fIstring count\fR
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.
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Returns \fIstring\fR repeated \fIcount\fR number of times.
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.TP
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\fBstring replace \fIstring first last\fR ?\fInewstring\fR?
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.
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Removes a range of consecutive characters from \fIstring\fR, starting
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with the character whose index is \fIfirst\fR and ending with the
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character whose index is \fIlast\fR. An index of 0 refers to the
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first character of the string. \fIFirst\fR and \fIlast\fR may be
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specified as for the \fBindex\fR method. If \fInewstring\fR is
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specified, then it is placed in the removed character range. If
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\fIfirst\fR is less than zero then it is treated as if it were zero,
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and if \fIlast\fR is greater than or equal to the length of the string
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then it is treated as if it were \fBend\fR. The initial string is
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returned untouched, if \fIfirst\fR is greater than \fIlast\fR, or if
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\fIfirst\fR is equal to or greater than the length of the initial string,
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or \fIlast\fR is less than 0.
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.TP
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\fBstring reverse \fIstring\fR
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.
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Returns a string that is the same length as \fIstring\fR but with its
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characters in the reverse order.
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.TP
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\fBstring tolower \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR?
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.
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Returns a value equal to \fIstring\fR except that all upper (or title)
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case letters have been converted to lower case. If \fIfirst\fR is
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specified, it refers to the first char index in the string to start
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modifying. If \fIlast\fR is specified, it refers to the char index in
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the string to stop at (inclusive). \fIfirst\fR and \fIlast\fR may be
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specified using the forms described in \fBSTRING INDICES\fR.
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.TP
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\fBstring totitle \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR?
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.
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Returns a value equal to \fIstring\fR except that the first character
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in \fIstring\fR is converted to its Unicode title case variant (or
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upper case if there is no title case variant) and the rest of the
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string is converted to lower case. If \fIfirst\fR is specified, it
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refers to the first char index in the string to start modifying. If
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\fIlast\fR is specified, it refers to the char index in the string to
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stop at (inclusive). \fIfirst\fR and \fIlast\fR may be specified
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using the forms described in \fBSTRING INDICES\fR.
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.TP
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\fBstring toupper \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR?
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.
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Returns a value equal to \fIstring\fR except that all lower (or title)
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|
case letters have been converted to upper case. If \fIfirst\fR is
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|
specified, it refers to the first char index in the string to start
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modifying. If \fIlast\fR is specified, it refers to the char index in
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the string to stop at (inclusive). \fIfirst\fR and \fIlast\fR may be
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specified using the forms described in \fBSTRING INDICES\fR.
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.TP
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|
\fBstring trim \fIstring\fR ?\fIchars\fR?
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.
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Returns a value equal to \fIstring\fR except that any leading or
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trailing characters present in the string given by \fIchars\fR are removed. If
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\fIchars\fR is not specified then white space is removed (any character
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for which \fBstring is space\fR returns 1, and "\e0").
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.TP
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\fBstring trimleft \fIstring\fR ?\fIchars\fR?
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.
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Returns a value equal to \fIstring\fR except that any leading
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characters present in the string given by \fIchars\fR are removed. If
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\fIchars\fR is not specified then white space is removed (any character
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for which \fBstring is space\fR returns 1, and "\e0").
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.TP
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\fBstring trimright \fIstring\fR ?\fIchars\fR?
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.
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Returns a value equal to \fIstring\fR except that any trailing
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characters present in the string given by \fIchars\fR are removed. If
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\fIchars\fR is not specified then white space is removed (any character
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for which \fBstring is space\fR returns 1, and "\e0").
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.SS "OBSOLETE SUBCOMMANDS"
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.PP
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These subcommands are currently supported, but are likely to go away in a
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future release as their functionality is either virtually never used or highly
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misleading.
|
||
|
.TP
|
||
|
\fBstring bytelength \fIstring\fR
|
||
|
.
|
||
|
Returns a decimal string giving the number of bytes used to represent
|
||
|
\fIstring\fR in memory when encoded as Tcl's internal modified UTF\-8;
|
||
|
Tcl may use other encodings for \fIstring\fR as well, and does not
|
||
|
guarantee to only use a single encoding for a particular \fIstring\fR.
|
||
|
Because UTF\-8 uses a variable number of bytes to represent Unicode
|
||
|
characters, the byte length will not be the same as the character
|
||
|
length in general. The cases where a script cares about the byte
|
||
|
length are rare.
|
||
|
.RS
|
||
|
.PP
|
||
|
In almost all cases, you should use the
|
||
|
\fBstring length\fR operation (including determining the length of a
|
||
|
Tcl byte array value). Refer to the \fBTcl_NumUtfChars\fR manual
|
||
|
entry for more details on the UTF\-8 representation.
|
||
|
.PP
|
||
|
Formally, the \fBstring bytelength\fR operation returns the content of
|
||
|
the \fIlength\fR field of the \fBTcl_Obj\fR structure, after calling
|
||
|
\fBTcl_GetString\fR to ensure that the \fIbytes\fR field is populated.
|
||
|
This is highly unlikely to be useful to Tcl scripts, as Tcl's internal
|
||
|
encoding is not strict UTF\-8, but rather a modified CESU\-8 with a
|
||
|
denormalized NUL (identical to that used in a number of places by
|
||
|
Java's serialization mechanism) to enable basic processing with
|
||
|
non-Unicode-aware C functions. As this representation should only
|
||
|
ever be used by Tcl's implementation, the number of bytes used to
|
||
|
store the representation is of very low value (except to C extension
|
||
|
code, which has direct access for the purpose of memory management,
|
||
|
etc.)
|
||
|
.PP
|
||
|
\fICompatibility note:\fR it is likely that this subcommand will be
|
||
|
withdrawn in a future version of Tcl. It is better to use the
|
||
|
\fBencoding convertto\fR command to convert a string to a known
|
||
|
encoding and then apply \fBstring length\fR to that.
|
||
|
.PP
|
||
|
.CS
|
||
|
\fBstring length\fR [encoding convertto utf-8 $theString]
|
||
|
.CE
|
||
|
.RE
|
||
|
.TP
|
||
|
\fBstring wordend \fIstring charIndex\fR
|
||
|
.
|
||
|
Returns the index of the character just after the last one in the word
|
||
|
containing character \fIcharIndex\fR of \fIstring\fR. \fIcharIndex\fR
|
||
|
may be specified using the forms in \fBSTRING INDICES\fR. A word is
|
||
|
considered to be any contiguous range of alphanumeric (Unicode letters
|
||
|
or decimal digits) or underscore (Unicode connector punctuation)
|
||
|
characters, or any single character other than these.
|
||
|
.TP
|
||
|
\fBstring wordstart \fIstring charIndex\fR
|
||
|
.
|
||
|
Returns the index of the first character in the word containing character
|
||
|
\fIcharIndex\fR of \fIstring\fR. \fIcharIndex\fR may be specified using the
|
||
|
forms in \fBSTRING INDICES\fR. A word is considered to be any contiguous
|
||
|
range of alphanumeric (Unicode letters or decimal digits) or underscore
|
||
|
(Unicode connector punctuation) characters, or any single character other than
|
||
|
these.
|
||
|
.SH "STRING INDICES"
|
||
|
.PP
|
||
|
When referring to indices into a string (e.g., for \fBstring index\fR
|
||
|
or \fBstring range\fR) the following formats are supported:
|
||
|
.IP \fIinteger\fR 10
|
||
|
For any index value that passes \fBstring is integer \-strict\fR,
|
||
|
the char specified at this integral index (e.g., \fB2\fR would refer to the
|
||
|
.QW c
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.IP \fBend\fR 10
|
||
|
The last char of the string (e.g., \fBend\fR would refer to the
|
||
|
.QW d
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.IP \fBend\-\fIN\fR 10
|
||
|
The last char of the string minus the specified integer offset \fIN\fR (e.g.,
|
||
|
.QW \fBend\-1\fR
|
||
|
would refer to the
|
||
|
.QW c
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.IP \fBend+\fIN\fR 10
|
||
|
The last char of the string plus the specified integer offset \fIN\fR (e.g.,
|
||
|
.QW \fBend+\-1\fR
|
||
|
would refer to the
|
||
|
.QW c
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.IP \fIM\fB+\fIN\fR 10
|
||
|
The char specified at the integral index that is the sum of
|
||
|
integer values \fIM\fR and \fIN\fR (e.g.,
|
||
|
.QW \fB1+1\fR
|
||
|
would refer to the
|
||
|
.QW c
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.IP \fIM\fB\-\fIN\fR 10
|
||
|
The char specified at the integral index that is the difference of
|
||
|
integer values \fIM\fR and \fIN\fR (e.g.,
|
||
|
.QW \fB2\-1\fR
|
||
|
would refer to the
|
||
|
.QW b
|
||
|
in
|
||
|
.QW abcd ).
|
||
|
.PP
|
||
|
In the specifications above, the integer value \fIM\fR contains no
|
||
|
trailing whitespace and the integer value \fIN\fR contains no
|
||
|
leading whitespace.
|
||
|
.SH EXAMPLE
|
||
|
.PP
|
||
|
Test if the string in the variable \fIstring\fR is a proper non-empty
|
||
|
prefix of the string \fBfoobar\fR.
|
||
|
.PP
|
||
|
.CS
|
||
|
set length [\fBstring length\fR $string]
|
||
|
if {$length == 0} {
|
||
|
set isPrefix 0
|
||
|
} else {
|
||
|
set isPrefix [\fBstring equal\fR \-length $length $string "foobar"]
|
||
|
}
|
||
|
.CE
|
||
|
.SH "SEE ALSO"
|
||
|
expr(n), list(n)
|
||
|
.SH KEYWORDS
|
||
|
case conversion, compare, index, match, pattern, string, word, equal,
|
||
|
ctype, character, reverse
|
||
|
.\" Local Variables:
|
||
|
.\" mode: nroff
|
||
|
.\" End:
|