Tcl Source Code

% lindex $var 1
elements to
% \fBlrange\fR $var 1 1
{elements to}
.CE
.SH "SEE ALSO"
list(n), lappend(n), lindex(n), linsert(n), llength(n), lsearch(n),
lset(n), lremove(n), lreplace(n), lsort(n),
string(n)
.SH KEYWORDS
element, list, range, sublist
'\" Local Variables:
'\" mode: nroff
'\" fill-column: 78
'\" End:

'\"
'\" Copyright (c) 2019 Donal K. Fellows.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH lremove n 8.7 Tcl "Tcl Built-In Commands"
.so man.macros
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
lremove \- Remove elements from a list by index
.SH SYNOPSIS
\fBlremove \fIlist\fR ?\fIindex ...\fR?
.BE
.SH DESCRIPTION
.PP
\fBlremove\fR returns a new list formed by simultaneously removing zero or
more elements of \fIlist\fR at each of the indices given by an arbirary number
of \fIindex\fR arguments. The indices may be in any order and may be repeated;
the element at index will only be removed once.  The index values are
interpreted the same as index values for the command \fBstring index\fR,
supporting simple index arithmetic and indices relative to the end of the
list.  0 refers to the first element of the list, and \fBend\fR refers to the
last element of the list.
.SH EXAMPLES
.PP
Removing the third element of a list:
.PP
.CS
% \fBlremove\fR {a b c d e} 2
a b d e
.CE
.PP
Removing two elements from a list:
.PP
.CS
% \fBlremove\fR {a b c d e} end-1 1
a c e
.CE
.PP
Removing the same element indicated in two different ways:
.PP
.CS
% \fBlremove\fR {a b c d e} 2 end-2
a b d e
.CE
.SH "SEE ALSO"
list(n), lrange(n), lsearch(n), lsearch(n)
.SH KEYWORDS
element, list, remove
.\" Local variables:
.\" mode: nroff
.\" fill-column: 78
.\" End:

a b c d e
% set var [\fBlreplace\fR $var 12345 end+2 f g h i]
a b c d e f g h i
.CE
.VE TIP505
.SH "SEE ALSO"
list(n), lappend(n), lindex(n), linsert(n), llength(n), lsearch(n),
lset(n), lrange(n), lremove(n), lsort(n),
string(n)
.SH KEYWORDS
element, list, replace
.\" Local variables:
.\" mode: nroff
.\" fill-column: 78
.\" End:

    {"lindex",		Tcl_LindexObjCmd,	TclCompileLindexCmd,	NULL,	CMD_IS_SAFE},
    {"linsert",		Tcl_LinsertObjCmd,	TclCompileLinsertCmd,	NULL,	CMD_IS_SAFE},
    {"list",		Tcl_ListObjCmd,		TclCompileListCmd,	NULL,	CMD_IS_SAFE|CMD_COMPILES_EXPANDED},
    {"llength",		Tcl_LlengthObjCmd,	TclCompileLlengthCmd,	NULL,	CMD_IS_SAFE},
    {"lmap",		Tcl_LmapObjCmd,		TclCompileLmapCmd,	TclNRLmapCmd,	CMD_IS_SAFE},
    {"lpop",		Tcl_LpopObjCmd,		NULL,			NULL,	CMD_IS_SAFE},
    {"lrange",		Tcl_LrangeObjCmd,	TclCompileLrangeCmd,	NULL,	CMD_IS_SAFE},
    {"lremove", 	Tcl_LremoveObjCmd,	NULL,           	NULL,	CMD_IS_SAFE},
    {"lrepeat",		Tcl_LrepeatObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
    {"lreplace",	Tcl_LreplaceObjCmd,	TclCompileLreplaceCmd,	NULL,	CMD_IS_SAFE},
    {"lreverse",	Tcl_LreverseObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
    {"lsearch",		Tcl_LsearchObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
    {"lset",		Tcl_LsetObjCmd,		TclCompileLsetCmd,	NULL,	CMD_IS_SAFE},
    {"lsort",		Tcl_LsortObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
    {"package",		Tcl_PackageObjCmd,	NULL,			TclNRPackageObjCmd,	CMD_IS_SAFE},

    if (result != TCL_OK) {
	return result;
    }

    Tcl_SetObjResult(interp, TclListObjRange(objv[1], first, last));
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_LremoveObjCmd --
 *
 *	This procedure is invoked to process the "lremove" Tcl command. See the
 *	user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl object result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

typedef int list_index_t;

static int
LremoveIndexCompare(
    const void *el1Ptr,
    const void *el2Ptr)
{
    list_index_t idx1 = *((const list_index_t *) el1Ptr);
    list_index_t idx2 = *((const list_index_t *) el2Ptr);

    /*
     * This will put the larger element first.
     */

    return (idx1 < idx2) ? 1 : (idx1 > idx2) ? -1 : 0;
}

int
Tcl_LremoveObjCmd(
    ClientData notUsed,		/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *const objv[])	/* Argument objects. */
{
    int i, idxc;
    list_index_t listLen, *idxv, prevIdx, first, num;
    Tcl_Obj *listObj;

    /*
     * Parse the arguments.
     */

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "list ?index ...?");
	return TCL_ERROR;
    }

    listObj = objv[1];
    if (TclListObjLength(interp, listObj, &listLen) != TCL_OK) {
	return TCL_ERROR;
    }

    idxc = objc - 2;
    if (idxc == 0) {
	Tcl_SetObjResult(interp, listObj);
	return TCL_OK;
    }
    idxv = ckalloc((objc - 2) * sizeof(list_index_t));
    for (i = 2; i < objc; i++) {
	if (TclGetIntForIndexM(interp, objv[i], /*endValue*/ listLen - 1,
		&idxv[i - 2]) != TCL_OK) {
	    ckfree(idxv);
	    return TCL_ERROR;
	}
    }

    /*
     * Sort the indices, large to small so that when we remove an index we
     * don't change the indices still to be processed.
     */

    if (idxc > 1) {
	qsort(idxv, idxc, sizeof(list_index_t), LremoveIndexCompare);
    }

    /*
     * Make our working copy, then do the actual removes piecemeal.
     */

    if (Tcl_IsShared(listObj)) {
	listObj = TclListObjCopy(NULL, listObj);
    }
    num = 0;
    first = listLen;
    for (i = 0, prevIdx = -1 ; i < idxc ; i++) {
	list_index_t idx = idxv[i];

	/*
	 * Repeated index and sanity check.
	 */

	if (idx == prevIdx) {
	    continue;
	}
	prevIdx = idx;
	if (idx < 0 || idx >= listLen) {
	    continue;
	}

	/*
	 * Coalesce adjacent removes to reduce the number of copies.
	 */

	if (num == 0) {
	    num = 1;
	    first = idx;
	} else if (idx + 1 == first) {
	    num++;
	    first = idx;
	} else {
	    /*
	     * Note that this operation can't fail now; we know we have a list
	     * and we're only ever contracting that list.
	     */

	    (void) Tcl_ListObjReplace(interp, listObj, first, num, 0, NULL);
	    listLen -= num;
	    num = 1;
	    first = idx;
	}
    }
    if (num != 0) {
	(void) Tcl_ListObjReplace(interp, listObj, first, num, 0, NULL);
    }
    ckfree(idxv);
    Tcl_SetObjResult(interp, listObj);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_LrepeatObjCmd --
 *
 *	This procedure is invoked to process the "lrepeat" Tcl command. See

			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
MODULE_SCOPE int	Tcl_LpopObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
MODULE_SCOPE int	Tcl_LrangeObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
MODULE_SCOPE int	Tcl_LremoveObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
MODULE_SCOPE int	Tcl_LrepeatObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
MODULE_SCOPE int	Tcl_LreplaceObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);

::tcltest::loadTestedCommands
catch [list package require -exact Tcltest [info patchlevel]]

# Used for constraining memory leak tests
testConstraint memory [llength [info commands memory]]
testConstraint testobj [llength [info commands testobj]]

test cmdIL-1.1 {Tcl_LsortObjCmd procedure} -returnCodes error -body {
    lsort
} -result {wrong # args: should be "lsort ?-option value ...? list"}
test cmdIL-1.2 {Tcl_LsortObjCmd procedure} -returnCodes error -body {
    lsort -foo {1 3 2 5}
} -result {bad option "-foo": must be -ascii, -command, -decreasing, -dictionary, -increasing, -index, -indices, -integer, -nocase, -real, -stride, or -unique}
test cmdIL-1.3 {Tcl_LsortObjCmd procedure, default options} {

} -constraints testobj -body {
    lreverse [K $y [unset y]]
    lindex $x 0
} -cleanup {
    unset -nocomplain x y
    rename K {}
} -result 1

test cmdIL-8.1 {lremove command: error path} -returnCodes error -body {
    lremove
} -result {wrong # args: should be "lremove list ?index ...?"}
test cmdIL-8.2 {lremove command: error path} -returnCodes error -body {
    lremove {{}{}}
} -result {list element in braces followed by "{}" instead of space}
test cmdIL-8.3 {lremove command: error path} -returnCodes error -body {
    lremove {a b c} gorp
} -result {bad index "gorp": must be integer?[+-]integer? or end?[+-]integer?}
test cmdIL-8.4 {lremove command: no indices} -body {
    lremove {a b c}
} -result {a b c}
test cmdIL-8.5 {lremove command: before start} -body {
    lremove {a b c} -1
} -result {a b c}
test cmdIL-8.6 {lremove command: after end} -body {
    lremove {a b c} 3
} -result {a b c}
test cmdIL-8.7 {lremove command} -body {
    lremove {a b c} 0
} -result {b c}
test cmdIL-8.8 {lremove command} -body {
    lremove {a b c} 1
} -result {a c}
test cmdIL-8.9 {lremove command} -body {
    lremove {a b c} end
} -result {a b}
test cmdIL-8.10 {lremove command} -body {
    lremove {a b c} end-1
} -result {a c}
test cmdIL-8.11 {lremove command} -body {
    lremove {a b c d e} 1 3
} -result {a c e}
test cmdIL-8.12 {lremove command} -body {
    lremove {a b c d e} 3 1
} -result {a c e}
test cmdIL-8.13 {lremove command: same index twice} -body {
    lremove {a b c d e} 2 2
} -result {a b d e}
test cmdIL-8.14 {lremove command: same index twice} -body {
    lremove {a b c d e} 3 end-1
} -result {a b c e}
test cmdIL-8.15 {lremove command: many indices} -body {
    lremove {a b c d e} 1 3 1 4 0
} -result {c}

# This belongs in info test, but adding tests there breaks tests
# that compute source file line numbers.
test info-20.6 {Bug 3587651} -setup {
    namespace eval my {namespace eval tcl {namespace eval mathfunc {
        proc demo x {return 42}
    }}}} -body {    namespace eval my {expr {"demo" in [info functions]}}} -cleanup {
    namespace delete my
} -result 1


# cleanup
::tcltest::cleanupTests
return

# Local Variables:
# mode: tcl
# End: