- NAME
- lsort - Sort the elements of a list
- SYNOPSIS
- lsort ?options? list
- DESCRIPTION
- -ascii
- -dictionary
- -integer
- -real
- -command command
- -increasing
- -decreasing
- -index index
- KEYWORDS
lsort - Sort the elements of a list
lsort ?options? list
This command sorts the elements of list, returning a new
list in sorted order. The implementation of the lsort command
uses the merge-sort algorithm which is a stable sort that has O(n log
n) performance characteristics.
By default ASCII sorting is used with the result returned in
increasing order. However, any of the following options may be
specified before list to control the sorting process (unique
abbreviations are accepted):
- -ascii
-
Use string comparison with ASCII collation order. This is
the default.
- -dictionary
-
Use dictionary-style comparison. This is the same as -ascii
except (a) case is ignored except as a tie-breaker and (b) if two
strings contain embedded numbers, the numbers compare as integers,
not characters. For example, in -dictionary mode, bigBoy
sorts between bigbang and bigboy, and x10y
sorts between x9y and x11y.
- -integer
-
Convert list elements to integers and use integer comparison.
- -real
-
Convert list elements to floating-point values and use floating
comparison.
- -command command
-
Use command as a comparison command.
To compare two elements, evaluate a Tcl script consisting of
command with the two elements appended as additional
arguments. The script should return an integer less than,
equal to, or greater than zero if the first element is to
be considered less than, equal to, or greater than the second,
respectively.
- -increasing
-
Sort the list in increasing order (``smallest'' items first).
This is the default.
- -decreasing
-
Sort the list in decreasing order (``largest'' items first).
- -index index
-
If this option is specified, each of the elements of list must
itself be a proper Tcl sublist. Instead of sorting based on whole sublists,
lsort will extract the index'th element from each sublist
and sort based on the given element. The keyword end is allowed
for the index to sort on the last sublist element. For example,
lsort -integer -index 1 {{First 24} {Second 18} {Third 30}}
returns {Second 18} {First 24} {Third 30}.
This option is much more efficient than using -command
to achieve the same effect.
element, list, order, sort
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.
Copyright © 1999 Scriptics Corporation
Copyright © 1995-1997 Roger E. Critchlow Jr.