[Klaus Saalfeld] A function `lselect` is proposed that selects a number of items from a list and returns them as a new list. In contrast to known `lindex` with multiple indices `lselect` doesn't operate on nested lists but on flat lists. The returned list contains the items in the same order as specified with the indices argument.

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# Returns from the specified list one or more elements identified by given indices.
# The first element in list is given by index 0, the last element of list is given by "end".
# An optional negative offset (e.g. "end-1") can be used to specify elements relative to the end of list.
# The list to operate on is passed by value.
proc lselect {value indices} {
   set result {}
   if {0 != [llength $value]} {
      foreach index $indices {
         if {0 == [string compare -length 3 $index end]} {
            set index [expr ([llength $value] - 1) [string range $index 3 end]]
         }
         if {($index >= 0) && ($index < [llength $value])} {
            lappend result [lindex $value $index]
         }
      }
   }
   return $result
}
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Some examples:
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% lselect {car house tiger penguin} {end-1 1 end 0}
tiger house penguin car

% lselect {banana pineapple orange} 1
pineapple

% lselect {tcl is great} {-1 17 end-8}
<empty>
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Many list operations are a special case of `lselect`. For example:
   * `lindex $x $n` corresponds to `lselect $x $n`. 
   * `lrange` means selecting a consecutive range of items from a list

`lselect` is moreover useful to implement stack or buffer like behavior with lists or to shuffle lists.

** See also **

   * [Additional list functions]