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lindex(3tcl)


NAME

   lindex - Retrieve an element from a list

SYNOPSIS

   lindex list ?index...?
______________________________________________________________________________

DESCRIPTION

   The  lindex command accepts a parameter, list, which it treats as a Tcl
   list. It also accepts zero or more indices into the list.  The  indices
   may  be  presented either consecutively on the command line, or grouped
   in a Tcl list and presented as a single argument.

   If no indices are presented, the command takes the form:
          lindex list
   or
          lindex list {}
   In this case, the return value of lindex is simply  the  value  of  the
   list parameter.

   When presented with a single index, the lindex command treats list as a
   Tcl list and returns the index'th element from  it  (0  refers  to  the
   first element of the list).  In extracting the element, lindex observes
   the same rules concerning braces and quotes and backslashes as the  Tcl
   command   interpreter;   however,  variable  substitution  and  command
   substitution do not occur.  If index is negative  or  greater  than  or
   equal  to  the  number  of  elements  in value, then an empty string is
   returned.  The interpretation of each simple index value is the same as 
   for  the  command  string index, supporting simple index arithmetic and 
   indices relative to the end of the list.

   If additional index arguments are supplied, then each argument is  used
   in  turn  to  select  an  element from the previous indexing operation,
   allowing the script to select elements from sublists.  The command,
          lindex $a 1 2 3
   or
          lindex $a {1 2 3}
   is synonymous with
          lindex [lindex [lindex $a 1] 2] 3

EXAMPLES

          lindex {a b c}
                 a b c
          lindex {a b c} {}
                 a b c
          lindex {a b c} 0
                 a
          lindex {a b c} 2
                 c
          lindex {a b c} end
                 c
          lindex {a b c} end-1
                 b
          lindex {{a b c} {d e f} {g h i}} 2 1
                 h
          lindex {{a b c} {d e f} {g h i}} {2 1}
                 h
          lindex {{{a b} {c d}} {{e f} {g h}}} 1 1 0
                 g
          lindex {{{a b} {c d}} {{e f} {g h}}} {1 1 0}
                 g

SEE ALSO

   list(3tcl), lappend(3tcl), linsert(3tcl), llength(3tcl), lsearch(3tcl),
   lset(3tcl), lsort(3tcl), lrange(3tcl), lreplace(3tcl), string(3tcl)

KEYWORDS

   element, index, list



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