bionic (3) lindex.3tcl.gz

Provided by: tcl8.5-doc_8.5.19-4_all bug

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