lindex(n) Tcl Built-In Commands lindex(n)

NAME
       lindex - Retrieve an element from a list

SYNOPSIS
       lliinnddeexx list ?index...?


DESCRIPTION
       The  lliinnddeexx 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 lliinnddeexx is simply  the  value  of  the |
       list parameter.                                                         |

       When presented with a single index, the lliinnddeexx 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, lliinnddeexx observes
       the same rules concerning braces and quotes and backslashes as the  Tcl
       command interpreter; however, variable substitution and command substi-
       tution 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.  If
       index has the value eenndd, it refers to the last element in the list, and
       eenndd-integer  refers to the last element in the list minus the specified
       integer offset.

       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                                |

EEXXAAMMPPLLEESS                                                                       |
              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(n),  lappend(n),  linsert(n),  llength(n),  lsearch(n),   lset(n), |
       lsort(n), lrange(n), lreplace(n)


KKEEYYWWOORRDDSS
       element, index, list



Tcl                                   8.4                            lindex(n)