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



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NAME
       lindex - Retrieve an element from a list

SYNOPSIS
       lindex list ?index...?
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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 inter-preter; interpreter;
       preter; 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.  If
       index has the value end, it refers to the last element in the list, and  end-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 com- |
       mand,                                                                                                 |
              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(n), lappend(n), linsert(n), llength(n), lsearch(n), lset(n), lsort(n), lrange(n), lreplace(n)    |


KEYWORDS
       element, index, list



Tcl                                                  8.4                                           lindex(n)