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



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NAME

       lreplace - Replace elements in a list with new elements


SYNOPSIS

       lreplace list first last ?element element ...?
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DESCRIPTION

       lreplace  returns  a new list formed by replacing zero or more elements
       of list with the element arguments.  first and last  are  index  values
       specifying  the  first  and last elements of the range to replace.  The
       index values first and last are interpreted the same  as  index  values
       for  the  command  string index, supporting simple index arithmetic and
       indices relative to the end of the list.  0 refers to the first element
       of the list, and end refers to the last element of the list.

       If either first or last is less than zero, it is considered to refer to
       before the first element of the list. This allows lreplace  to  prepend
       elements to list.  If either first or last indicates a position greater |
       than the index of the last element of the list, it is treated as if  it |
       is  an index one greater than the last element. This allows lreplace to |
       append elements to list.

       If last is less  than  first,  then  any  specified  elements  will  be
       inserted  into  the  list before the element specified by first with no
       elements being deleted.

       The element arguments specify zero or more new elements to be added  to
       the  list  in  place of those that were deleted.  Each element argument
       will become a separate element of the list.  If  no  element  arguments
       are  specified,  then  the  elements  between first and last are simply
       deleted.


EXAMPLES

       Replacing an element of a list with another:

              % lreplace {a b c d e} 1 1 foo
              a foo c d e

       Replacing two elements of a list with three:

              % lreplace {a b c d e} 1 2 three more elements
              a three more elements d e

       Deleting the last element from a list in a variable:

              % set var {a b c d e}
              a b c d e
              % set var [lreplace $var end end]
              a b c d

       A procedure to delete a given element from a list:

              proc lremove {listVariable value} {
                  upvar 1 $listVariable var
                  set idx [lsearch -exact $var $value]
                  set var [lreplace $var $idx $idx]
              }

       Appending elements to the list;  note  that  end+2  will  initially  be |
       treated  as  if  it is 6 here, but both that and 12345 are greater than |
       the index of the final item so they behave identically:                 |

              % set var {a b c d e}                                            |
              a b c d e                                                        |
              % set var [lreplace $var 12345 end+2 f g h i]                    |
              a b c d e f g h i                                                |


SEE ALSO

       list(n), lappend(n),  lindex(n),  linsert(n),  llength(n),  lsearch(n),
       lset(n), lrange(n), lsort(n), string(n)


KEYWORDS

       element, list, replace



Tcl                                   7.4                          lreplace(n)

tcl 8.6.9 - Generated Fri Nov 16 19:15:37 CST 2018
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