/usr/gnu/man/cat.n/unset.n.Z(/usr/gnu/man/cat.n/unset.n.Z)

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NAME

       unset - Delete variables

SYNOPSIS

       unset ?-nocomplain? ?--? ?name name name ...?
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DESCRIPTION

       This  command  removes  one or more variables.  Each name is a variable
       name, specified in any of the ways acceptable to the set command.  If a
       name  refers  to  an  element  of an array then that element is removed
       without affecting the rest of the array.  If  a  name  consists  of  an
       array  name  with  no  parenthesized  index,  then  the entire array is
       deleted.  The unset command returns an  empty  string  as  result.   If |
       -nocomplain is specified as the first argument, any possible errors are |
       suppressed.  The option may not be  abbreviated,  in  order  to  disam- |
       biguate  it  from possible variable names.  The option -- indicates the |
       end of the options, and should be used if you wish to remove a variable |
       with  the  same  name  as  any of the options.  If an error occurs, any
       variables after the named one causing the error not deleted.  An  error
       can  occur when the named variable doesn't exist, or the name refers to
       an array element but the variable is a scalar, or the name refers to  a
       variable in a non-existent namespace.

EXAMPLE

       Create an array containing a mapping from some numbers to their squares
       and remove the array elements for non-prime numbers:
              array set squares {
                  1 1    6 36
                  2 4    7 49
                  3 9    8 64
                  4 16   9 81
                  5 25  10 100
              }

              puts "The squares are:"
              parray squares

              unset squares(1) squares(4) squares(6)
              unset squares(8) squares(9) squares(10)

              puts "The prime squares are:"
              parray squares

SEE ALSO

       set(n), trace(n), upvar(n)

KEYWORDS

       remove, variable

Tcl                                   8.4                             unset(n)