bionic (3) unset.3tcl.gz

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 disambiguate 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 are  not  deleted.   An
       error  can  occur  when the named variable does not 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(3tcl), trace(3tcl), upvar(3tcl)

KEYWORDS

       remove, variable