set(3tcl)

NAME

   set - Read and write variables

SYNOPSIS

   set varName ?value?
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DESCRIPTION

   Returns the value of variable varName.  If value is specified, then set
   the value of varName to value, creating a new variable if one does  not
   already  exist,  and  return  its  value.   If varName contains an open
   parenthesis and ends with a close parenthesis, then  it  refers  to  an
   array  element:   the  characters before the first open parenthesis are
   the name of the array, and the characters between the  parentheses  are
   the  index  within  the  array.   Otherwise  varName refers to a scalar
   variable.

   If varName includes namespace qualifiers  (in  the  array  name  if  it
   refers  to  an  array  element), or if varName is unqualified (does not
   include the names of any containing namespaces)  but  no  procedure  is
   active,  varName  refers  to a namespace variable resolved according to
   the rules described under NAME RESOLUTION in the namespace manual page.

   If a procedure is active  and  varName  is  unqualified,  then  varName
   refers  to  a  parameter  or  local  variable  of the procedure, unless
   varName was declared to resolve differently through one of the  global,
   variable or upvar commands.

EXAMPLES

   Store a random number in the variable r:
          set r [expr {rand()}]

   Store a short message in an array element:
          set anAry(msg) "Hello, World!"

   Store a short message in an array element specified by a variable:
          set elemName "msg"
          set anAry($elemName) "Hello, World!"

   Copy a value into the variable out from a variable whose name is stored
   in the vbl (note that it is often easier  to  use  arrays  in  practice
   instead of doing double-dereferencing):
          set in0 "small random"
          set in1 "large random"
          set vbl in[expr {rand() >= 0.5}]
          set out [set $vbl]

SEE ALSO

   expr(3tcl),  global(3tcl),  namespace(3tcl),  proc(3tcl),  trace(3tcl),
   unset(3tcl), upvar(3tcl), variable(3tcl)

KEYWORDS

   read, write, variable

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