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







set - Read and write variables








set varName ?value?










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.








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]










expr(n), global(n), namespace(n), proc(n), trace(n), unset(n),
    upvar(n), variable(n)








read, write, variable







  

    
    Tcl