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







append - Append to variable








append varName ?value value value ...?












Append all of the value arguments to the current value of
    variable varName. If varName does not exist, it is given a
    value equal to the concatenation of all the value arguments. The
    result of this command is the new value stored in variable varName.
    This command provides an efficient way to build up long variables
    incrementally. For example, “append a $b” is much more
    efficient than “set a $a$b” if $a is long.








Building a string of comma-separated numbers piecemeal using a
    loop.




set var 0
for {set i 1} {$i<=10} {incr i} {
   append var "," $i
}
puts $var
# Prints 0,1,2,3,4,5,6,7,8,9,10












concat(n), lappend(n)










append, variable







  

    
    Tcl