I' trying to get a value of variable, which name consists of string "a" and iterator "i" (in this short example I skipped for loop). I was trying to do it with concat and append, with [] and "" and nothing working. Is there any solution for this problem?
set b0 0
set i 0
set a$i $b$i (here is my problem)
puts $a$i
puts should show "0"
To read from a variable whose name is computed, use set with only one argument:
set a$i [set b$i]
puts [set a$i]
(There's a real sense in which the $ is a syntactic shorthand for calling this form of set; indeed, the $ syntax is newer.)
In this case, you are almost certainly better off rewriting your code to use associative arrays.
set b(0) 0
set i 0
set a($i) $b($i)
puts $a($i)