Cannot evaluating variable within IF and For loop using TCL

Question

In following code in TCL I cannot seem evaluate the variable "a"

I'm evaluating x and y, in the same For Loop I have a IF statement that is checking for a range between x and y.

If valid then I'd like to perform some more calculations within the IF condition.

Every thing is fine up to the IF condition, but I cant seem to evaluate "a".

I'm trying to set "a" to the value of "y" for all the values within the range $min <= $x && $x <= $max

I would kindly request the experts to highlight the mistake.

for {set i 0} {$i < $lenght} {incr i} {

set x [expr ([lindex $cal1 $i])*$offset]

set y [expr ((cal2)/2) ]


if {$min <= $x && $x <= $max } {

puts "is Active"

set a [lindex $y $i]
puts a = $a

}

}

Peter Lewerin · Accepted Answer · 2015-06-20 14:31:19Z

1

There is a lot that seems problematic in your code.

In the first line, you use the variable lenght. Tcl doesn't care about spelling, but if you don't have such a variable (you might possibly have a length variable instead) you will get an error.
In the invocation expr ([lindex $cal1 $i])*$offset] you have an unnecessary parenthesis but no braces around the expression (the braces aren't mandatory but should be there unless there is a very good reason to omit them). Also: "offset" usually means something you add to, not multiply with, another value. The invocation expr {[lindex $cal1 $i] * $offset}] would be better.
The variable y is used as a list argument to lindex later on, but it's created as a scalar variable. Also, your expression divides a string (or rather, an invalid bareword) with 2. Maybe you meant lappend y [expr {$cal2 / 2}]? If you use lappend, each value will be added to the end of an existing list, or as the first element of a new list if y doesn't exist. This is usually what one wants, but it means that the list y should be reset using set y [list] or set y {} before entering the loop, to get rid of elements added earlier, if any.
puts a = $a won't work, because if there are more than one argument to puts they are expected to be the flag -nonewline and/or a channel id to send the output to. Maybe you meant puts "a = $a".

answered Jun 20, 2015 at 14:31

Peter Lewerin

13.3k1 gold badge29 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Anju Over a year ago

Hi Peter, Thank you for your feedback. Firstly apologies, I had to copy a snippet from a larger chuck of code. Therefore ended up making a few errors even when copying! I am using offset as you mentioned but also reusing it as a gain.

Collectives™ on Stack Overflow

Cannot evaluating variable within IF and For loop using TCL

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related