Question

I need some help in defining arrays and displaying and looping thrrough them in TCL.

Here is how I would do them in php.

$date =array();
$size=0;
$date[$size] =$pre_event_date;
/* After doing some manpulation and calculations with $size */
for($i=0;$i<=$size;$i++){
    echo $date[$i];
}

I would like to do the same with tcl.Is the following code appropriate?

set size 0
set date[$size] $pre_event_date
#After performing some manipulation
for {set i 0} { $i <=$size } {incr i} {
    puts "$date[$i]";
}

Also can I define set $date as an array. Some like like:

set date array();

So i edited my code tried a simple test using RSeeger’s array implementation:

set date(0) 35
set date(1)  40
foreach key [array names date]{
   puts "${key}=$date($key)"
}

the above doesnt return anything there is probably some error.
I also tried:
puts $date($key) without quotes but that doesnt work either.

Answer 1

If you’re looking to index things by number (which your code implies), use a list. It is analogous to an array in C.

set mylist {}
lappend mylist a
lappend mylist b
lappend mylist c
lappend mylist d
foreach elem $mylist {
    puts $elem
}
// or if you really want to use for
for {set i 0} {$i < [length $mylist]} {incr i} {
    puts "${i}=[lindex $mylist $i]"
}

If you want to index things by string (or have a sparse list), you can use an array, which is a hashmap of key->value.

set myarr(chicken) animal
set myarr(cows) animal
set myarr(rock) mineral
set myarr(pea) vegetable

foreach key [array names myarr] {
    puts "${key}=$myarr($key)"
}