CODEWITHSUNDEEP
arrayslisttcl
PYPL
PYPL

Reputation: 1849

List of Array tcl

I have 5 arrays and i want to iterate over them one by one, so I'm thinking to add these arrays to another array and access them one by one with indexes

array set ListOfArrays {1 $array1 2 $array2 3 $array3 4 $array4 5 $array5}
for { set i 1} { $i <= 5 } {incr i} {
    set list $ListOfArrays($i)
    foreach {key} [array names list] {
        puts $key
    }
}

The output is empty...

what is wrong?!

Upvotes: 0

Views: 1074

Answers (2)

Peter Lewerin
Peter Lewerin

Reputation: 13252

As an alternative to the array-based solutions, a solution using dictionaries. I borrow the data from Jerry's answer.

set dict1 {1 a 2 b}
set dict2 {3 c 4 d}
set dict3 {5 e 6 f}
set dict4 {7 g 8 h}
set dict5 {9 i 10 j}

set dicts [list $dict1 $dict2 $dict3 $dict4 $dict5]

foreach dict $dicts {
    foreach key [dict keys $dict] {
        puts $key
    }
}

Unlike arrays, dictionaries can be passed as values and evaluated using $. This means that you can put your five dictionaries in a list and traverse that list with foreach. In the inner loop, each key is printed.

foreach dict $dicts {
    dict for {key -} $dict {
        puts $key
    }
}

is basically the same thing.

Documentation: dict, foreach, list, puts, set

Upvotes: 0

Donal Fellows
Donal Fellows

Reputation: 137557

Tcl's arrays can't be put in a list; they're (collections of) variables, not values. But you can put the names of the arrays in.

array set ListOfArrays {1 array1 2 array2 3 array3 4 array4 5 array5}
for { set i 1} { $i <= 5 } {incr i} {
    upvar 0 $ListOfArrays($i) list
    foreach {key} [array names list] {
        puts $key
    }
}

The upvar 0? It makes a local alias to a variable, and it's great for this sort of thing.

Upvotes: 1

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