CODEWITHSUNDEEP
arrayslisttcl
Harshad_Dinfi
Harshad_Dinfi

Reputation: 99

tcl Making single list from sublist

Converting List of list into single list. for example:

List1 {1 2 {3 4 5} 6 7 {8} 9 10 {{11 12} 13} 14 {15} 16 {{{{17} 18} 19} 20} 21 22 {23} 24 25}
convert to
List1 { 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25}

How to convert it??

Upvotes: 0

Views: 990

Answers (2)

glenn jackman
glenn jackman

Reputation: 246807

With tcllib:

package require struct::list
set List1 {1 2 {3 4 5} 6 7 {8} 9 10 {{11 12} 13} 14 {15} 16 {{{{17} 18} 19} 20} 21 22 {23} 24 25}
puts [struct::list flatten -full $List1]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Documentation

Upvotes: 1

Donal Fellows
Donal Fellows

Reputation: 137567

Provided the leaves are simple words (e.g., letters, numbers, periods, but absolutely no Tcl metacharacters) it's fairly simple with join:

set s {1 2 {3 4 5} 6 7 {8} 9 10 {{11 12} 13} 14 {15} 16 {{{{17} 18} 19} 20} 21 22 {23} 24 25}
while {[set t [join $s]] ne $s} {set s $t}
puts $s
# => 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

To see how this works, try putting a puts inside the loop, as in this interactive session:

% while {[set t [join $s]] ne $s} {
    puts $t
    set s $t
}
1 2 3 4 5 6 7 8 9 10 {11 12} 13 14 15 16 {{{17} 18} 19} 20 21 22 23 24 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 {{17} 18} 19 20 21 22 23 24 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 {17} 18 19 20 21 22 23 24 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Note that this will not work if you produce an invalid list at any point during the expansion, hence why it is important to avoid metacharacters (especially \, { and }). It's also not usual to do this sort of thing in production code; needing it is usually an indication of something elsewhere having gone wrong.

Upvotes: 0

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