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From: RodionGork <rodiongork@github.com>
Newsgroups: comp.lang.tcl
Subject: Array get element with default (no error if not exist)
Date: Fri, 16 Aug 2024 07:10:30 +0000
Organization: novaBBS
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Hi Friends!

Still making my first feeble steps in TCL so please excuse me if this is
naive or was asked multiple times.

Attempt to fetch by non-existing key in "associative array" results in
error, e.g.

set a(1) 5
puts $a(2) ;# yields error

the workaround seems to be [info exists ::a(2)] which feels a bit remote
from other "array" commands.

Is there some motivation why some command for get-with-default is not
implemented, e.g.

puts [array peek $a 2 "default value"]

Popular use-case for this would be creating map where elements are
updated (like counter of words etc) - though I found this is cleverly
covered by "incr" and "append" commands properly behaving
when element to be incremented or appended does not exist yet.

But I suspect there are other situations when such a command may be
handy.

Also why [array exists ...] command does not exist (while [dict exists
...] does)? Perhaps there is something about no good syntax for it due
to how arrays are implemented?

-- 
to email me substitute github with gmail please