Subcommand of [dict]. Tests whether a particular key exists in a dictionary (or nested set of dictionaries).
    :   '''dict exists''' ''dict'' ''key'' ?''key …''?

This command does not return an error if ''dict'' isn't actually a dictionary.

----
<<discussion>>
There's a difference in behaviour between tclsh (ActiveTcl) and tclkitsh (tested with both 8.5.11):
======
set theDict [dict create one 1 two 2 three {3 x}]
puts [dict exists $theDict four]
puts [dict exists $theDict three 3]
puts [dict exists $theDict three 4]
puts [dict exists $theDict two y]; <=========== Difference between tclsh and tclkitsh

# tclkitsh8511 dicttest.tcl
0
1
0
missing value to go with key
    while executing
"dict exists $theDict two y"
    invoked from within
"puts [dict exists $theDict two y]"
    (file "dicttest.tcl" line 5)

# tclsh dicttest.tcl
0
1
0
0
======

[DKF]: That'll be a difference between versions due to [https://sourceforge.net/tracker/index.php?func=detail&aid=3475264&group_id=10894&atid=110894%|%Bug 3475264].

<<categories>> Command