http://www.purl.org/tcl/home/man/tcl8.4/TclCmd/lindex.htm
lindex list index
Treats its first argument as a Tcl list, returning the index'th element (where index must be an integer if numeric) from it. The index numbers begin with 0 (zero). If the index is negative or greater than or equal to the number of elements in list, an empty string is returned.
If instead of an integer, the string end is provided, the last element of the list is returned. You can use end- integer to offset from the last element.
See also list, lappend, linsert, llength, lrange, lreplace, lsearch, lsort .
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