Almost all variables in Tcl are held as strings ... if you use integers and stirings in calculations such as expr and incr. the strings are converted back and forth intergally. Lists, too, are held as strings of characters in which chunks of string are counted / taken out as being elements in the list. Here's an example setting up a list ... and then reporting the length as a list (where it contains two values), and as a string (where it contains 15 letters).

  % set daze "Monday Chewsday"
  Monday Chewsday
  % puts daze
  daze
  % puts $daze
  Monday Chewsday
  % put [string length $daze]
  15
  % put [llength $daze]
  2
  %

Note my use of almost - Tcl's arrays are NOT held as simple strings - and that does make a difference (later in Tcl course we'll take a look at this)
(written 2015-03-11)

 T206 - Tcl/Tk - Lists
  [144] Tcl sandwich - lists in Tcl - (2004-12-08)
  [463] Splitting the difference - (2005-10-13)
  [781] Tcl - lappend v concat - (2006-06-27)
  [1282] Stringing together Tcl scripts - (2007-07-29)
  [1283] Generating traffic for network testing - (2007-07-29)
  [1334] Stable sorting - Tcl, Perl and others - (2007-09-06)
  [1402] Tcl - append v lappend v concat - (2007-10-23)
  [1405] Sorting in Tcl - lists and arrays - (2007-10-24)
  [1601] Replacing the last comma with an and - (2008-04-04)
  [2468] What are Tcl lists? - (2009-10-22)
  [2472] split and join in tcl and expect - (2009-10-23)
  [3285] Extracting data from a string / line from file - Tcl - (2011-05-10)
  [3394] The difference between lists and strings - Tcl - (2011-08-16)
  [3415] User defined sorting and other uses of callbacks in Tcl and Tk - (2011-09-02)
  [3582] Tcl collections - lists, dicts and array - (2012-01-16)
  [3583] Expanding a list of parameters in Tcl - {*} and eval - (2012-01-17)
  [3618] lists and struct::list in Tcl - Introduction to struct::list and examples - (2012-02-18)
  [4209] Lists in Tcl - fundamentals in a commented source code example - (2013-11-16)
  [4455] Working out distance between places, using OS grid references and a program in Tcl - (2015-03-11)

T205 - Tcl/Tk - String Handling in Tcl
  [404] How to check that a string contains a number in Tcl - (2005-08-06)
  [779] The fragility of pancakes - and better structures - (2006-06-26)
  [943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
  [1403] Square Bracket protection in Tcl - (2007-10-23)
  [1410] Tcl / regsub - changing a string and using interesting bits - (2007-10-27)
  [3192] Tcl - Some example of HOW TO in handling data files and formats - (2011-03-04)
  [3576] Tcl - apparently odd behaviour of string trimleft - (2012-01-13)
  [4205] Regular Expression Substitution - Tcl - (2013-11-12)

Back to Tcl variable names - no real limits!

Previous and next or Horse's mouth home

Forward to Working out distance between places, using OS grid references and a program in Tcl

A new Tcl/tk example - a window to show system status
Test framework for TCL - Tcltest - some examples
Objects in Tcl - iTcl - updated first steps example
Everything is a string - even a list
Tcl variable names - no real limits!
Binary data handling - Python and Perl
Running an operating system command from your Python program - the new way with the subprocess module
Deciding whether to use parameters, conditional statements or subclasses
Spike solution, refactoring into encapsulated object methods - good design practise