Re: Converting {{a,b},{c,d}} to just {a,b},{c,d} (no enclosing parens) ?

*To*: mathgroup at smc.vnet.net*Subject*: [mg28781] Re: Converting {{a,b},{c,d}} to just {a,b},{c,d} (no enclosing parens) ?*From*: "Allan Hayes" <hay at haystack.demon.co.uk>*Date*: Sat, 12 May 2001 20:18:14 -0400 (EDT)*References*: <9di042$kuc@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

The function Level can be useful on nested lists: Level[{{1,2},{{3,4},{{{5,6}},{7,8}}}},{-2}] {{1,2},{3,4},{5,6},{7,8}} To get a sequence: Sequence@@% Sequence[{1,2},{3,4},{5,6},{7,8}] -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565 "aes" <siegman at stanford.edu> wrote in message news:9di042$kuc at smc.vnet.net... > How can I convert a list of pairs, like > > {{a,b},{c,d},{e,f},. . . }} > > into just a sequence of pairs, i.e. > > {a,b}, {c,d}, {e,f}, . . . > > with no outer { }'s? > > Reason for doing this? Want to define a Line in the form > > Line[{pt1, pt2, pt3, pt4, pt5, pt6, . . . . . . }] > > where some of the points, say pt1 through pt4 are individually defined; > but then a sequence, say pt5 through pt20, are defined by a Table; then > pt21, etc are back to individual definitions. > > I know -- I could break these into a sequence of Lines -- but it would > be cleaner if there were a simple way to have one Line[ ] command with > all the points inside it. >