Re: extract elements from a list

*Subject*: [mg2862] Re: extract elements from a list*From*: sch at mitre.org ("Stuart C. Schaffner")*Date*: 30 Dec 1995 03:40:42 -0600*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: The MITRE Corp.*Sender*: daemon at wri.com

Dave Wagner has already ably answered part of your query, but I thought I would add a few comments. Yes, you can stick to the FORTRAN subset of Mathematica, but it is often easier to make at least limited use of the other features of the language. Reformulate your problem, as follows: Let x be a list of real numbers. We need a list y that is the same size as x, but where if element i of x is a then the corresponding element of y should be Line[ { { 5, 25 }, { a, a^2 } } ]. Mathematically, this is a mapping. Then Show[ Graphics[ y ] ]. The following should do this: x = { 5, 5.5, 5.4, 5.3 }; makeLine[ x_ ] := Line[ { { 5, 25 }, { x, x^2 } } ]; y = Map[ makeLine, x ]; Show[ Graphics[ y ] ]; If you like one-liners, this also works: Show[ Graphics[ Line[ { { 5, 25 }, { #, #^2 } } ]& /@ x ] ] Here I have used the & operator to make an inline function declaration and have used the /@ abbreviation for the Map function. Good luck and keep trying.