MaplePrimes - answers and comments on Question, Multiple files

Multiple files

Robert Israel — Sat, 06 Jun 2009 02:03:49 Z

I think you want something like this:

> for i from 1740 to 1770 do
     Y[i]:= readdata(cat("/Users/humadih/test/",i,".tmp"), 1)
   end do;

This should produce separate lists Y[1740] to Y[1770].

If you want a Matrix with these as rows, you can then do

> Matrix([seq(Y[i],i=1740..1770)]);

Thanks Robert, it

mathgeek — Sat, 06 Jun 2009 02:20:09 Z

Thanks Robert, it worked! why do you have to use for - do loop instead the seq command? is it possible to do it that way? I'm just curious thanks again

for - do vs seq

mathgeek — Sat, 06 Jun 2009 08:41:58 Z

Jakubi, thanks for the comment, I understand the fundamental difference between the two. I was wondering if I can do what Robert did with the seq command. I figured it out! what's cf ? thanks

for - do vs seq

jakubi — Sat, 06 Jun 2009 04:49:10 Z

The 'seq' command creates a sequence of expressions, while the 'for' - 'do' loop creates a repetition of statements, like the assignment statement here (cf ?assignment).

Using seq

Robert Israel — Sun, 07 Jun 2009 11:55:14 Z

Do you mean like this?

> Matrix([seq(readdata(cat("/Users/humadih/test/",i,".tmp"), 1), i = 1740 .. 1770)]);

cf

acer — Sat, 06 Jun 2009 09:21:24 Z

cf. is an abbreviation for the Latin word confer, meaning compare.

You may already have figured out that you can accomplish the assignments using seq and assign. The result (NULL) gets ignored, as the assignments get done as side-effects. It's slick, but not especially good.

> x[1], x[2], x[3] := 1, 2, 3:

> seq( assign(a[i],x[i]), i=1..3 );

> a[1], a[2], a[3];
                                    1, 2, 3

acer