2
$\begingroup$

I am very new to mathematica. I am trying to generate list of number sequence. I want to make 6 sequences. 1 - 10, 10 - 100, 100 - 1 000, 1 000 - 10 000, 10 000 - 100 000. All reversed. Is there any elegant to way how to approach that? I am trying to figure it out using documentation, but I can't. Thanks

$\endgroup$
4
  • 1
    $\begingroup$ Are you looking for Range, i.e. something like this: Range[10, 1, -1]? You may also be interested in PowerRange, and combine it with Range. $\endgroup$ – MarcoB Nov 11 '19 at 22:58
  • 1
    $\begingroup$ seqs = Range[10^Range[0, 4], 10^Range[1, 5]]. Then seqs[[1]] will be your first sequence, seqs[[2]] the second... Reverse/@seq will reverse them. rseqs=Range[10^Range[1, 5], 10^Range[0, 4], -1] will generate them already reversed. $\endgroup$ – ciao Nov 11 '19 at 23:02
  • $\begingroup$ Table[Range[10^(n + 1), 10^n, -10^n], {n, 0, 4}] Change the steps to -1 if that is what you actually want. $\endgroup$ – Bob Hanlon Nov 12 '19 at 1:21
  • $\begingroup$ Thanks for all the help. It helped me. :] $\endgroup$ – tobiasekll Nov 12 '19 at 13:00
1
$\begingroup$

The following uses a combination of Range and PowerRange:

Reverse /@ Range @@@ Partition[PowerRange[100000], 2, 1]

Here is an example of output (shortened using Shallow):

{{10, 9, 8, 7, 6, 5, 4, 3, 2, 1}, 
 {100, 99, 98, 97, 96, 95, 94, 93, 92, 91, <<81>>}, 
 {1000, 999, 998, 997, 996, 995, 994, 993, 992, 991, <<891>>}, 
 {10000, 9999, 9998, 9997, 9996, 9995, 9994, 9993, 9992, 9991, <<8991>>}, 
 {100000, 99999, 99998, 99997, 99996, 99995, 99994, 99993, 99992, 99991, <<89991>>}, 
}
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.