In maple, how to create a sequence of alternating variables?-CodePudding

I'm quite new to Maple and I would like to create the following list:

U__N := u__1[0], u__2[0], u__1[1], u__2[1], u__1[2], u__2[2], u__1[3], u__2[3], u__1[4], u__2[4], u__1[5], u__2[5]

I came up with the following two options. For both I lack the knowledge for the last step

Option 1

U__N := seq([u__1[k], u__2[k]], k = 0 .. 5)

which gives me a nested list: U__N := [u__1[0], u__2[0]], [u__1[1], u__2[1]], [u__1[2], u__2[2]], [u__1[3], u__2[3]], [u__1[4], u__2[4]], [u__1[5], u__2[5]]. However, now I do not know how to "un-nest" the nested list.

Option 2:

Create two separate lists

U__N2 := seq(u__2[k], k = 0 .. 5 - 1)

which returns U__N1 := u__1[0], u__1[1], u__1[2], u__1[3], u__1[4]

U__N2 := seq(u__2[k], k = 0 .. 5 - 1)

which returns U__N2 := u__2[0], u__2[1], u__2[2], u__2[3], u__2[4]. Now I would like to concatenate/combine these two lists alternatively.

Do you have any suggestions for one of these two options or an alternative solution?

CodePudding user response：

using Flatten gave me the desired solution

CodePudding user response：

I would prefer to create the pair-wise portions and then utilize those directly, than to form the whole list-of-lists and Flatten it.

The special-evaluation rules of the seq command allows for its first argument to not be evaluated until after k attains concrete numeric values.

This allow you to adjust your first method and extract the operands of the pair-wise inner lists, using the op command.

seq(op([u__1[k], u__2[k]]), k = 0 .. 5);

   u__1[0], u__2[0], u__1[1], u__2[1],
   u__1[2], u__2[2], u__1[3], u__2[3],
   u__1[4], u__2[4], u__1[5], u__2[5]

seq([u__1[k], u__2[k]][], k = 0 .. 5);

   u__1[0], u__2[0], u__1[1], u__2[1],
   u__1[2], u__2[2], u__1[3], u__2[3],
   u__1[4], u__2[4], u__1[5], u__2[5]

The trailing [] in [...][] acts like op([...]).