Watch[...] is a helper function for watching a list of variables or other functions inside a Module[...] during programming or troubleshooting.

Goal Style Row[...] separator so that printed values print apart with distinctively styled separator between items.

Two Coding Attempts

For first attempt (watch1[...]) separator works but does not style separator. For second attempt (watch2[...]) separator is itself styled but kernel complains by reacting with error codes and nothing else works.

list = {a, b, c};

Separator = ToString[Style[" | ", Darker[Green], Bold, 12]];
watch1[list_] := 
    Table[ToString[list[[i]]] <> Separator, {i, Length[list]}]]];

watch2[list_] := 
    Table[ToString[list[[i]]] <> 
      Style[" | ", Darker[Green], Bold, 12], {i, Length[list]}]]];

Specific Request

Please help by correcting code so that it works as cited in Goal.


1 Answer 1



list = {a, b, c};
Separator = Style[" | ", Darker[Green], Bold, 12];
Row[Flatten@ Table[  {ToString[list[[i]]], Separator}, {i, Length[list]}]]

Mathematica graphics


 Row[Flatten[{ToString[#], Separator} & /@ list]]

Mathematica graphics

Thanks to Bob Hanlon suggestion, Riffle might be better way to go about this so no extra separator at end. The list command above adds | at the end, which OP does not want.

  result = Row[Riffle[list, Separator]]

Mathematica graphics

  • $\begingroup$ thank you for helping me again and again :) $\endgroup$ May 18, 2020 at 0:51
  • 2
    $\begingroup$ watch[list_] := Row@Riffle[list, Separator]; watch[list] $\endgroup$
    – Bob Hanlon
    May 18, 2020 at 0:53
  • $\begingroup$ @Nasser i have one more question: why does it print an extra separator (after last item in list)? how could i stop that behavior? $\endgroup$ May 18, 2020 at 1:26
  • $\begingroup$ @BobHanlon thank you. i shall use your solution as it does not print an extra separator like Nasser's very generous but slightly buggy solution. $\endgroup$ May 18, 2020 at 1:29
  • 1
    $\begingroup$ @JulesManson it might be better in this case to use Riffle like Bob suggested if you do not want seperator at end. $\endgroup$
    – Nasser
    May 18, 2020 at 1:31

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