Deduct "New List" with "new Value" only for some "specific Tag", from Old List, using "List Comprehension".

[Papa Tana]

I had to do it like below:

T = [{a,1}, {length,24568}, {b,2}, {c,3}, {length, 54741}].

WithoutLength = [ {Tag, Value} || {Tag, Value} <-T, Tag/= length].
HowManyLength = length([ {Tag, Value} || {Tag, Value} <-T, Tag== length]).
Extra = lists:duplicate(HowManyLength, {length, 255}).

>NewT = [WithoutLength | Extra ].
[[{a,1},{b,2},{c,3}],{length,255},{length,255}]

Not really the expected result, yes all values of tag length are
replaced, but not in the right order.