Restructure CSV data with Notepad++, Regex - regex

Question

I have a CSV file with following headers and (sample) data:
StopName,RouteName,Travel_Direction,Latitude,Longitude
StreetA # StreetB,1 NameA,DirectionA,Lat,Long
StreetC # StreetD,1 NameA,DirectionA,Lat,Long
...
StreetE # StreetF,1 NameA,DirectionB,Lat,Long
StreetG # StreetH,1 NameA,DirectionB,Lat,Long
...
StreetI # StreetJ,2 NameB,DirectionC,Lat,Long
StreetK # StreetL,2 NameB,DirectionC,Lat,Long
...
StreetM # StreetN,2 NameB,DirectionD,Lat,Long
StreetO # StreetP,2 NameB,DirectionD,Lat,Long
.
.
.
I am wanting to use regex (currently in Notepad++) to get the following results:
1 NameA - DirectionA=[[StreetA # StreetB,[Lat,Long]], [StreetC # StreetD,[Lat,Long]], ...]
1 NameA - DirectionB=[[StreetD # StreetE,[Lat,Long]], [StreetF # StreetG,[Lat,Long]], ...]
2 NameB - DirectionC=[[StreetH # StreetI,[Lat,Long]], [StreetJ # StreetK,[Lat,Long]], ...]
2 NameB - DirectionD=[[StreetL # StreetM,[Lat,Long]], [StreetN # StreetO,[Lat,Long]], ...]
.
.
.
With the Regex and Substitution,
RgX: ^([^,]*),([^,]*),([^,]*),(.*)
Sub: $2 - $3=[$1,[\4]]
Demo: https://regex101.com/r/gS9hD6/1
I have gotten this far:
1 NameA - DirectionA=[StreetA # StreetB,[Lat,Long]]
1 NameA - DirectionA=[StreetC # StreetD,[Lat,Long]]
1 NameA - DirectionB=[StreetE # StreetF,[Lat,Long]]
1 NameA - DirectionB=[StreetG # StreetH,[Lat,Long]]
2 NameB - DirectionC=[StreetI # StreetJ,[Lat,Long]]
2 NameB - DirectionC=[StreetK # StreetL,[Lat,Long]]
2 NameB - DirectionD=[StreetM # StreetN,[Lat,Long]]
2 NameB - DirectionD=[StreetO # StreetP,[Lat,Long]]
In a new regex, I tried splitting the above result on "=", but didn't know where to go from there.
I think one way to get the desired results would be to keep first unique instance of what's before "=", replace new line with "," and enclose it with a [..] to make it an array form.
Edit:
There are about 10k stops (total), but only about 100 unique routes.
Edit 2: (maybe I am asking for too many changes now)
For first regex:
What if I want to use "\n" instead of "="?
At beginning of 2nd regex replacement,
What if I have only RouteName and StopName columns, like this: 1
NameA - DirectionA=[StreetA # StreetB, ...]?
Similarly, what if I only have RouteName and Coordinates, like this:
1 NameA - DirectionA=[[Lat,Long]]?

Answer 1

Steps
1. First replacement:
Find what: ^([^,]*),([^,]*),([^,]*),(.*)
Replace with: \2 - \3=[[\1,[\4]]]
Replace All
2. Second replacement:
Find what: ^[\S\s]*?^([^][]*=)\[\[.*\]\]\K\]\R\1\[(.*)\]$
Replace with: , \2]
Replace All
3. Repeat step 2 until there are no more occurences.
This means that if there are 100 instances (Stops) for the same key (Route - Direction pair), you will have to click Replace All 7 times (ceiling(log2(N))).
Description
I modified your regex in step 1 to add an extra pair of brackets that will enclose the whole set.
For step 2, it finds a pair of lines for the same Direction, appending the last to the previous one.
^[\S\s]*?^([^][]*=) #Group 1: captures "1 NameA - DirA="
\[\[.*\]\] #matches the set of Stops - "[[StA # StB,[Lat,Long]], ..."
\K #keeps the text matched so far out of the match
\]\R #closing "]" and newline
\1 #match next line (if the same route)
\[(.*)\]$ #and capture the Stop (Group 2)
regex101 Demo for step 1
regex101 Demo for step 2

Answer 2

Try this one
I checked it with mobile notepad no error.
Find what:
(s.+#\s\w+),(\d{1,} \w+),(\w+),(.+)
Replace with:
\2 - \3=[[\1,[\4],...]]