I am trying to use Regex to pull the value from between the second set of commas. That has the letter S in the in beginning word.
(?<=S,[^,],)[^,] (?=,)
Above is the closest I can get. It will give the value I am looking for on the BS and CS lines. I was thinking the [^'] in the look behind would get(exclude) all the characters between the first set of commas.
BB,21,1.750000,0.000000,
AS,21.5,3.250000,-0.187500
BS,21,3.250000,-0.187500
CS, ,1.750000,-0.375000
DS,1,30.375000,-0.375000
QA,aa,30.375000,-0.375000
Looking for more than just the answer would really like an explanation so I can learn from it.
CodePudding user response：
You can repeat the character class in the lookbehind at the beginning, but in this case "value from between the second set of commas" is literally 2 comma's to the left of the current value that you are matching.
The S is the last value before the comma, and it can have multiple matches as there are no anchors.
(?<=S,[^,]*,)[^,] (?=,)
If the lines start with only uppercase chars A-Z, you could match at least a single S char in that first part
(?<=^[A-RT-Z]*S[A-Z]*,[^,\n]*,)[^,\n] (?=,)
The pattern matches:
(?<=Positive lookbehind, assert that to the left is^Start of string[A-RT-Z]*Match optional chars A-Z without SS[A-Z]*Match S and optional chars A-Z,[^,\n]*,Match 2 times a comma
)Close the lookbehing[^,\n]Match 1 chars other than a comma or newline(?=,)Assert a comma to the right