a regular expression to capture two patterns with a minor difference

Question

A file contains the following types of records, where each record has four entries.

abc, 12:30, love coding, re0*10

cde, informative, "love coding, abcd,ab/cd", 0

The usage scenario is like this, given a file of 1000 records. Each record will be put into a row in the table, the each entry will be put into a corresponding entry. I would like to have a Regex that can help me capture the four entries for each record.

For the first type of record, I can use the following pattern to capture the four entries

 ^([^,]*),([^,]*),([^,]*),([^,]*)$

For the second type of record, I can use

^([^,]*),([^,]*),"([.*])",([^,]*)$

But how to have a single regular expression to capture these two patterns, which can be used to process the whole file.

Possible duplicate of: [Java: splitting a comma-separated string but ignoring commas in quotes](http://stackoverflow.com/questions/1757065/java-splitting-a-comma-separated-string-but-ignoring-commas-in-quotes) - In the top/accepted answer given a regex is given to achieve the behavior you want. — Kevin Cruijssen, Mar 24 '16 at 15:57

score 0 · Answer 1 · answered Mar 24 '16 at 16:11

0

You could use the alternation operator "|".

Like this:

^([^,]*), ([^,]*), (?:(".*")|([^,]*) ), ([^,]*)$

answered Mar 24 '16 at 16:11

Lucas Araujo

1,413
12
22

But one is non-capturing, but I also think @anabhava solution is more correct. – Lucas Araujo Mar 24 '16 at 16:26

score 0 · Accepted Answer · answered Mar 24 '16 at 16:15

0

To be able to match both lines you can use alternation like this:

^("[^"]*"|[^,]*), *("[^"]*"|[^,]*), *("[^"]*"|[^,]*), *("[^"]*"|[^,]*)$

("[^"]*"|[^,]*) in each cell matches either a quoted value or anything that is not a comma. Note that it doesn't take care of unbalanced or escaped quoted strings.

RegEx Demo

answered Mar 24 '16 at 16:15

anubhava

664,788
59
469
547

Hi anubhava, may I know what does **, (right before ("[^"]*"|[^,]*)) used for? – user288609 Mar 24 '16 at 18:43
`, *` matches a comma and then 0 or more spaces after that – anubhava Mar 24 '16 at 18:46

fabian · Answer 3 · 2016-03-24T16:36:14.213

I just post the solution for a single part of the line (the part corresponding to the capturing group, that can be surrounded by quotes). I think you can continue from there yourself

"?((?<=")[^"]*(?=")|(?<!")[^,]*(?!"))"?

This uses lookarounds to take care of the quotes. This way the groups stay the same as in the original regexps

This way the quotes, if there are quotes, are outside the capturing group, but the regex matches only if either there are quotes on both sides of the capturing group ((?<=")[^"]*(?=")) or if there are no quotes on both sides ((?<!")[^,]*(?!")).

a regular expression to capture two patterns with a minor difference

3 Answers3