如何将所有内容匹配到字符的第二次出现？

Question

So my string looks like this:

Basic information, advanced information, super information, no information

I would like to capture everything up to second comma so I get:

Basic information, advanced information

What would be the regex for that?

I tried: (.*,.*), but I get

Basic information, advanced information, super information,

Answer 1

This will capture up to but not including the second comma:

[^,]*,[^,]*

English translation:

• [^,]* = as many non-comma characters as possible

• , = a comma

• [^,]* = as many non-comma characters as possible

[...] is a character class. [abc] means "a or b or c", and [^abc] means anything but a or b or c.

Answer 2

You could try ^(.*?,.*?), The problem is that .* is greedy and matches maximum amount of characters. The ? behind * changes the behaviour to non-greedy.

You could also put the parenthesis around each .*? segment to capture the strings separately if you want.

Answer 3

I would take a DRY approach, like this:

^([^,]*,){1}[^,]*

This way you can match everything until the n occurrence of a character without repeating yourself except for the last pattern.

Although in the case of the original poster, the group and repetition of the group is useless I think this will help others that need to match more than 2 times the pattern.

Explanation:

• ^ From the start of the line
• ([^,]*,) Create a group matching everything except the comma character until it meet a comma.
• {1} Count the above pattern (the number of time you need)-1. So if you need 2 put 1, if you need 20 put 19.
• [^,] * Repeat the pattern one last time without the tailing comma.

Answer 4

Try this approach:

(.*?,.*?),.*

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