CODEWITHSUNDEEP
regex
Leon Fedotov
Leon Fedotov

Reputation: 7851

Regex: matching up to the first occurrence of a character

I am looking for a pattern that matches everything until the first occurrence of a specific character, say a ";" - a semicolon.

I wrote this:

/^(.*);/

But it actually matches everything (including the semicolon) until the last occurrence of a semicolon.

Upvotes: 618

Views: 1007596

Answers (16)

sleske
sleske

Reputation: 83609

You need

/^[^;]*/

The [^;] is a character class, it matches everything but a semicolon.

^ (start of line anchor) is added to the beginning of the regex so only the first match on each line is captured. This may or may not be required, depending on whether possible subsequent matches are desired.

To cite the perlre manpage:

You can specify a character class, by enclosing a list of characters in [] , which will match any character from the list. If the first character after the "[" is "^", the class matches any character not in the list.

This should work in most regex dialects.

Notes:

  • The pattern will match everything up to the first semicolon, but excluding the semicolon. Also, the pattern will match the whole line if there is no semicolon. If you want the semicolon included in the match, add a semicolon at the end of the pattern.
  • This pattern only works for matching up to the first occurence of a single character. If you want to match up to the first occurence of a (multi-character) string, we've got you covered, too :-). See Matching up to first occurrence of two characters .

Upvotes: 789

utkarsh2299
utkarsh2299

Reputation: 301

I was having the same problem of finding and selecting the text till first occurrence of character in my IDE:

Just use this:

^(.*?)

And append it with the character that you want the text to be selected, i.e., in my case i wanted to change train_0001 to train_1001:

^(.*?)_0

Just did the above and changed the sentence directly in IDE. Hope it helps. Thanks!

Upvotes: 1

Aerodynamika
Aerodynamika

Reputation: 8413

All the answers above match a string if it does not contain the character.

If you want to have match only if the character exists (and no match otherwise), you should use this regex:

/^(.*?);/

Upvotes: 3

Stranger
Stranger

Reputation: 10611

This works for getting the content from the beginning of a line till the first word,

/^.*?([^\s]+)/gm

Upvotes: 2

akshaay
akshaay

Reputation: 1

I faced a similar problem including all the characters until the first comma after the word entity_id. The solution that worked was this in Bigquery:

SELECT regexp_extract(line_items,r'entity_id*[^,]*')

Upvotes: 0

Lonzak
Lonzak

Reputation: 9816

None of the proposed answers did work for me. (e.g. in notepad++) But

^.*?(?=\;)

did.

Upvotes: 24

RJFalconer
RJFalconer

Reputation: 11662

Would;

/^(.*?);/

work?

The ? is a lazy operator, so the regex grabs as little as possible before matching the ;.

Upvotes: 465

mchid
mchid

Reputation: 3109

This will match up to the first occurrence only in each string and will ignore subsequent occurrences.

/^([^;]*);*/

Upvotes: 5

L1amm
L1amm

Reputation: 47

Really kinda sad that no one has given you the correct answer....

In regex, ? makes it non greedy. By default regex will match as much as it can (greedy)

Simply add a ? and it will be non-greedy and match as little as possible!

Good luck, hope that helps.

Upvotes: 2

sPooKee
sPooKee

Reputation: 31

"/^([^\/]*)\/$/" worked for me, to get only top "folders" from an array like:

a/   <- this
a/b/
c/   <- this
c/d/
/d/e/
f/   <- this

Upvotes: 3

poncius
poncius

Reputation: 151

sample text: 

"this is a test sentence; to prove this regex; that is g;iven below"

If for example we have the sample text above, the regex /(.*?\;)/ will give you everything until the first occurence of semicolon (;), including the semicolon: "this is a test sentence;"

Upvotes: 15

Yardboy
Yardboy

Reputation: 2805

This was very helpful for me as I was trying to figure out how to match all the characters in an xml tag including attributes. I was running into the "matches everything to the end" problem with:

/<simpleChoice.*>/

but was able to resolve the issue with:

/<simpleChoice[^>]*>/

after reading this post. Thanks all.

Upvotes: 7

ghostdog74
ghostdog74

Reputation: 342363

this is not a regex solution, but something simple enough for your problem description. Just split your string and get the first item from your array.

$str = "match everything until first ; blah ; blah end ";
$s = explode(";",$str,2);
print $s[0];

output

$ php test.php
match everything until first

Upvotes: 5

Dan Breslau
Dan Breslau

Reputation: 11522

Try /[^;]*/

Google regex character classes for details.

Upvotes: 22

Glenn Slaven
Glenn Slaven

Reputation: 34193

/^[^;]*/

The [^;] says match anything except a semicolon. The square brackets are a set matching operator, it's essentially, match any character in this set of characters, the ^ at the start makes it an inverse match, so match anything not in this set.

Upvotes: 55

Skilldrick
Skilldrick

Reputation: 70819

Try /[^;]*/

That's a negating character class.

Upvotes: 12

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