RegEx: Match everything up to the last space without including it - regex

I'd like to match everything in a string up to the last space but without including it. For the sake of example, I would like to match characters I put in bold:
RENATA T. GROCHAL
So far I have ^(.+\s)(.+) However, it matches the last space and I don't want it to. RegEx should work also for other languages than English, as mine does.
EDIT: I didn't mention that the second capturing group should not contain a space – it should be GROCHAL not GROCHAL with a space before it.
EDIT 2: My new RegEx based on what the two answers have provided is: ^((.+)(?=\s))\s(.+) and the RegEx used to replace the matches is \3, \1. It does the expected result:
GROCHAL, RENATa T.
Any improvements would be desirable.

^(.+)\s(.+)
with substitution string:
\2, \1
Update:
Another version that can collapse extra spaces between the 2 capturing groups:
^(.+?)\s+(\S+)$

Use a positive lookahead assertion:
^(.+)(?=\s)
Capturing group 1 will contain the match.

I like using named capturing groups:
rawName = RENATA T. GROCHAL
RegexMatch(rawName, "O)^(?P<firstName>.+)\s(?P<lastName>.+)", match)
MsgBox, % match.lastName ", " match.firstName

Related

Extra groups in regex

I'm building a regex to be able to parse addresses and am running into some blocks. An example address I'm testing against is:
5173B 63rd Ave NE, Lake Forest Park WA 98155
I am looking to capture the house number, street name(s), city, state, and zip code as individual groups. I am new to regex and am using regex101.com to build and test against, and ended up with:
(^\d+\w?)\s((\w*\s?)+).\s(\w*\s?)+([A-Z]{2})\s(\d{5})
It matches all the groups I need and matches the whole string, but there are extra groups that are null value according to the match information (3 and 4). I've looked but can't find what is causing this issue. Can anyone help me understand?
Your regex expression was almost good:
(^\d+\w?)\s([\w*\s?]+).\s([\w*\s?]+)\s([A-Z]{2})\s(\d{5})
What I changed are the second and third groups: in both you used a group inside a group ((\w*\s?)+), where a class inside a group (([\w*\s?]+)) made sure you match the same things and you get the proper group content.
With your previous syntax, the inner group would be able to match an empty substring, since both quantifiers allow for a zero-length match (* is 0 to unlimited matches and ? is zero or one match). Since this group was repeated one or more times with the +, the last occurrence would match an empty string and only keep that.
For this you'll need to use a non-capturing group, which is of the form (?:regex), where you currently see your "null results". This gives you the regex:
(^\d+\w?)\s((?:\w*\s?)+).\s(?:\w*\s?)+([A-Z]{2})\s(\d{5})
Here is a basic example of the difference between a capturing group and a non-capturing group: ([^s]+) (?:[^s]+):
See how the first group is captured into "Group 1" and the second one is not captured at all?
Matching an address can be difficult due to the different formats.
If you can rely on the comma to be there, you can capture the part before it using a negated character class:
^(\d+[A-Z]?)\s+([^,]+?)\s*,\s*(.+?)\s+([A-Z]{2})\s(\d{5})$
Regex demo
Or take the part before the comma that ends on 2 or more uppercase characters, and then match optional non word characters using \W* to get to the first word character after the comma:
^(\d+[A-Z]?)\s+(.*?\b[A-Z]{2,}\b)\W*(.+?)\s+([A-Z]{2})\s(\d{5})$
Regex demo

Capture number between two whitespaces (RegEx)

I have the following data:
SOMEDATA .test 01/45/12 2.50 THIS IS DATA
and I want to extract the number 2.50 out of this. I have managed to do this with the following RegEx:
(?<=\d{2}\/\d{2}\/\d{2} )\d+.\d+
However that doesn't work for input like this:
SOMEDATA .test 01/45/12 2500 THIS IS DATA
In this case, I want to extract the number 2500.
I can't seem to figure out a regex rule for that. Is there a way to extract something between two spaces ? So extract the text/number after the date until the next whitespace ? All I know is that the date will always have the same format and there will always be a space after the text and then a space after the number I want to extract.
Can someone help me out on this ?
Capture number between two whitespaces
A whitespace is matched with \s, and non-whitespace with \S.
So, what you can use is:
\d{2}\/\d{2}\/\d{2} +(\S+)
^^^
See the regex demo
The 1+ non-whitespace symbols are captured into Group 1.
If - for some reason - you need to only get the value as a whole match, use your lookbehind approach:
(?<=\d{2}\/\d{2}\/\d{2} )\S+
Or - if you are using PCRE - you may leverage the match reset operator \K:
\d{2}\/\d{2}\/\d{2} +\K\S+
^^
See another demo
NOTE: the \K and a capture group approaches allow 1 or more spaces after the date and are thus more flexible.
I see some people helped you already, but if you would want an alternative working one for some reason, here's what works too :)
.+ \d+\/\d+\/\d+ (\d+[\.\d]*)
So the .+ matches anything plus the first space
then the \d+/\d+/\d+ is the date parsing plus a space
the capturing group is the number, as you can see I made the last part optional, so both floating point values and normal values can be matched. Hope this helped!
Proof: https://regex101.com/r/fY3nJ2/1
Just make the fractal part optional:
(?<=\d{2}\/\d{2}\/\d{2} )\d+(?:\.\d+)?
Demo: https://regex101.com/r/jH3pU7/1
Update following clarifications in comments:
To match anything (but space) surrounded by spaces and prepended by date use:
(?<=\d{2}\/\d{2}\/\d{2} )\S+
Demo: https://regex101.com/r/jH3pU7/3
Rather than capture, you can make your entire match be the target text by using a look behind:
(?<=\d\d(\/\d\d){2} )\S+
This matches the first series of non-whitespace that follows a "date like" part.
Note also the reduction in the length of the "date like" pattern. You may consider using this part of the regex in whatever solution you use.

Mixing Lookahead and Lookbehind in 1 Regexp

I'm trying to match first occurrence of window.location.replace("http://stackoverflow.com") in some HTML string.
Especially I want to capture the URL of the first window.location.replace entry in whole HTML string.
So for capturing URL I formulated this 2 rules:
it should be after this string: window.location.redirect("
it should be before this string ")
To achieve it I think I need to use lookbehind (for 1st rule) and lookahead (for 2nd rule).
I end up with this Regex:
.+(?<=window\.location\.redirect\(\"?=\"\))
It doesn't work. I'm not even sure that it legal to mix both rules like I did.
Can you please help me with translating my rules to Regex? Other ways of doing this (without lookahead(behind)) also appreciated.
The pattern you wrote is really not the one you need as it matches something very different from what you expect: text window.location.redirect("=") in text window.location.redirect("=") something. And it will only work in PCRE/Python if you remove the ? from before \" (as lookbehinds should be fixed-width in PCRE). It will work with ? in .NET regex.
If it is JS, you just cannot use a lookbehind as its regex engine does not support them.
Instead, use a capturing group around the unknown part you want to get:
/window\.location\.redirect\("([^"]*)"\)/
or
/window\.location\.redirect\("(.*?)"\)/
See the regex demo
No /g modifier will allow matching just one, first occurrence. Access the value you need inside Group 1.
The ([^"]*) captures 0+ characters other than a double quote (URLs you need should not have it). If these URLs you have contain a ", you should use the second approach as (.*?) will match any 0+ characters other than a newline up to the first ").

Greedy/non-greedy quantifiers in ABAP regular expressions

I would like to extract 2 things from this string: | 2013.10.10 FEL felsz
regex -> Date field -> the needed value will be only the 2013.10.10 (in this case)
regex -> String between 2013.10.10 and felsz string -> the needed value will be only the FEL string (in this case).
I tried with the following regexes as with not too much success:
(.*?<p/\s>.*?)(?=\s)
(.*?<p/("[0-9]+">.*?)(?=\s)
Do you have any suggestions?
As mentioned in comments, since ABAP doesn't allow non-greedy match with *?, if you can count on felsz occurring only immediately after the second portion you want to match you could use:
(\d{4}\.\d\d\.\d\d) (.*) felsz
(PS: Invalidated first answer: in non-ABAP systems where *? is supported, the following regex will get both values into submatches. The date will be in submatch 1 and the other value (FEL in this case) will be in submatch 2 : `(\d{4}.\d\d.\d\d) (.*?) felsz)
Is "felsz" variable? Can the white space vary? Can your date format vary? If not:
\| (\d{4}\.\d{2}\.\d{2}) (.*?) felsz
Otherwise:
\|\s+?(\d{4}\.\d{2}\.\d{2})\s+?(.*?)\s+?[a-z]+
Then access capture groups 1/2.
The regex
\d+\.\d+\.\d+
matches 2013.10.10 in the given string. Explanation and demonstration: http://regex101.com/r/bL7eO0
(?<=\d ).*(?= felsz)
should work to match FEL. Explanation and demonstration: http://regex101.com/r/pV2mW5
If you want them in capturing groups, you could use the regex:
\| (\d+\.\d+\.\d+) (.+?) .*
Explanation and demonstration: http://regex101.com/r/rQ6uU4
How about:
(?:\d+\.\d+\.\d+\s)(.*)\s See it in action.
This matches FEL
Some things I took for granted:
the date always comes first and is a mix of numbers and periods
the date is always followed by a space
the word to capture is always followed by a space
the word to capture never contains a space
Assuming that FEL is always a single word (that is, delimited by a space), you could use the following expression:
(\d{4}\.\d\d\.\d\d) ([^\s]+) (.*)

Matching on repeated substrings in a regex

Is it possible for a regex to match based on other parts of the same regex?
For example, how would I match lines that begins and end with the same sequence of 3 characters, regardless of what the characters are?
Matches:
abcabc
xyz abc xyz
Doesn't Match:
abc123
Undefined: (Can match or not, whichever is easiest)
ababa
a
Ideally, I'd like something in the perl regex flavor. If that's not possible, I'd be interested to know if there are any flavors that can do it.
Use capture groups and backreferences.
/^(.{3}).*\1$/
The \1 refers back to whatever is matched by the contents of the first capture group (the contents of the ()). Regexes in most languages allow something like this.
You need backreferences. The idea is to use a capturing group for the first bit, and then refer back to it when you're trying to match the last bit. Here's an example of matching a pair of HTML start and end tags (from the link given earlier):
<([A-Z][A-Z0-9]*)\b[^>]*>.*?</\1>
This regex contains only one pair of parentheses, which capture the string matched by [A-Z][A-Z0-9]* into the first backreference. This backreference is reused with \1 (backslash one). The / before it is simply the forward slash in the closing HTML tag that we are trying to match.
Applying this to your case:
/^(.{3}).*\1$/
(Yes, that's the regex that Brian Carper posted. There just aren't that many ways to do this.)
A detailed explanation for posterity's sake (please don't be insulted if it's beneath you):
^ matches the start of the line.
(.{3}) grabs three characters of any type and saves them in a group for later reference.
.* matches anything for as long as possible. (You don't care what's in the middle of the line.)
\1 matches the group that was captured in step 2.
$ matches the end of the line.
For the same characters at the beginning and end:
/^(.{3}).*\1$/
This is a backreference.
This works:
my $test = 'abcabc';
print $test =~ m/^([a-z]{3}).*(\1)$/;
For matching the beginning and the end you should add ^ and $ anchors.