I have strings that look like some text - other text and I need to delete everything before and including the hyphen - and the space after it
But do to typos I might have :
some text -other text or some text- other text or some text-other text or double spaces instead of single spaces
I am using RegEx ^.*\s+\-\s+ and this works for some text - other text with single or multiple spaces before and after the -
But for the other possibilities where the whitespace is missing, I have used two or so I have ^.*\s+\-\s+|.*\-\s|.*\-
Is there a more concise patter that does not use multiple ors for this?
Thank you for any help on this
https://regex101.com/r/TNU7i6/1
Instead of using an alternation with 3 patterns, you might use a pattern to match all except the -, then match the - and optional whitespace chars.
^[^-]*-\s*
Regex demo
If there should be a non whitespace char following, and a lookahead is supported:
^[^-]*-\s*(?=\S)
^ Start of string
[^-]*- Match 0+ times any char except -, then match -
\s* Match optional whitespace chars
(?=\S) Positive lookahead, assert a non whitespace char to the right
Regex demo
Note that \s and the negated character class [^-] can also match a newline.
1st solution: With your shown samples, please try following.
^.*?\s+\S+\s?-\s*(.*)$
OR
^.*?\s+\S+\s*-\s*(.*)$
Online demo for above regex
2nd solution: You could use \K option too to forget matched regex part, in that case try:
^.*?\s+\S+\s?-\s*\K.*$
OR
^.*?\s+\S+\s*-\s*\K.*$
Online demo for above regex
1st solution explanation:
^.*?\s+ ##From starting of value matching till 1st occurrence of space(s).
\S+\s? ##Matching 1 or more non-space occurrences followed by optional space here.
-\s* ##Matching - followed by optional space.
(.*)$ ##Matching everything till last of value.
2nd solution explanation:
^.*?\s+ ##Matching everything till 1st space occurrence(s) from starting of value.
\S+\s? ##Matching non spaces 1 or more occurrences followed by space optional.
-\s*\K ##Matching - followed by spaces(0 or more occurrences) and \K will discard all previous matched values(so that we can match exact values as per output).
.*$ ##Matching everything after previously matched values(which is discarded by \K).
Related
I am trying to solve http://play.inginf.units.it/#/level/10
I have some strings as follows:
title={AUTOMATIC ROCKING DEVICE},
author={Diaz, Navarro David and Gines, Rodriguez Noe},
year={2006},
title={The sitting position in neurosurgery: a retrospective analysis of 488 cases},
author={Standefer, Michael and Bay, Janet W and Trusso, Russell},
journal={Neurosurgery},
title={Fuel cells and their applications},
author={Kordesch, Karl and Simader, G{"u}nter and Wiley, John},
volume={117},
I need to match the names in bold. I tried the following regex:
(?<=author={).+(?=})
But it matches the entire string inside {}. I understand why is it so but how can I break the pattern with and?
It took me a little while to get the samples to show up in your link. What about:
(?:^\s*author={|\G(?!^) and )\K(?:(?! and |},).)+
See an online demo
(?:^\s*author={|\G(?!^) and ) - Either match start of a line followed by 0+ whitespace chars and literally match 'author={` or assert position at end of previous match but negate start-line;
\K - Reset starting point of reported match;
(?:(?! and |},).)+ - Match any if it's not followed by ' and ' or match a '}' followed by a comma.
Above will also match 'others' as per last sample in linked test. If you wish to exclude 'others' then maybe add the option to the negated list as per:
(?:^\s*author={|\G(?!^) and )\K(?:(?! and |},|\bothers\b).)+
See an online demo
In the comment section we established above would not work for given linked website. Apparently its JS based which would support zero-width lookbehind. Therefor try:
(?<=\bauthor={(?:(?!\},).*?))\b[A-Z]\S*\b(?:,? [A-Z]\S*\b)*
See the demo
(?<= - Open lookbehind;
\bauthor={ - Match word-boundary and literally 'author={';
(?:(?!\},).*?)) - Open non-capture group to match a negative lookahead for '},' and 0+ (lazy) characters. Close lookbehind;
\b[A-Z]\S*\b - Match anything between two word-boundaries starting with a capital letter A-Z followed by 0+ non-whitespace chars;
(?:,? [A-Z]\S*\b)* - A 2nd non-capture group to keep matching comma/space seperated parts of a name.
If using a lookbehind assertion is supported and matching word characters, you might use:
(?<=\bauthor={[^{}]*(?:{[^{}]*}[^{}]*)*)[A-Z][^\s,]*,(?:\s+[A-Z][^\s,]*)+\b
Explanation
(?<= Postive lookahead, assert that to the left of the current position is
\bauthor={ Match author={ preceded by a word boundary
[^{}]*(?:{[^{}]*}[^{}]*)* Match optional chars other than { } or match {...}
) Close the lookbehind
[A-Z] Match an uppercase char A-Z
[^\s,]*, Optionally match non whitespace chars except , and then match ,
(?: Non capture group to repeat as a whole part
\s+[A-Z][^\s,]* Match 1+ whitespace chars, uppercase char A-Z, optional non whitespace chars except ,
)+ Close the non capture group and repeat it 1 or more times
\b a word boundary
See a regex101 demo.
Details={
AwsEc2SecurityGroup={GroupName=m.com-rds, OwnerId=123, VpcId=vpc-123,
IpPermissions=[{FromPort=3306, ToPort=3306, IpProtocol=tcp, IpRanges=[{CidrIp=1.1.1.1/32}, {CidrIp=2.2.2.2/32}, {CidrIp=0.0.0.0/0}, {CidrIp=3.3.3.3/32}],
UserIdGroupPairs=[{UserId=123, GroupId=sg-123abc}]}], IpPermissionsEgress=[{IpProtocol=-1, IpRanges=[{CidrIp=0.0.0.0/0}]}], GroupId=sg-123abc}},
Region=us-east-1, Id=arn:aws:ec2:us-east-1:123:security-group/sg-123abc}]
}
I want to capture exactly arn:aws:ec2:us-east-1:123:security-group/sg-123abc in this example. Generically, I want to capture the value of Id regardless of placement. My current solution is /Details={.*Id=(.*\w)/, but this only works if it's the last object in the data. How can I take into account the following potential scenario:
Id=arn:aws:ec2:us-east-1:123:security-group/sg-123abc, Thing=123abc}]
You have a pattern with 2 times .* which will first match till the end of the line/string (depending on if the dot matches a newline) and it will backtrack to match the last occurrence where this part of the pattern Id=(.*\w) can match.
If you want to use a capture group, you can make the format and the allowed characters a bit more specific:
\bId=(\w+(?:[:\/-]\w+)+)
The pattern in parts
\b A word boundary to prevent a partial word match
Id= Match literally
( Capture group 1
\w+ Match 1+ word chars
(?:[:\/-]\w+)+ Repeat 1+ times either : / - and 1+ word chars
) Close group 1
Regex demo
Or if you know that it starts with Id=arn:
\bId=(arn:[\w:\/-]+)
Regex demo
Note that you don't have to escape the \/ only when the delimiters of the regex are forward slashes, but there is no language tagged.
You can use look-behind to check that there is the Id= prefix, and then match anything that is not a space, comma or closing brace:
(?<=\bId=)[^,}\s]*
I have fields which contain data in the following possible formats (each line is a different possibility):
AAA - Something Here
AAA - Something Here - D
Something Here
Note that the first group of letters (AAA) can be of varying lengths.
What I am trying to capture is the "Something Here" or "Something Here - D" (if it exists) using PCRE, but I can't get the Regex to work properly for all three cases. I have tried:
- (.*) which works fine for cases 1 and 2 but obviously not 3;
(?<= - )(.*) which also works fine for cases 1 and 2;
(?! - )(.+)| - (.+) works for cases 2 and 3 but not 1.
I feel like I'm on the verge of it but I can't seem to crack it.
Thanks in advance for your help.
Edit: I realized that I was unclear in my requirements. If there is a trailing " - D" (the letter in the data is arbitrary but should only be a single character), that needs to be captured as well.
About the patterns that you tried:
- (.*)This pattern will match the first occurrence of - followed by matching the rest of the line. It will match too much for the second example as the .* will also match the second occurrence of -
(?<= - )(.*)This pattern will match the same as the first example without the - as it asserts that is should occur directly to the left
(?! - )(.+)| - (.+) This pattern uses a negative lookahead which asserts what is directly to the right is not (?! - ). As none of the example start with - , the whole line will be matched directly after the negative lookahead due to .+ and the second part after the alternation | will not be evaluated
If the first group of letters can be of varying length, you could make the match either specific matching 1 or more uppercase characters [A-Z]+ or 1+ word characters \w+.
To get a more broad match, you could match 1 or more non whitespace characters using \S+
^(?:\S+\h-\h)?\K\S+(?:\h(?!-\h)\S+)*
Explanation
^ Start of string
(?:\S+\h-\h)? Optionally match the first group of non whitespace chars followed by - between horizontal whitespace chars
\K Clear the match buffer (Forget what is currently matched)
\S+ Match 1+ non whitespace characters
(?: Non capture group
\h(?!-\h) Match a horizontal whitespace char and assert what is directly to the right is not - followed by another horizontal whitespace char
\S+ Match 1+ non whitespace chars
)* Close non capture group and repeat 1+ times to match more "words" separated by spaces
Regex demo
Edit
To match an optional hyphen and trailing single character, you could add an optional non capturing group (?:-\h\S\h*)?$ and assert the end of the string if the pattern should match the whole string:
^(?:\S+\h-\h)?\K\S+(?:\h(?!-\h)\S+)*\h*(?:-\h\S\h*)?$
Regex demo
You may use
^(?:.*? - )?\K.*?(?= - | *$)
^(?:.*?\h-\h)?\K.*?(?=\h-\h|\h*$)
See the regex demo
Details
^ - start of string
-(?:.*? - )? - an optional non-capturing group matching any 0+ chars other than line break chars as few as possible up to the first space-space
\K - match reset operator
.*? - any 0+ chars other than line break chars as few as possible
(?= - | *$) - space-space or 0+ spaces till the end of string should follow immediately on the right.
Note that \h matches any horizontal whitespace chars.
^(?:[A-Z]+ - \K)?.*\S
demo
Since "Something Here" can be anything, there's no reason to specially describe the eventual last letter in the pattern. You don't need something more complicated.
With this pattern I assume that you are not interested by the trailing spaces, that's why I ended it with \S. If you want to keep them, remove the \S and change the previous quantifier to +.
Given a string such as below:
word.hi. bla. word.
I want to construct a regex which will match all "."s preceded by "word" and any other non space character
So, in the above example I would want the the first, second and last dots to be matched.
While matching the first and last dots would be easy with global flag (/(?:word.*)\K./gU), I'm not sure how to construct a regex that would also match the second dot.
Appreciate any pointers.
You might match word and then get all consecutive matches using the \G anchor excluding matching whitespace chars or a dot.
(?:\bword|\G(?!\A))[^.\s]*\K\.
In parts
(?: Non capture group
\bword Match word preceded by a word boundary
| Or
\G(?!\A) Assert the position at the end of the previous match, not at the start
) Close non capture group
[^.\s]* Match 0+ occurrences of any char except . or a whitespace char
\K Clear the match buffer (forget what is matched until now)
\. Match a dot
Regex demo
I need to find words in a string that start with number(i.e digit)
In following string:
1st 2nd 3rd a56b 5th 6th ***7th
The words 1st 2nd 3rd 5th 6th should be returned.
I tried with the regex:
(\b[^ a-zA-Z ^ *]+(th|rd|st|nd))+
But this regex returns the words not starting with alphabets but can't handle the cases when word starts with special characters.
For the current string, you may use a pattern like
(?<!\S)\d+(?:th|rd|st|nd)\b
See the regex demo
The pattern matches:
(?<!\S) - a location at the start of a string or after a whitespace
\d+ - 1 or more digits
(?:th|rd|st|nd) - one of the four alternatives
\b - a word boundary.
If you plan to match any 0+ non-whitespace chars after a digit that is preceded with a whitespace or is at the start of a string, use
(?<!\S)\d\S*
where \S* will match any 0+ non-whitespace chars.
See this regex demo.
NOTE: In case the lookbehind is not supported, replace (?<!\S) with (?:^|\s) and also wrap the rest of the pattern with a capturing group to access the latter later:
(?:^|\s)(\d\S*)
and the value will be in Group 1.
To get word which is starting with number/digit and ending with th/st/nd/rd you can try this.
((?<!\S)(\d+)(th|rd|nd|st))
(?<!\S) detects the word's starting position
\d+ matches 1 or more digits
th|rd|st|nd matches one among those 4.
You can check it here