I want to remove all numbers from a paragraph except from some words.
My attempt is using a negative look-ahead:
gsub('(?!ami.12.0|allo.12)[[:digit:]]+','',
c('0.12','1245','ami.12.0 00','allo.12 1'),perl=TRUE)
But this doesn't work. I get this:
"." "" "ami.. " "allo."
Or my expected output is:
"." "" 'ami.12.0','allo.12'
You can't really use a negative lookahead here, since it will still replace when the cursor is at some point after ami.
What you can do is put back some matches:
(ami.12.0|allo.12)|[[:digit:]]+
gsub('(ami.12.0|allo.12)|[[:digit:]]+',"\\1",
c('0.12','1245','ami.12.0 00','allo.12 1'),perl=TRUE)
I kept the . since I'm not 100% sure what you have, but keep in mind that . is a wildcard and will match any character (except newlines) unless you escape it.
Your regex is actually finding every digit sequence that is not the start of "ami.12.0" or "allo.12". So for example, in your third string, it gets to the 12 in ami.12.0 and looks ahead to see if that 12 is the start of either of the two ignored strings. It is not, so it continues with replacing it. It would be best to generalize this, but in your specific case, you can probably achieve this by instead doing a negative lookbehind for any prefixes of the words (that can be followed by digit sequences) that you want to skip. So, you would use something like this:
gsub('(?<!ami\\.|ami\\.12\\.|allo\\.)[[:digit:]]+','',
c('0.12','1245','ami.12.0 00','allo.12 1'),perl=TRUE)
Related
I have the following regex ^(2[0-3]|1?[0-9])?(\:[0-5]?[0-9])?$
8:45 matches, however 08:45 does not.
How can this be re-written to also allow 08:45?
I would also like like to check for either the . or : if possible instead of just the .
As well as "1", also allow "0" at the start of the hours before "20:00":
^(2[0-3]|[01]?[0-9])?(:[0-5]?[0-9])?$
Note that you don't need to escape colons - they have no speacial regex meaning.
Also, since everything is optional, this regex matches a blank string.
If you want to match something, add (?!$) after ^. ^(?!$) is a negative look ahead anchored to start that requires that end of input does not follow the start of input (ie, the input is not zero length).
Please try this regEx.
[0]?\d[:\.]\d\d
which can capture 8:45 08:45 8.45 and 08.45
or click this to see the result.
https://regex101.com/r/tLEqhH/1
Sample input:
___file___name___2000___ed2___1___2___3
DIFFERENT+FILENAME+(2000)+1+2+3+ed10
Desired output (eg, all letters and 4-digit numbers and literal 'ed' followed immediately by a digit of arbitrary length:
file name 2000 ed2
DIFFERENT FILENAME 2000 ed10
I am using:
[A-Za-z]+|[\d]{4}|ed\d+ which only returns:
file name 2000 ed
DIFFERENT FILENAME 2000 ed
I see that there is a related Q+A here:Regular Expression to match specific string followed by number?
eg using ed[0-9]* would match ed#, but unsure why it does not match in the above.
As written, your regex is correct. Remember, however, that regex tries to match its statements from left to right. Your ed\d+ is never going to match, because the ed was already consumed by your [A-Za-z] alternative. Reorder your regex and it'll work just fine:
ed\d+|[a-zA-Z]+|\d{4}
Demo
Nick's answer is right, but because in-order matching can be a less readable "gotcha", the best (order-insensitive) ways to do this kind of search are 1) with specified delimiters, and 2) by making each search term unique.
Jan's answer handles #1 well. But you would have to specify each specific delimiter, including its length (e.g. ___). It sounds like you may have some unusual delimiters, so this may not be ideal.
For #2, then, you can make each search term unique. (That is, you want the thing matching "file" and "name" to be distinct from the thing matching "2000", and both to be distinct from the thing matching "ed2".)
One way to do this is [A-Za-z]+(?![0-9a-zA-Z])|[\d]{4}|ed\d+. This is saying that for the first type of search term, you want an alphabet string which is followed by a non-alphanumeric character. This keeps it distinct from the third search term, which is an alphabet string followed by some digit(s). This also allows you to specify any range of delimiters inside of that negative lookbehind.
demo
You might very well use (just grab the first capturing group):
(?:^|___|[+(]) # delimiter before
([a-zA-Z0-9]{2,}) # the actual content
(?=$|___|[+)]) # delimiter afterwards
See a demo on regex101.com
Lets say I have a string something-123.
I need to get last 5 (or less) characters of it but only up to - if there is one in the string, so the result would be like thing, but if string has no - in it, like something123 then the result would be ng123, and if string is like 123 then the result would be 123.
I know how to mach last 5 characters:
/.{5}$/
I know how to mach everything up to first -:
/[^-]*/
But I can not figure out how to combine them, and to make things worse I need to get the match without extracting it from specific groups and similar advanced regex stuff because I want to use it in SQL Anywhere, please help.
Tank you all for the help, but looks like a complete regex solution is going to be too complicated for my problem, so I did it very simple: SELECT right(regexp_substr('something-123', '[^-]*'), 4).
One option is to group the result:
(.{4})-
Now you have captured the result but without the -.
Or using lookarounds you can:
.{4}(?=-)
which matches any 4 characters that appears before "-".
You can use:
.{5}(?=(?:-[^-]*)?$)
See the regex demo
We match 5 symbols other than a newline only before the last - in the string or at the very end of the string ((?=(?:-[^-]*)?$)). You only need to collect the matches, no need checking groups/submatches.
UPDATE
To match any 1 to 5 characters other than a hyphen before the first hyphen (if present in the string), you can use
([^-]{1,5})(?:(?:-[^-]*)*)?$
See demo. We rely on a lookahead here, that checks if there are -+non-hyphen sequences are after the expected substring.
An faster alternative:
^[^-]*?([^-]{1,5})(?:-|$)
This regex will search for any characters other than - up to 1 to 5 such characters.
Note that here, the value we need is in Group 1.
How about:
(.{5})(?:-[^-]+)?$
The result is in group 1
Try this regex:
(.{1,5})(?:-.*|$)
Group 1 has the result you need
demo
I am re-phrasing my question to clear confusions!
I want to match if a string has certain letters for this I use the character class:
[ACD]
and it works perfectly!
but I want to match if the string has those letter(s) 2 or more times either repeated or 2 separate letters
For example:
[AKL] should match:
ABCVL
AAGHF
KKUI
AKL
But the above should not match the following:
ABCD
KHID
LOVE
because those are there but only once!
that's why I was trying to use:
[ACD]{2,}
But it's not working, probably it's not the right Regex.. can somebody a Regex guru can help me solve this puzzle?
Thanks
PS: I will use it on MYSQL - a differnt approach can also welcome! but I like to use regex for smarter and shorter query!
To ensure that a string contains at least two occurencies in a set of letters (lets say A K L as in your example), you can write something like this:
[AKL].*[AKL]
Since the MySQL regex engine is a DFA, there is no need to use a negated character class like [^AKL] in place of the dot to avoid backtracking, or a lazy quantifier that is not supported at all.
example:
SELECT 'KKUI' REGEXP '[AKL].*[AKL]';
will return 1
You can follow this link that speaks on the particular subject of the LIKE and the REGEXP features in MySQL.
If I understood you correctly, this is quite simple:
[A-Z].*?[A-Z]
This looks for your something in your set, [A-Z], and then lazily matches characters until it (potentially) comes across the set, [A-Z], again.
As #Enigmadan pointed out, a lazy match is not necessary here: [A-Z].*[A-Z]
The expression you are using searches for characters between 2 and unlimited times with these characters ACDFGHIJKMNOPQRSTUVWXZ.
However, your RegEx expression is excluding Y (UVWXZ])) therefore Z cannot be found since it is not surrounded by another character in your expression and the same principle applies to B ([ACD) also excluded in you RegEx expression. For example Z and A would match in an expression like ZABCDEFGHIJKLMNOPQRSTUVWXYZA
If those were not excluded on purpose probably better can be to use ranges like [A-Z]
If you want 2 or more of a match on [AKL], then you may use just [AKL] and may have match >= 2.
I am not good at SQL regex, but may be something like this?
check (dbo.RegexMatch( ['ABCVL'], '[AKL]' ) >= 2)
To put it in simple English, use [AKL] as your regex, and check the match on the string to be greater than 2. Here's how I would do in Java:
private boolean search2orMore(String string) {
Matcher matcher = Pattern.compile("[ACD]").matcher(string);
int counter = 0;
while (matcher.find())
{
counter++;
}
return (counter >= 2);
}
You can't use [ACD]{2,} because it always wants to match 2 or more of each characters and will fail if you have 2 or more matching single characters.
your question is not very clear, but here is my trial pattern
\b(\S*[AKL]\S*[AKL]\S*)\b
Demo
pretty sure this should work in any case
(?<l>[^AKL\n]*[AKL]+[^AKL\n]*[AKL]+[^AKL\n]*)[\n\r]
replace AKL for letters you need can be done very easily dynamicly tell me if you need it
Is this what you are looking for?
".*(.*[AKL].*){2,}.*" (without quotes)
It matches if there are at least two occurences of your charactes sorrounded by anything.
It is .NET regex, but should be same for anything else
Edit
Overall, MySQL regular expression support is pretty weak.
If you only need to match your capture group a minimum of two times, then you can simply use:
select * from ... where ... regexp('([ACD].*){2,}') #could be `2,` or just `2`
If you need to match your capture group more than two times, then just change the number:
select * from ... where ... regexp('([ACD].*){3}')
#This number should match the number of matches you need
If you needed a minimum of 7 matches and you were using your previous capture group [ACDF-KM-XZ]
e.g.
select * from ... where ... regexp('([ACDF-KM-XZ].*){7,}')
Response before edit:
Your regex is trying to find at least two characters from the set[ACDFGHIJKMNOPQRSTUVWXZ].
([ACDFGHIJKMNOPQRSTUVWXZ]){2,}
The reason A and Z are not being matched in your example string (ABCDEFGHIJKLMNOPQRSTUVWXYZ) is because you are looking for two or more characters that are together that match your set. A is a single character followed by a character that does not match your set. Thus, A is not matched.
Similarly, Z is a single character preceded by a character that does not match your set. Thus, Z is not matched.
The bolded characters below do not match your set
ABCDEFGHIJKLMNOPQRSTUVWXYZ
If you were to do a global search in the string, only the italicized characters would be matched:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
I've been having a lot of trouble finding how to write a regex to include certain URLs starting with a specified phrase while excluding another.
We want to include pages that start with:
/womens
/mens
/kids-clothing/boys
/kids-clothing/girls
/homeware
But we want to exclude anything that has /sXXXXXXX in the URL - where the X's are numbers.
I've written this so far to match the below URLs but it's behaving very oddly. Should I be using lookarounds or something?
\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/boys|homeware).*[^s[0-9]+].*
/homeware/bathroom/s2522424/4-tier-pastel-pop-drawers-approx-91cm-x25cm-x-28cm
/homeware/bathroom/towels-and-bathmats
/homeware/bathroom/towels-and-bathmats/s2506420/boutique-luxury-towels
/homeware/bathroom/towels-and-bathmats?page=3&size=36&cols=4&sort=&id=/homeware/bathroom/towels-and-bathmats&priceRange[min]=1&priceRange[max]=14
/homeware/bathroom?page=3&size=36&cols=4&sort=&id=/homeware/bathroom&priceRange[min]=1&priceRange[max]=35
/homeware/bedroom
/homeware/bedroom/bedding-sets
/homeware/bedroom/bedding-sets/s2471012/striped-reversible-printed-duvet-set
/homeware/bedroom/bedding-sets/s2472706/check-printed-reversible-duvet-set
/homeware/bedroom/bedding-sets/s2475332/union-jack-duvet-set
/kids-clothing/boys/shop-by-age/toddler-3mnths-5yrs/s2520246/boys-lollipop-slogan-t-shirt
/kids-clothing/boys/shop-by-age/toddler-3mnths-5yrs/s2520253/boys-2-pack-dinosaur-t-shirts
/kids-clothing/girls/great-value/sale?page=1&size=36&cols=4&sort=price.asc&id=/kids-clothing/girls/great-value/sale&priceRange[min]=0.5&priceRange[max]=7
/kids-clothing/girls/mini-shops/ballet-outfits
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths/s2484120/3-pack-frill-pants-pinks
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths/s2504431/3-pack-l-s-bodysuit
/mens/categories/tops?page=5&size=36&cols=4&sort=&id=/mens/categories/tops&priceRange[min]=2&priceRange[max]=22.5
/mens/categories/trousers-and-chinos
/mens/categories/trousers-and-chinos/s2438566/easy-essential-cuffed-jogging-bottoms
/mens/categories/trousers-and-chinos/s2438574/easy-essential-cuffed-jogging-bottoms
/mens/categories/trousers-and-chinos/s2458939/regatta-zip-off-lightweight-outdoor-trousers
You are on the right track. A negative lookahead will do it:
"^(?!.*\/s\d+)\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/girls|homeware)\/.*"
The ^ anchors to the start of the string. The (?!.*\/s\d+) means that "/sXXXXXXX" can't appear anywhere in the string, and the rest of it matches your required starting tokens.
The reason [^s[0-9]+] didn't work is that [^xyz] matches only one single character. What you're effectively saying there is that you're looking for any character that isn't any combination of "s", "[" and "0-9", followed by "]". e.g. "s[234[s]".
The reason you need to put your negative lookahead at the start of the string is so nothing is matched at all. If you put it after the \/(womens|mens|kids\-clothing\/boys|kids\-clothing\/girls|homeware)\/.*, you would still successfully match everything before the "/sXXXXXXX". i.e. for line 1 of your data, you would match "/homeware/bathroom/".
Yes, you need a negative lookaround:
/^\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/boys|homeware)(?:\/(?:(?!s\d+).)*)+$/gm
If you're comparing one line at a time you don't need the multiline (m) flag. It's probably behaving strangely because you had a character class (denoted by square brakcets) nested inside more square brackets, which doesn't work; you can't nest character classes. This was tested and works on refiddle.