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I am trying to write a boolean function to support double colons :: only for a string. It should reject any string with non-consecutive colon or more than two consecutive colons. The appearance of double colons can be any number. I can write regex which supports double colons but I don't know how to reject so many combinations of non-consecutive and consecutivec colons. Any idea is appreciated!
Valid inputs: Customer::Table, Customer::Table::Sub
Invalid inputs: Customer:Table, Customer::Table:Sub, Customer::::Table
Here is one line option using String#matches:
String input = "Customer::Table::Sub";
if (input.matches("[^:]+(?:::[^:]+)*")) {
System.out.println("MATCH");
}
Demo
Here is an explanation of the regex used:
[^:]+ match one or more non colon characters
(?: start non capturing group
::[^:]+ match :: again followed by one or more non :
)* the group occurring zero or more times
Related
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I'm working on a regex for getting a specific number pattern from the URL string.
Requirements: Desire string should start from - or /, followed by a sequence of digits and ending with a / or nothing.
I tried: [-\/](\d+)(\/|$), but for e.g. in www.abc.com/pages/Toms-1777/14623420046 I want /14623420046(i.e. the second occurring digit sequence), but according to my regex, the result will be -1777/. I was trying negative lookbehind but not able to make any progress. I'm new to all this. Please guide.
Test cases: (with matched pattern)
www.abc.com/pages/Essen-Massage-Therapy-LLC/130561253629638
www.abc.com/biz/finn-mccools-santa-monica-2
www.abc.com/summerset.gardens.7
www.abc.com/pages/Toms-1777/14623420046
www.abc.com/pages/The-Clean-Masters/1403753595526512
www.abc.com/24hfsheepsheadbay
www.abc.com/sample2NVCoolSpace
www.abc.com/pages/Jet-Set-3920/542495615847409
www.abc.com/temp.buildings.77
www.abc.com/2423423453534temp/2312312312312312312
www.abc.com/Ptemp-Gtemp-Dtemp-189398324428792/temp
You want that $ in either case. Instead of 'slash OR end', it's more 'optional slash and then a very much not-optional end'. So.. /?$. You don't need to normally escape slashes, especially in java regexes:
Pattern.compile("[-/](\\d+)/?$")
This reads: From minus or slash, a bunch of digits, then 0 or 1 slashes, then the end. Note, use find() and not matches() - matches only works if the entire string matches, which it won't, as the - or / occurs halfway through.
EDIT: Was missing a backslash in the java string.
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I am confuse in the logic behind the code (?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)")
it is separating numbers and alphabets like input String abc12dc23 then it is spliting it as output abc 12 dc 23.
I just want the explanation how the above code is working?
This regex:
(?<=\D)(?=\d)|(?<=\d)(?=\D)
matches 2 kinds of patterns, as suggested by the | character:
This pattern:
(?<=\D)(?=\d)
and this pattern:
(?<=\d)(?=\D)
The former looks for a position in the string where there is a non-digit (\D) character before that position and a digit (\d) after it. The latter looks for a position where the reverse happens, a digit before and a non-digit after.
To say this in a more abstract way, the regex is looking for digit-non-digit boundaries.
The split method looks for all occurrences of the pattern and splits the string when it finds one.
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This is very basic but can't seem to find a answer when searching.
I have a string that's in the format:
[[[0.093493,51.6037],[0.091015,51.5956],[0.088596,51.5857]]]
The doubles inside the brackets are [latitude coordinate,longitude coordinate].
From this I'd like to extract the coordinates.
What should I put inside the search pattern if I use a Pattern/Matcher solution?
Assume that format with brackets is always correct but the doubles can vary in length.
Basicly what I want the code to do is:
Find "[" left of a number, then find this "," and return what's in between
AND another searchpattern that:
find "," and "]" and return what's inbetween.
Keep it simple by using this regex:
\[(\d+\.\d+),(\d+\.\d+)\]
and repeat the matcher.find() till all matches are found.
You matches are in group #1 and group #2
RegEx Demo
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i have a string like:
String test = "firstName:a,lastName:b,addressOne:line 1,line 2,city:other";
i am trying to do test.replaceAll(",","\",\"").I mean replace , with ",". I want to this only for the whole strings. For eg addressOne is a single string with comma seperated i dont want to replace that. Is there any regex or someother way i can do this?
i should get a string like
"firstName":"a","lastName":"b","addressOne":"line 1 , line 2","city":"other"
after replace , but i am getting
"firstName":"a","lastName":"b","addressOne":"line 1 "," line 2","city":"other".
You can split your string with commas that are followed by a word which has been followed by :. And for this aim you can use a positive look-ahead and for matching the leading word use a negated character class [^:,]+ which will match any string except : and ,:
test.split(",(?=[^:,]+:)")
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I want to use below expression in my program but i don't know what do this regular expression!
please help me.
"(?=(?!^)[,;.:])|(?<=[,;.:])"
in the above expression (?=(?!^)[,;.:]) find any character set that end with [.;,:] or no? what do this (?!^) in this expression?
and this expression find any character set that end with [,;.:] or no?
please help me.
The expression matches 0-length strings that satisfy one of these two conditions:
Ahead of it is one of ,;.:, but not for 0-length strings just before the beginning of the subject string (position 0). So the subject string "." has no match at position 0, only at position 1 because of the following alternative. This is done with positive lookahead (?=) and negative lookahead (?!).
Behind it is one of ,;.:. This is done with positive lookbehind (?<=).
For instance for "aaa,1", you have two matches: at position three (after the last a, because it's followed by ,) and at position 4 (because it's preceded by ,).