I'm using Grails for my web app project. I know the createCriteria method can perform search on existing entries in database. Let's say I have a domain "some_domain" which includes a string variable "domain_string". I want to find out all "domain_strings" that contain either a 7-digit or 10-digit number starting with "1" or "7". (e.g. domain_string1 = ".........1234567.......", domain_string2 = ".......7192839265......", etc)
In my code:
some_domain.createCriteria().list() {
rlike("domain_string", "%/^(1|7){7,10}/%")
}
I've used java regex here and the grails doc tells me that rlike is for regex input. But I can't get the exact output by the code because I'm not familiar with the groovy syntax. Any suggestions for that? Thanks a lot in advance.
You can use
rlike("domain_string", /([^0-9]|^)[17][0-9]{6}([0-9]{3})?([^0-9]|$)/)
See the regex demo.
Details:
([^0-9]|^) - either a non-digit char or start of string
[17] - 1 or 7
[0-9]{6} - any six digits
([0-9]{3})? - an optional occurrence of three digits
([^0-9]|$) - either a non-digit char or end of string.
Groovy regex by java native rules would look like:
def RE = /\D*[17]\d+\D*/
def domain_strings = [ ".........1234567.......", ".......7192839265......", ".......3192839265......", , ".......4192839265......" ]
domain_strings.each{
boolean match = it ==~ RE
println "$it matches? -> $match"
}
prints:
.........1234567....... matches? -> true
.......7192839265...... matches? -> true
.......3192839265...... matches? -> false
.......4192839265...... matches? -> false
You should check your DB SQL dialect if can consume such expressions as-is.
I have the following regular expression that I'm using to remove the dev. part of my URL.
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll(".*\\.(?=.*\\.)", ""));
Outputs: mydomain.com but this is giving me issues when the domains are in the vein of dev.mydomain.com.pe or dev.mydomain.com.uk in those cases I am getting only the .com.pe and .com.uk parts.
Is there a modifier I can use on my regex to make sure it only takes what is before the first . (dot included)?
Desired output:
dev.mydomain.com -> mydomain.com
stage.mydomain.com.pe -> mydomain.com.pe
test.mydomain.com.uk -> mydomain.com.uk
You may use
^[^.]+\.(?=.*\.)
See the regex demo and the regex graph:
Details
^ - start of string
[^.]+ - 1 or more chars other than dots
\. - a dot
(?=.*\.) - followed with any 0 or more chars other than line break chars as many as possible and then a ..
Java usage example:
String result = domain.replaceFirst("^[^.]+\\.(?=.*\\.)", "");
Following regex will work for you. It will find first part (if exists), captures rest of the string as 2nd matching group and replaces the string with 2nd matching group. .*? is non-greedy search that will match until it sees first dot character.
(.*?\.)?(.*\..*)
Regex Demo
sample code:
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "stage.mydomain.com.pe";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "test.mydomain.com.uk";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
output:
mydomain.com
mydomain.com.pe
mydomain.com.uk
mydomain.com
Android 5 and below getting error from my regex pattern on runtime:
java.util.regex.PatternSyntaxException: Syntax error in regexp pattern near index 4:
(?<g1>(http|ftp)(s)?://)?(?<g2>[\w-:#])+(?<TLD>\.[\w\-]+)+(:\d+)?((|\?)([\w\-._~:/?#\[\]#!$&'()*+,;=.%])*)*
Here is code sample:
val urlRegex = "(?<g1>(http|ftp)(s)?://)?(?<g2>[\\w-:#])+(?<TLD>\\.[\\w\\-]+)+(:\\d+)?((|\\?)([\\w\\-._~:/?#\\[\\]#!$&'()*+,;=.%])*)*"
val sampleUrl = "https://www.google.com"
val urlMatchers = Pattern.compile(urlRegex).matcher(sampleUrl)
assert(urlMatchers.find())
This pattern works really fine on all APIs above 21.
It seems the earlier versions do not support named groups. As per this source, the named groups were introduced in Kotlin 1.2. Remove them if you do not need those submatches and only use the regex for validation.
Your regex is very inefficient as it contains a lot of nested quantified groups. See a "cleaner" version of it below.
Also, it seems you want to check if there is a regex match inside your input string. Use Regex#containsMatchIn():
val urlRegex = "(?:(?:http|ftp)s?://)?[\\w:#.-]+\\.[\\w-]+(?::\\d+)?\\??[\\w.~:/?#\\[\\]#!$&'()*+,;=.%-]*"
val sampleUrl = "https://www.google.com"
val urlMatchers = Regex(urlRegex).containsMatchIn(sampleUrl)
println(urlMatchers) // => true
See the Kotlin demo and the regex demo.
If you need to check the whole string match use matches:
Regex(urlRegex).matches(sampleUrl)
See another Kotlin demo.
Note that to define a regex, you need to use the Regex class constructor.
I am new to regex. I would like to retrieve the Hostname from postgreSQL jdbc URL using regex.
Assume the postgreSQL url will be jdbc:postgresql://production:5432/dbname. I need to retrieve "production", which is the hostname. I want to try with regex and not with Java split function. I tried with
Pattern PortFinderPattern = Pattern.compile("[//](.*):*");
final Matcher match = PortFinderPattern.matcher(url);
if (match.find()) {
System.out.println(match.group(1));
}
But it's matching all the string from hostname till the end.
Pattern PortFinderPattern = Pattern.compile(".*:\/\/([^:]+).*");
regex without grouping :
"(?<=//)[^:]*"
[//]([\\w\\d\\-\\.]+)\:
Should be enough to find it reliably. Though this is probably a better regex:
The Hostname Regex
There are some errors in your regex:
[//] - This is only one character, because the [] marks a character class, so it will not fully match //. To match it, you need to write it like this: [/][/] or \/\/.
(.*) - This will match all characters to the end of line. You need to be more specific if you want to go till a certain character. For example you could go to the colon by fetching all characters, which are not colons, like this: ([^:]*).
:* - This makes the colon optional. I guess you forgot to put a dot( every character ) after the colon, like this: :.*.
So here is your regex corrected: \/\/([^:]*):.*.
Hope this helps.
BTW. If the port number is optional after production (:5432), then I suggest the following regex:
\/\/([^/]*)(?::\d+)?\/
To capture also Oracle and MySQL JDBC URL variants with their quirks (e.g. Oracle allowing to use # instead of // or even #//), I use this regexp to get the hostname: [/#]+([^:/#]+)([:/]+|$) Then the hostname is in group 1.
Code e.g.
String jdbcURL = "jdbc:oracle:thin:#//hostname:1521/service.domain.local";
Pattern hostFinderPattern = Pattern.compile("[/#]+([^:/#]+)([:/]+|$)");
final Matcher match = hostFinderPattern.matcher(jdbcURL);
if (match.find()) {
System.out.println(match.group(1));
}
This works for all these URLs (and other variants):
jdbc:oracle:thin:#//hostname:1521/service.domain.local
jdbc:oracle:thin:#hostname:1521/service.domain.local
jdbc:oracle:thin:#hostname/service.domain.local
jdbc:mysql://localhost:3306/sakila?profileSQL=true
jdbc:postgresql://production:5432/dbname
jdbc:postgresql://production/
jdbc:postgresql://production
This assumes that
The hostname is after // or # or a combination thereof (single / would also work, but I don't think JDBC allows that).
After the hostname either : or / or the end of the string follows.
Note that the the + are greedy, this is especially important for the middle one.
Hello all I'm trying to parse out a pretty well formed string into it's component pieces. The string is very JSON like but it's not JSON strictly speaking. They're formed like so:
createdAt=Fri Aug 24 09:48:51 EDT 2012, id=238996293417062401, text='Test Test', source="Region", entities=[foo, bar], user={name=test, locations=[loc1,loc2], locations={comp1, comp2}}
With output just as chunks of text nothing special has to be done at this point.
createdAt=Fri Aug 24 09:48:51 EDT 2012
id=238996293417062401
text='Test Test'
source="Region"
entities=[foo, bar]
user={name=test, locations=[loc1,loc2], locations={comp1, comp2}}
Using the following expression I am able to get most of the fields separated out
,(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))(?=(?:[^']*'[^']*')*(?![^']*'))
Which will split on all the commas not in quotes of any type, but I can't seem to make the leap to where it splits on commas not in brackets or braces as well.
Because you want to handle nested parens/brackets, the "right" way to handle them is to tokenize them separately, and keep track of your nesting level. So instead of a single regex, you really need multiple regexes for your different token types.
This is Python, but converting to Java shouldn't be too hard.
# just comma
sep_re = re.compile(r',')
# open paren or open bracket
inc_re = re.compile(r'[[(]')
# close paren or close bracket
dec_re = re.compile(r'[)\]]')
# string literal
# (I was lazy with the escaping. Add other escape sequences, or find an
# "official" regex to use.)
chunk_re = re.compile(r'''"(?:[^"\\]|\\")*"|'(?:[^'\\]|\\')*[']''')
# This class could've been just a generator function, but I couldn;'t
# find a way to manage the state in the match function that wasn't
# awkward.
class tokenizer:
def __init__(self):
self.pos = 0
def _match(self, regex, s):
m = regex.match(s, self.pos)
if m:
self.pos += len(m.group(0))
self.token = m.group(0)
else:
self.token = ''
return self.token
def tokenize(self, s):
field = '' # the field we're working on
depth = 0 # how many parens/brackets deep we are
while self.pos < len(s):
if not depth and self._match(sep_re, s):
# In Java, change the "yields" to append to a List, and you'll
# have something roughly equivalent (but non-lazy).
yield field
field = ''
else:
if self._match(inc_re, s):
depth += 1
elif self._match(dec_re, s):
depth -= 1
elif self._match(chunk_re, s):
pass
else:
# everything else we just consume one character at a time
self.token = s[self.pos]
self.pos += 1
field += self.token
yield field
Usage:
>>> list(tokenizer().tokenize('foo=(3,(5+7),8),bar="hello,world",baz'))
['foo=(3,(5+7),8)', 'bar="hello,world"', 'baz']
This implementation takes a few shortcuts:
The string escapes are really lazy: it only supports \" in double quoted strings and \' in single-quoted strings. This is easy to fix.
It only keeps track of nesting level. It does not verify that parens are matched up with parens (rather than brackets). If you care about that you can change depth into some sort of stack and push/pop parens/brackets onto it.
Instead of splitting on the comma, you can use the following regular expression to match the chunks that you want.
(?:^| )(.+?)=(\{.+?\}|\[.+?\]|.+?)(?=,|$)
Python:
import re
text = "createdAt=Fri Aug 24 09:48:51 EDT 2012, id=238996293417062401, text='Test Test', source=\"Region\", entities=[foo, bar], user={name=test, locations=[loc1,loc2], locations={comp1, comp2}}"
re.findall(r'(?:^| )(.+?)=(\{.+?\}|\[.+?\]|.+?)(?=,|$)', text)
>> [
('createdAt', 'Fri Aug 24 09:48:51 EDT 2012'),
('id', '238996293417062401'),
('text', "'Test Test'"),
('source', '"Region"'),
('entities', '[foo, bar]'),
('user', '{name=test, locations=[loc1,loc2], locations={comp1, comp2}}')
]
I've set up grouping so it will separate out the "key" and the "value". It will do the same in Java - See it working in Java here:
http://www.regexplanet.com/cookbook/ahJzfnJlZ2V4cGxhbmV0LWhyZHNyDgsSBlJlY2lwZRj0jzQM/index.html
Regular Expression explained:
(?:^| ) Non-capturing group that matches the beginning of a line, or a space
(.+?) Matches the "key" before the...
= equal sign
(\{.+?\}|\[.+?\]|.+?) Matches either a set of {characters}, [characters], or finally just characters
(?=,|$) Look ahead that matches either a , or the end of a line.