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Matching a string which occurs after a certain pattern

I want to match a string which occurs after a certain pattern but I am not able to come up with a regex to do that (I am using Java).
For example, let's say I have this string,
caa,abb,ksmf,fsksf,fkfs,admkf
and I want my regex to match only those commas which are prefixed by abb. How do I do that? Is it even possible using regexes?
If I use the regex abb, it matches the whole string abb, but I only want to match the comma after that.
I ask this because I wanted to use this regex in a split method which accepts a regex. If I pass abb, as the regex, it will consider the string abb, to be the delimiter and not the , which I want.
Any help would be greatly appreciated.

String test = "caa,abb,ksmf,fsksf,fkfs,admkf";
String regex = "(?<=abb),";
String[] split = test.split(regex);
for(String s : split){
System.out.println(s);
}
Output:
caa,abb
ksmf,fsksf,fkfs,admkf
See here for information:
https://www.regular-expressions.info/lookaround.html

Java regex - How to get spaces and characters?

I am very confused on how Java's regular expressions work. I want to extract two strings from a pattern that looks like this:
String userstatus = "username = not ready";
Matcher matcher = Pattern.compile("(\\.*)=(\\.*)").matcher(userstatus);
System.out.println(matcher.matches());
But printing this will return false. I want to get the username, as well as the space that follows it, and the status string on the right of the equals sign and then store them both separately into two strings.
How would I do this? Thank you!
So the resulting strings should look like this:
String username = "username ";
String status = " not ready";

First, I assume that you are doing this as a learning exercise on regex, because a non-regex solution is easier to implement and to understand.
The problem with your solution is that you are escaping the dot, telling regex engine that you want to match literally a dot '.', not "any character". A simple fix to this problem is to remove \\:
(.*)=(.*)
Demo.
This would work, but it is not ideal. A better approach would be to say "match everything except =, like this:
([^=]*)=(.*)
Demo.

With \\.* you are trying to match zero or many dot characters. So the expression "(\\.*)=(\\.*)" actually expects something like ..=. or ..=. The wild card for any character is a simple .. To fix your code, you can change your regular expression to "(.*)=(.*)". This would match as many characters as it can before the = symbol and all the characters afterwards.
However, this solution is ugly and is not the best approach to do the job. The best thing to do is to use the split method if you want to extract what's on the left and the right side of the = sign.

You can use the split() method of a String.
String[] parts = userstatus.split("=");
String username = parts[0];
String status = parts[1];

- If its a question of fetching 2 String with = as the point of separation, then I think regex will be overkill for it.
- One can use split() method to handle this.
String lhs_Str = userstatus.split("=")[0]
String rhs_Str = userstatus.split("=")[1]

Getting a specific word in a string

I am new to java, i have a string
"rdl_mod_id:0123456789\n\nrdl_mod_name:Driving Test\n\nrdl_mod_type:PUBL\n\nrdl_mod_mode:Practice\n\nrdl_mod_date:2013-04-23"
What I want is to get the Driving Test word. The word is dynamically changes so what I want to happen is get the word between the rdl_mod_name: and the \n.

Try the following.. It will work in your case..
String str = "rdl_mod_id:0123456789\n\nrdl_mod_name:Driving Test\n\nrdl_mod_type:PUBL\n\nrdl_mod_mode:Practice\n\nrdl_mod_date:2013-04-23";
Pattern pattern = Pattern.compile("rdl_mod_name:(.*?)\n");
Matcher matcher = pattern.matcher(str);
while (matcher.find()) {
System.out.println(matcher.group(1));
}
Also you can make use of regex,matcher,pattern to get your desired result..
The following links will also give you a fair idea:
Extract string between two strings in java
Java- Extract part of a string between two special characters
How to get a string between two characters?

I would look into java regular expressions (regex). The String matches method uses a regex to determine if there's a pattern in a string. For what you are doing, I would probably use 'matches(rdl_mod_.*\n)'. The '.*' is a wildcard for strings, so in this context it means anything between rdl_mod and \n. I'm not sure if the matches method can process forward slashes (they signify special text characters), so you might have to replace them with either a different character or remove them altogether.

Use java's substring() function with java indexof() function.

Try this code :
String s = "rdl_mod_id:0123456789\n\nrdl_mod_name:Driving Test\n\nrdl_mod_type:PUBL\n\nrdl_mod_mode:Practice\n\nrdl_mod_date:2013-04-23";
String sArr[] = s.split("\n\n");
String[] sArr1 = sArr[1].split(":");
System.out.println("sArr1[1] : " + sArr1[1]);
The s.split("\n\n");will split the string on basis of \n\n.
The second split i.e. sArr[1].split(":"); will split the second element in array sArr on basis of : i.e split rdl_mod_name:Driving Test into rdl_mod_name and Driving Test.
sArr1[1] is your desired result.

Java Regex to split numbers with unknown number of spaces

I have a string of numbers that are a little weird. The source I'm pulling from has a non-standard formatting and I'm trying to switch from a .split where I need to specify an exact method to split on (2 spaces, 3 spaces, etc.) to a replaceall regex.
My data looks like this:
23574 123451 81239 1234 19274 4312457 1234719
I want to end up with
23574,xxxxx,xxxxx,xxxx
So I can just do a String.split on the ,

I will use \s Regex
This is its usage on Java
String[] numbers = myString.split("\\s+");

final Iterable<String> splitted = Splitter.on('').trimResults().omitEmptyStrings().split(input);
final String output = Joiner.on(',').join(splitted);
with Guava Splitter and Joiner

String pattern = "(\s+)";
Pattern regex = Pattern.compile(pattern);
Matcher match = r.matcher(inputString);
match.replaceAll(",");
String stringToSplit = match.toString();
I think that should do it for you. If not, googling for the Matcher and Pattern classes in the java api will be very helpful.

I understand this problem as a way to obtain integer numbers from a string with blank (not only space) separators.
The accepted solution does not work if the separator is a TAB \t for instance or if it has an \n at the end.
If we define an integer number as a sequence of digits, the best way to solve this is using a simple regular expression. Checking the Java 8 Pattern API, we can find that \D represents any non digit character:
\D A non-digit: [^0-9]
So if the String.split() method accepts a regular expression with the possible separators, it is easy to send "\\D+" to a trimmed string and get the result in one shot like this.
String source = "23574 123451 81239 1234 19274 4312457 1234719";
String trimmed = source.trim();
String[] numbers = trimmed.split("\\D+");
It is translated as split this trimmed string using any non digit character sequence as a possible separator.

String splitting with different character

i think it is a weird question. So here is my splitting:
String s = "asd#asd";
String[] raw1 = s.split("#"); // this has size of two raw[0] = raw[1] = "asd"
However,
String s = "asd$asd";
String[] raw2 = s.split("$"); // this has size of ONE
raw2 is not splitted. Does anyone know why?

Because split() takes a regexp, and $ indicates the end-of-line. If you need to split on a character that is actually a regexp metacharacter, then you'll need to escape it.
See Pattern for the regexp metacharacters.
You may find that StringTokenizer is more appropriate for your needs. This will take a list of characters that you should split on, and it won't interpret them as regular expression metacharacters. However it's a little more verbose and unweildy to use. As Nandkumar notes below, the latest docs states that it is discouraged in new code.

Because split() takes a regex and $ matches the end of a line.
You have to escape it :
s.split("\\$");
See Pattern documentation for more information on regexes.

You have to escape it:
String s = "asd$asd";
String[] raw2 = s.split("\\$"); // this has size of TWO

You need to escape special character, make it
s.split("\\$");