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Extracting a substring before one of two characters using regex

So I have an initial file set:
file1.txt
file2.txt
When I make a change to these files and save them, I append a time stamp to them, so they'd become:
fileN_DD-Mon-YYYY_HHMMSS.txt
But if I was to make any additional saves, the timestamps would begin stacking:
fileN_DD-Mon-YYYY_HHMMSS_DD-Mon-YYYY_HHMMSS.txt
I need a way to get the substring that occurs before the first occurrence of either "." or "_" to get the string that is before them (i.e., actual file name ("fileN")).
I've gotten to this point with
int lastDot = fileName.getName().lastIndexOf('.');
String renamed = fileName.getName().substring(0,lastDot) + getDateTime() + fileName.getName().substring(lastDot);
I've tried using Scanner::useDelimiter to get the first occurrance of a "." or "_" using regexes but no luck.
String renamed = savedFileName(fileName)
public static String savedFileName(String fileName) {
final String TXT = ".txt";
Scanner s = new Scanner(fileName);
s.useDelimiter(<regex>);
String trueFileName = s.next();
s.close();
return trueFileName + getDateTime() + TXT;
for the regex, I've tried "\\W", but that returns just the latest timestamp:
_DD-Mon-YYYY_HHMMSS.txt
, and ".|_" but that returns this monstrosity:
fileN.txt_DD-Mon-YYYY.txt_(more timestamps).txt.

You can use String's split method with regex pattern \.|_:
String longFile = "fileN_DD-Mon-YYYY_HHMMSS.txt";
String shortFile = "file1.txt ";
String pattern = "\\.|_"; // need to escape backslash
System.out.println(longFile.split(pattern)[0]);
System.out.println(shortFile.split(pattern)[0]);
Or, equivalently, regex [._].
Output:
fileN
file1

I am not able to make regex for the following String [duplicate]

I have a string like this:
"core/pages/viewemployee.jsff"
From this code, I need to get "viewemployee". How do I get this using Java?

Suppose that you have that string saved in a variable named myString.
String myString = "core/pages/viewemployee.jsff";
String newString = myString.substring(myString.lastIndexOf("/")+1, myString.indexOf("."));
But you need to make the same control before doing substring in this one, because if there aren't those characters you will get a "-1" from lastIndexOf(), or indexOf(), and it will break your substring invocation.
I suggest looking for the Javadoc documentation.

You can solve this with regex (given you only need a group of word characters between the last "/" and "."):
String str="core/pages/viewemployee.jsff";
str=str.replaceFirst(".*/(\\w+).*","$1");
System.out.println(str); //prints viewemployee

You can split the string first with "/" so that you can have each folder and the file name got separated. For this example, you will have "core", "pages" and "viewemployee.jsff". I assume you need the file name without the extension, so just apply same split action with "." seperator to the last token. You will have filename without extension.
String myStr = "core/pages/viewemployee.bak.jsff";
String[] tokens = myStr.split("/");
String[] fileNameTokens = tokens[tokens.length - 1].split("\\.");
String fileNameStr = "";
for(int i = 0; i < fileNameTokens.length - 1; i++) {
fileNameStr += fileNameTokens[i] + ".";
}
fileNameStr = fileNameStr.substring(0, fileNameStr.length() - 1);
System.out.print(fileNameStr) //--> "viewemployee.bak"

These are file paths. Consider using File.getName(), especially if you already have the File object:
File file = new File("core/pages/viewemployee.jsff");
String name = file.getName(); // --> "viewemployee.jsff"
And to remove the extension:
String res = name.split("\\.[^\\.]*$")[0]; // --> "viewemployee"
With this we can handle strings like "../viewemployee.2.jsff".
The regex matches the last dot, zero or more non-dots, and the end of the string. Then String.split() treats these as a delimiter, and ignores them. The array will always have one element, unless the original string is ..

The below will get you viewemployee.jsff:
int idx = fileName.replaceAll("\\", "/").lastIndexOf("/");
String fileNameWithExtn = idx >= 0 ? fileName.substring(idx + 1) : fileName;
To remove the file Extension and get only viewemployee, similarly:
idx = fileNameWithExtn.lastIndexOf(".");
String filename = idx >= 0 ? fileNameWithExtn.substring(0,idx) : fileNameWithExtn;

Splitting a string at a defined sign - especially "("

I have a little problem with splitting a String
String anl_gewerk = "Text Text Text (KG 412/2)"
String[] parts = anl_gewerk.split("[(]");
anl_gewerk = parts[1];
anl_gewerk = anl_gewerk.replaceAll("\\(","").replaceAll("\\)","");
anl_gewerk = anl_gewerk.replace("KG","");
I have the aforementioned string, and I'm searching for "412/2".
Therefore, I want to split the String into two substrings searching for "(".
Finally I want to grab this String deleting "(", "KG", " " and ")".
When I select anl_gewerk = parts[0]; it works but I get the wrong part, when I change into parts[1] the App crashes.
Please help me

Try to change your code by this:
String anl_gewerk = "Text Text Text (KG 412/2)";
String[] parts = anl_gewerk.split("[(]");
anl_gewerk = parts[1];
String sub[] = anl_gewerk.split(" ");
String test = sub[1];
String result = test.replace(")","");// it gives your result 412/2

regex to match and replace two characters between string

I have a string String a = "(3e4+2e2)sin(30)"; and i want to show it as a = "(3e4+2e2)*sin(30)";
I am not able to write a regular expression for this.

Try this replaceAll:
a = a.replaceAll("\) *(\\w+)", ")*$1");

You can go with this
String func = "sin";// or any function you want like cos.
String a = "(3e4+2e2)sin(30)";
a = a.replaceAll("[)]" + func, ")*siz");
System.out.println(a);

this should work
a = a.replaceAll("\\)(\\s)*([^*+/-])", ") * $2");

String input = "(3e4+2e2)sin(30)".replaceAll("(\\(.+?\\))(.+)", "$1*$2"); //(3e4+2e2)*sin(30)

Assuming the characters within the first parenthesis will always be in similar pattern, you can split this string into two at the position where you would like to insert the character and then form the final string by appending the first half of the string, new character and second half of the string.
string a = "(3e4+2e2)sin(30)";
string[] splitArray1 = Regex.Split(a, #"^\(\w+[+]\w+\)");
string[] splitArray2 = Regex.Split(a, #"\w+\([0-9]+\)$");
string updatedInput = splitArray2[0] + "*" + splitArray1[1];
Console.WriteLine("Input = {0} Output = {1}", a, updatedInput);

I did not try but the following should work
String a = "(3e4+2e2)sin(30)";
a = a.replaceAll("[)](\\w+)", ")*$1");
System.out.println(a);

How to Extract text from given string?

I want to extract a perticular image path string from a given string .
The String is http:\localhost:9090\SpringMVC\images\integration-icon.png
Now i want to get only the path after images like
\images\integration-icon.png
i tried this
Pattern pattern = Pattern.compile("SpringMVC");
Matcher matcher = pattern.matcher(str);
System.out.println("Checking");
if (matcher.find()) {
System.out.println(matcher.group(1));
}
how can i get ?

String filename = filepath.substring(filepath.lastIndexOf("\\") + 1);
or (haven't tried and looks somewhat odd)
String filename = filepath.substring(filepath.lastIndexOf("\\", "images\\".length()) + 1);

String string = "http:\localhost:9090\ZenoBusinessStore\images\integration-icon.png";
int index = string.indexOf("images\\");
String output = string.substring(index);

String text = "http:\localhost:9090\SpringMVC\images\integration-icon.png"
String subText = text.subString(text.indexOf("\images"), text.length());
System.out.println(subText);

String in = "http:\\localhost:9090\\ZenoBusinessStore\\images\\integration-icon.png";
String op = in.replace("http:\\localhost:9090\\ZenoBusinessStore", "");
System.out.println(op);

ZenoBusinessStore must be the name of your project which is constant.
Now split the string
String s = "http:\localhost:9090\ZenoBusinessStore\images\integration-icon.png";
String ary = s.split("ZenoBusinessStore");
Now the 2nd element of the array is your image path.
System.out.println(ary[1]);

Use '\\'. It's because backslash is used in escape sequence like '\n'. With a single \ the compiler have no way to know.