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I want to search a string for a specific pattern.
Do the regular expression classes provide the positions (indexes within the string) of the pattern within the string?
There can be more that 1 occurences of the pattern.
Any practical example?
872
\\s*,\\s* It says zero or more occurrence of whitespace characters, followed by a comma and then followed by zero or more occurrence of whitespace characters. These are called short hand expressions. You can find similar regex in this site: http://www.regular-expressions.info/shorthand.html.
Solution: Use the Java Pattern and Matcher classes, supply a regular expression (regex) to the Pattern class, use the find method of the Matcher class to see if there is a match, then use the group method to extract the actual group of characters from the String that matches your regular expression.
Python Regex – Get List of all Numbers from String. To get the list of all numbers in a String, use the regular expression '[0-9]+' with re. findall() method. [0-9] represents a regular expression to match a single digit in the string.
A regular expression is a sequence of characters that forms a search pattern. When you search for data in a text, you can use this search pattern to describe what you are searching for. A regular expression can be a single character, or a more complicated pattern.
Use Matcher:
public static void printMatches(String text, String regex) { Pattern pattern = Pattern.compile(regex); Matcher matcher = pattern.matcher(text); // Check all occurrences while (matcher.find()) { System.out.print("Start index: " + matcher.start()); System.out.print(" End index: " + matcher.end()); System.out.println(" Found: " + matcher.group()); } } special edition answer from Jean Logeart
public static int[] regExIndex(String pattern, String text, Integer fromIndex){ Matcher matcher = Pattern.compile(pattern).matcher(text); if ( ( fromIndex != null && matcher.find(fromIndex) ) || matcher.find()) { return new int[]{matcher.start(), matcher.end()}; } return new int[]{-1, -1}; } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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