extract specific word from comma separated string in java using regex

Question

input - [1, 1111, 2020, BMW, Frontier, EXTENDED CAB PICKUP 2-DR, Silver, 16558] I want to extract here BMW and I am using (^(?:[^\\,]*\\,){3}) this regex. This results into - BMW, Frontier, EXTENDED CAB PICKUP 2-DR, Silver, 16558] . Could any one help me with this? thanks in advance

Answer 1

If it is comma seperated string, you could just split function from the string class which would convert the comma seperated string to array. Refer - Link

The string split() method breaks a given string around matches of the given regular expression.

Syntax - Public String [ ] split ( String regex, int limit )

Input String: 016-78967
Regular Expression: -
Output : {"016", "78967"}

Then you could into the array to find out the particular keyword from it.

Answer 2

As you can only enter a pattern without making use of groups, you could make use of finite repetition for example {0,1000} in the positive lookbehind as Java does not support infinite repetition.

(?<=^\\[[^,]{0,1000},[^,]{0,1000},[^,]{0,1000},\\h{0,10})\\w{3,10}(?=[^\\]\\[]*\\])

Explanation

• (?<= Positive lookbehind, assert what is on the left is
  • ^\[ Start of string, match [
  • [^,]{0,1000},[^,]{0,1000},[^,]{0,1000}, Match 3 times any char except , followed by the ,
  • \h{0,10} Match 0-10 times a horizontal whitespace char
• ) Close lookbehind
• \w{3,10} Match 3-10 word chars
• (?= Positive lookahead, assert what is on the right is
  • [^\]\[]*\] Match until the ]
• ) Close lookahead

Java demo

Code example

final String regex = "(?<=^\\[[^,]{0,1000},[^,]{0,1000},[^,]{0,1000},\\h{0,10})\\w{3,10}(?=[^\\]\\[]*\\])";
final String string = "[1, 1111, 2020, BMW, Frontier, EXTENDED CAB PICKUP 2-DR, Silver, 16558]";

final Pattern pattern = Pattern.compile(regex);
final Matcher matcher = pattern.matcher(string);

while (matcher.find()) {
    System.out.println(matcher.group(0));
}

Output

BMW