Java Regex Remove Text Between and Including Parenthesis from String

Question

I am programming in Java, and I have a few Strings that look similar to this:

"Avg. Price ($/lb)" 
"Average Price ($/kg)"

I want to remove the ($/lb) and ($/kg) from both Strings and be left with

"Avg. Price" 
"Average Price".

My code checks whether a String str variable matches one of the strings above, and if it does, replaces the text inside including the parentheses with an empty string:

    if(str.matches(".*\\(.+?\\)")){

           str = str.replaceFirst("\\(.+?\\)", "");
    }

When I change str.matches to str.contains("$/lb"); as a test, the wanted substring is removed which leads me to believe there is something wrong with the if statement. Any help as to what I am doing wrong? Thank you.

Update I changed the if statement to:

if(str.contains("(") && str.contains (")"))

Maybe not an elegant solution but it seems to work.

The snippet you've shown works correctly for me. So the problem is somewhere else in your program. Maybe you could post your entire program instead of just two lines? — Dawood ibn Kareem
– Dawood ibn Kareem, Commented Sep 9, 2015 at 4:50
Program works fine for me as well. I ran the following snippet: String str = "Hi ($/lb)"; System.out.println("\"" + str + "\""); if (str.matches(".* \$.+?\$")) { str = str.replaceFirst(" \$.+?\$", ""); } System.out.println("\"" + str + "\""); and got the expected "Hi ($/lb)" "Hi". — Luke
– Luke, Commented Sep 9, 2015 at 4:53
You can use the find() method in java.util.regex.Matcher to find non-exhaustive matches, but you really don't need to. replaceFirst() and replaceAll() handle all the searching as well as the replacing. If they don't find any matches, they return the original string unchanged. — Alan Moore
– Alan Moore, Commented Sep 9, 2015 at 5:36

Dave G · Accepted Answer · 2015-09-09 13:50:31Z

2

str.matches has always been problematic for me. I think it implies a '^' and '$' surrounding the regex you pass it.

Since you just care about replacing any occurrence of the string in question - try the following:

str = str.replaceAll("\\s+\\(\\$\\/(lb|kg)\\)", "");

There is an online regex testing tool that you can also try out to see how your expression works out.

EDIT With regard to your comment, the expression could be altered to just:

str = str.replaceAll("\\s+\\([^)]+\\)$", "");

This would mean, find any section of content starting with one or more white-space characters, followed by a literal '(', then look for any sequence of non-')' characters, followed by a literal ')' at the end of the line.

Is that more in-line with your expectation?

Additionally, heed the comment with regard to 'matches()' vs 'find()' that is very much so what is impacting operation here for you.

edited Sep 9, 2015 at 13:50

answered Sep 9, 2015 at 4:51

Dave G

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2 Comments

pseudorandom Over a year ago

I appreciate the help. The two strings above were just an example. I have different strings other than "Avg. Price ($/lb)" and "Average Price ($/kg)". Too many to list so I don't think your solution will work.

Alan Moore Over a year ago

More precisely, it acts like your regex was really "\\A(?: + yourRegex + ")\\z". For non-exhaustive matches you have to use java.util.regex.Matcher.find().

Bohemian · Accepted Answer · 2015-09-09 13:28:14Z

1

Unlike most other popular application languages, the matches() method in java only returns true if the regex matches the whole string (not part of the string like in perl, ruby, php, javascript etc).

The regex to match bracketed input, including any leading spaces, is:

" *\\(.*?\\)"

and the code to use this to remove matches is:

str = str.replaceAll(" *\\(.+?\\)", "");

Here's some test code:

String str = "foo (stuff) bar(whatever)";
str = str.replaceAll(" *\\(.+?\\)", "");
System.out.println(str);

Output:

"foo bar"

edited Sep 9, 2015 at 13:28

answered Sep 9, 2015 at 13:20

Bohemian♦

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Comments

shan1024 · Accepted Answer · 2015-09-09 04:57:39Z

0

This code is working fine.

    String str = "Avg. Price ($/lb) Average Price ($/kg)";

    if (str.matches(".*\\(.+?\\)")) {
        str = str.replaceFirst("\\(.+?\\)", "");
    }
    System.out.println("str: "+str);

This will print Avg. Price Average Price which is what you need.

Note: I changed replaceFirst with replaceAll here.

answered Sep 9, 2015 at 4:57

shan1024

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james jelo4kul · Accepted Answer · 2015-09-14 22:38:35Z

0

String first = "^(\\w+\\.\\s\\w+)";

This would print out Avg. Price

String second="(\\w\\s\\w)";

This would print out Average Price

hope this simple answer helps

answered Sep 14, 2015 at 22:38

james jelo4kul

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