CODEWITHSUNDEEP
javastring
Raghavan
Raghavan

Reputation: 401

Replace white spaces only in part of the string

I have a String like 

"This is apple tree"

I want to remove the white spaces available until the word apple.After the change it will be like

"Thisisapple tree"

I need to achieve this in single replace command combined with regular expressions.

Upvotes: 0

Views: 87

Answers (4)

Grayman
Grayman

Reputation: 629

If you want to use a regular expression you could try:

Matcher matcher = Pattern.compile("^(.*?\\bapple\\b)(.*)$").matcher("This is an apple but this apple is an orange");
System.out.println((!matcher.matches()) ? "No match" : matcher.group(1).replaceAll(" ", "") + matcher.group(2));

This checks that "apple" is an individual word and not just part of another word such as "snapple". It also splits at the first use of "apple".

Upvotes: 0

Pshemo
Pshemo

Reputation: 124215

For now it looks like you may be looking for 

String s = "This is apple tree";
System.out.println(s.replaceAll("\\G(\\S+)(?<!(?<!\\S)apple)\\s", "$1"));

Output: Thisisapple tree.

Explanation:

  • \G represents either end of previous match or start of input (^) if there was no previous match yet (when we are attempting to find first match)
  • \S+ represents one or more non-whitespace characters (to match words, including non-alphabetic characters like ' or punctuation)
  • (?<!(?<!\\S)apple)\\s negative-look-behind will prevent accepting whitespace which has apple before it (I added another negative-look-behind before apple to make sure that it doesn't have any non-whitespace which ensures that this is not part of some other word)
  • $1 in replacement represents match from group 1 (the one from (\S+)) which represents word. So we are replacing word and spaces with only word (effectively removing spaces)

WARNING: This solution assumes that

  • sentence doesn't start with space,
  • words can be separated with only one space.

If we want to get rid of this assumptions we would need something like:

System.out.println(s.replaceAll("^\\s+|\\G(\\S+)(?<!(?<!\\S)apple)\\s+", "$1"));
  • ^\s+ will allow us to match spaces at beginning of string (and replace them with content of group 1 (word) which in this case will be empty, so we will simply remove these whitespaces)
  • \s+ at the end allows us to match word and one or more spaces after it (to remove them)

Upvotes: 1

spirit
spirit

Reputation: 3415

This is achived via lookahead assertion, like this:

    String str = "This is an apple tree";
    System.out.println(str.replaceAll(" (?=.*apple)", ""));

It means: replace all spaces in front of which there anywhere word apple

Upvotes: 0

Ankit Khettry
Ankit Khettry

Reputation: 1027

A single replace() is unlikely to solve your problem. You could do something like this..

String s[] = "This is an apple tree, not an orange tree".split("apple");
System.out.println(new StringBuilder(s[0].replace(" ","")).append("apple").append(s[1]));

Upvotes: 0

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