如何使用replaceAll删除部分文本

Question

There is a String text System.out.println(text); looks like this

So the traveller sat down by the side of that old man,
face to face with the serene sunset; 
and all his friends came softly back and stood around him. 

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Another String subText

System.out.println(subText); is simply a part of the above string and looks like this

So the traveller sat down by the side of that old man,
face to face with the serene sunset;

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I need to get rid of this subText part text = text.replaceAll(subtext, ""); but this does not do anything with the text?

Answer 1

In this particular case it does not matter, but you really should use replace instead of replaceAll :

text = text.replace(subtext, "");

The replaceAll method uses regular expressions, and some characters have special meaning.

In this particular case you won't see any difference because there must be something subtly different in subtext , so it cannot be found in text . Perhaps there's extra white space or the line break character is encoded differently. It's very hard to see differences in white space looking at output produced by System.out.println .

Answer 2

The reason it's not working is because 'replaceAll()` expects the search term to be a regular expression .

You should use replace() , which use searches for plain text and incidentally still replaces all occurrences, instead:

text = text.replace(subtext, "");

As to why it didn't work with replaceAll() , who knows. To diagnose, you could see if in fact it's in your text as follows:

System.out.println(text.contains(subtext));