replace unknown number of values in a java strings

Question

How do i replace multiple words with an empty string "" in a string with java. I tried with for loop to replace those in single quotes by adding then in an array like below, but it replaces one word per printout.

String str = "this house 'is' really 'big' and 'attractive'.";
String[] values={"is","big","attractive"};
for(String s: values){
    String replaced = str.replace(s, "");
    System.out.println( replaced );
}

I'm getting this output:

> this house ' ' really 'big' and 'attractive'.
> this house 'is' really ' ' and 'attractive'.
> this house 'is' really 'big' and ' '.

What I need is this:

> this house ' ' really ' ' and ' '.

Remius answer is correct, but if you want to make your code working replace "String replaced" with "str" (and thereby improve the result at every iteration) and move the println behind the for loop. — ospf
– ospf, Commented Mar 15, 2018 at 12:35

Reimeus · Accepted Answer · 2018-03-15 12:25:29Z

6

System.out.println(str.replaceAll("is|big|attractive", ""));

answered Mar 15, 2018 at 12:25

Reimeus

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1 Comment

AxelH Over a year ago

String.join("|", values) could help to get the regex from the array.

gargkshitiz · Accepted Answer · 2018-03-16 07:40:59Z

1

Why your approach is wrong

Strings in Java are immutable - when you call replace , it doesn't change the contents of the existing string - it returns a new string with the modifications. So you want:

str= str.replace(s, ""); instead of String replaced = str.replace(s, "");

Also, write this code after the for loop: System.out.println(str); and omit System.out.println( replaced ); as its placement is inside the for loop right now resulting into multiple statements getting printed.

Note that after doing all this, code would print th house '' really '' and ''. and NOT the desired output.

Why follow Reimeus's answer OR use a generic regex expression

Even after correcting your code, you would NOT get the desired results, hence :)

edited Mar 16, 2018 at 7:40

answered Mar 15, 2018 at 12:32

gargkshitiz

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Comments

Stultuske · Accepted Answer · 2018-03-15 12:25:53Z

1

You re-start each iteration from the original String, which you don't modify.

You could change the String your str refers to and use that, like this:

      for(String s: values){
             str = str.replace(s, "");
             System.out.println( str );
       }

answered Mar 15, 2018 at 12:25

Stultuske

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Comments

Arjun Kay · Accepted Answer · 2018-03-15 12:33:58Z

0

You are re-initializingreplaced in every iteration. So you end up with a string in which only the last element of array values is replaced. To get the desired output, try this:

String replaced =  str;
for(String s: values){
    replaced = replaced.replace(s, "");
}

edited Mar 15, 2018 at 12:33

answered Mar 15, 2018 at 12:30

Arjun Kay

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7 Comments

Stultuske Over a year ago

This answer makes no sense at all. String replaced = s; will cause a Compilation error

Arjun Kay Over a year ago

Rookie mistake. Corrected! :)

Stultuske Over a year ago

so why do you need the 'replaced' variable at all? just replacing replaced by str would do the trick ;)

Arjun Kay Over a year ago

OP used a seperate variable for output. So I did the same. (This is my first ever answer on SO. Lot to learn :D )

Arjun Kay Over a year ago

But even this approach won't produce the desired output.

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