Java: Remove String from StringBuilder

Question

I want to remove String from StringBuilder

Example

String aaa = "sample";
String bbb = "sample2";
String ccc = "sample3";

In another part

StringBuilder ddd = new StringBuilder();
ddd.append(aaa);
ddd.append(bbb);
ddd.append(ccc);

I want to check if StringBuilder ddd contains String aaa and remove it

if (ddd.toString().contains(aaa)) {
    //Remove String aaa from StringBuilder ddd
}

Is that possible? Or is there any other way to do like that?

Take a look at [this question](http://stackoverflow.com/a/12353395/3227787). — Bruno Toffolo, Jan 28 '14 at 14:32
Why add it in the first place? I'm assuming this is a very contrived sample: why can't you add a check to whatever condition it is before adding `aaa`? — Jeroen Vannevel, Jan 28 '14 at 14:33
@JeroenVannevel. Not necessarily contrived. A StringBuilder can be created from a pre-existing string or other source. Removing bits of it may not be the best way to handle things, as you point out, but it may be the only alternative in some cases. — Mad Physicist, Jan 28 '14 at 14:41

Evgeniy Dorofeev · Accepted Answer · 2014-01-28T14:49:09.200

12

try this

    int i = ddd.indexOf(aaa);
    if (i != -1) {
        ddd.delete(i, i + aaa.length());
    }

edited Jan 28 '14 at 14:49

answered Jan 28 '14 at 14:37

Evgeniy Dorofeev

133,369
30
199
275

1

You need to do `i + aaa.length()` for the second argument, as [`StringBuilder#delete`](http://docs.oracle.com/javase/7/docs/api/java/lang/StringBuilder.html#delete%28int,%20int%29) takes an `end` index, not a length. – ajp15243 Jan 28 '14 at 14:40

score 5 · Answer 2 · answered Jan 28 '14 at 14:38

5

try this

public void delete(StringBuilder sb, String s) {
    int start = sb.indexOf(s);
    if(start < 0)
        return;

    sb.delete(start, start + s.length());
}

answered Jan 28 '14 at 14:38

grexter89

1,091
10
23

score 2 · Answer 3 · answered Jan 28 '14 at 18:02

2

Create a string from ddd and use replace().

ddd.toString().replace(aaa,"");

answered Jan 28 '14 at 18:02

Fco P.

2,486
17
20

score 0 · Answer 4 · answered Jan 28 '14 at 14:36

0

It can be done by :

ddd.delete(from, to);

answered Jan 28 '14 at 14:36

Salah

8,567
3
26
43

And, for performance, use `indexOf` instead of `toString().contains` – Chris Jan 28 '14 at 14:37

Java: Remove String from StringBuilder

4 Answers4

Linked