Cannot replace strings

Question

I am reading the iptables log output directly from the console and I need to clear the results a little bit.

Currently I am getting:

SRC=192.168.1.1 PROTO=UDP DPT=12638
SRC=192.168.1.1 PROTO=UDP DPT=5636
SRC=192.168.1.1 PROTO=UDP DPT=8861
SRC=192.168.1.1 PROTO=UDP DPT=15114

I am trying to remove SRC= , PROTO= and DPT=...

String results=a.toString();

results.replace("SRC="," ");
results.replace("PROTO="," ");
results.replace("DF TYPE=3"," ");

tv=(TextView)findViewById(R.id.tv1);
tv.setText("results:\n"+results);

And of course nothing is removed :D

You need to reassign the return value of `replace()`. Strings are immutable. — Sotirios Delimanolis, Nov 30 '13 at 04:05

SpringLearner · Answer 1 · 2013-11-30T04:56:17.310

1

use regex this way

results=results.replaceAll("(SRC|PROTO|DF TYPE)=", " ");

This will replace src or proto or df type with a " "(space) in a single line.No need of writing replace 3 times

edited Nov 30 '13 at 04:56

answered Nov 30 '13 at 04:18

SpringLearner

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guness · Answer 2 · 2013-11-30T04:27:59.690

-1

try this way:

results = results.replaceAll("SRC="," ");
results = results.replaceAll("PROTO="," ");

and @Sotirios Delimanolis is right.

edited Nov 30 '13 at 04:27

answered Nov 30 '13 at 04:08

guness

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score -1 · Answer 3 · edited May 23 '17 at 12:12

Change this:

results.replace("SRC="," ");
results.replace("PROTO="," ");
results.replace("DF TYPE=3"," ");

To this:

results = results.replace("SRC="," ");
results = results.replace("PROTO="," ");
results = results.replace("DF TYPE=3"," ");

But you said you wanted to get rid of them, so I would guess that you don't want a blank space, I would guess you want nothing there. You also said "I am trying to remove SRC= , PROTO= and DPT=...", so why do you do this: replace("DF TYPE=3","")? I suggest this:

results = results.replace("SRC=","");
results = results.replace("PROTO=","");
results = results.replace("DPT=","");

Or this (credit to Jason Sperske):

results = results.replaceAll("(SRC|PROTO|DPT)=", " ");

.replace(String, String) will return the replaced String, but will not change the value of the current existing String. As Sotirios Delimanolis said, Strings are immutable.

`.replaceAll()` takes a regex so this would work `results=results.replaceAll("(SRC|PROTO|DF TYPE)=", " ");` — Jason Sperske, Nov 30 '13 at 04:14

Cannot replace strings

3 Answers3