Easy way of getting List from String by splitting on EOL?

Question

How do I get a List<String> from lines in String? I want to handle CRLF (\r\n) and LF (\n) as EOLs. Empty lines, including those trailing need to be preserved, so that I can use String.join("\n", ...) to get back the original String (however, I don't mind if CRLFs become LFs).

This is what I've come up with:

String x = "\r\n\r\na\nb\r\nc\n\r\n\n";

List<String> lines = Arrays.asList(org.apache.commons.lang3.StringUtils.splitPreserveAllTokens(x.replace("\r", ""), "\n"));

I've seen various other questions but they don't seem to require the preserve empty lines part.

`String.split` takes a regular expression, so you can handle both `CRLR` and `LF` easily. — Brandon, Jun 19 '15 at 12:38

score 3 · Answer 1 · answered Jun 19 '15 at 12:45

3

Use StringReader and Stream:

    String x = "\r\n\r\na\nb\r\nc\n\r\n\n";
    List<String> list = new BufferedReader(new StringReader(x))
        .lines()
        .collect(Collectors.toList());

answered Jun 19 '15 at 12:45

Pshemo · Accepted Answer · 2015-06-19T12:39:47.780

2

You can try with

String[] result = yourString.split("\r?\n", -1);

-1 parameter is limit and it negative value means that trailing empty strings should not be removed from resulting String[] array (I am assuming that converting this array to List<String> is not big problem for you).

edited Jun 19 '15 at 12:39

answered Jun 19 '15 at 12:38

Pshemo

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I don't know how `If n is non-positive then the pattern will be applied as many times as possible and the array can have any length.` translates to it working that way but it works! The example in [String.split(String, int)][https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#split-java.lang.String-int-] even had this! – antak Jun 19 '15 at 12:48

score 1 · Answer 3 · answered Jun 19 '15 at 12:44

If you do not want to go with a regular expression that is needed by String.split, you could use the readLine method of a BufferedReader. An excerpt of its documentation:

Reads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.

Note, that it also splits on "\r" alone.

So you would basically do the following:

String x = ...
BufferedReader reader = new BufferedReader(new StringReader(x));
List<String> lines = new ArrayList<>();
String line;
while ((line = reader.readLine()) != null) {
    lines.add(line);
}

Note, with Java 8 it's easier:

String x = ...
BufferedReader reader = new BufferedReader(new StringReader(x));
List<String> lines = reader.lines().collect(Collectors.toList());

score 0 · Answer 4 · answered Jun 19 '15 at 12:44

0

Try this:

 String[] lines = String.split("\\r\\n?\\n");

 LinkedList<String> list = new LinkedList<String>();

 for(String s : lines) {
     list.add(s);
 }

answered Jun 19 '15 at 12:44

Nico Weisenauer

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Easy way of getting List from String by splitting on EOL?

4 Answers4