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javaregexend-of-line

java regex $ metacharacter

I am new to java regex.I saw this in Docs:

$ The end of a line

But when I try this snippet:

String str = "firstline\r\nsecondline";
String regex = "$";
System.out.println(str.replaceAll(regex, "*"));

I guess result will be:

firstline*
secondline*

But I see this result:

firstline
secondline*

It seems that it $ only matches the end of a String. So why do the docs say it matches "The end of a line"?

Solution

  • You must enable multiline mode, then $ will match both, the end of a line and the end of the input:

    http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html#MULTILINE

    i.e.:

    Pattern.compile("$",Pattern.MULTILINE);

    You can also use the flag expression (?m), i.e.:

    Pattern.compile("(?m)$");

    The oracle docs you cite are really quite imprecise here. The documentation of the pattern class (link above) is more precise and should be your reference for Java RegExs.