This is my piece of code I want to split the string with $ symbol but the string doesn't getting spitted.
Here is my code:
String str="first$third$nine%seventh";
String s[]=str.split("$");
System.out.println(s[0]);
The output is the whole string:
first$third$nine%seventh
split takes a regular expression as an argument. $ is a magic character in regex.
If you escape it with backslashes, it will be used as a normal character instead of a special regex character.
String s[]=str.split("\\$");
This is a very common thing in string class. Ans this has been already asked and answers are available in stackoverflow.
You should escape the regular expression symbol in split method. There are so many characters like $,?,*,^,+ which should be escaped while using as a parameter in split method.
Related
I am a beginner in Java. I don't understand how the below code is able to print all the characters in a string:-
System.out.println(yourString.replaceAll(".", "$0\n"));
I have tried reading the documentation on replaceAll and regex, still no clue.
"." is a regular expression which matches any single character. $0 in the replacement string is a placeholder for the full match of the regex. \n is a line break.
Summarized, this snippet replaces each character with itself and adds a line break after the character.
The syntax for replaceAll() method is as follows:
replaceAll(String regex, Stringreplacement) where:
regex : regular expression
replacement : replacement sequence of characters
so when you what to replace a character with \n basically every character will be printed in a different line. For example: yourString = "Hello." =>
output: Hello with every character on a different line
If the String (as you specified) is String yourString = "-"; so the result of System.out.println(yourString.replaceAll(".", "$0\n")); will be "-\n".
Actually, if you need to print all of the String characters why are you using replaceAll? Coz System.out.println(yourString); will do it perfectly.
This question already has answers here:
Groovy/Java split string on parentheses "("
(5 answers)
What special characters must be escaped in regular expressions?
(13 answers)
Closed 3 years ago.
I am trying to split a java string with the character "(".
For example :
split("wer(sde")= "wer"+"sde".
But it give exception. Is there a way to split this string using split() function without changing the character "(" to some other character.
String[] cp=cmd.split("{");
Output:
Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition
The thing is, split() receives as parameter a regular expression. Both {} and () are meta-characters and have a special meaning in a regex, so you need to escape them like this:
String[] cp = cmd.split("\\(|\\)");
The method split of String accept a String, that parameter is a regex :
public String[] split(String regex)
Splits this string around matches of the given regular expression.
Since ( is a reserved character in regex, you need to escape it \(.
But in Java, you need to escape twice \\(, once for the String and the second for the regex
This gives :
s.split("\\(");
Parentheses mean something in RegEx, they're used to group characters together. As such, if you intend to reference the literal character, '(' you must escape it within the RegEx:
String[] cp = cmd.split("\\(");
Note the use of two backslashes. This is because the JVM will also interpret a backslash as a metacharacter for escape purposes, so you must escape the backslash itself with another backslash in order for it to make it into the RegEx.
I am trying break a String in various pieces using delimiter(":").
String sepIds[]=ids.split(":");
It is working fine. But when I replace ":" with " * " and use " * " as delimiter, it doesn't work.
String sepIds[]=ids.split("*"); //doesn't work
It just hangs up there, and doesn't execute further.
What mistake I am making here?
String#split takes a regular expression as parameter. In regex some chars have special meanings so they need to be escaped, for example:
"foo*bar".split("\\*")
the result will be as you expect:
[foo, bar]
You could also use the method Pattern#quote to simplify the task.
"foo*bar".split(Pattern.quote("*"))
String.split expects a regular expression argument. * has got a meaning in regex. So if you want to use them then you need to escape them like this:
String sepIds[]=ids.split("\\*");
The argument of .split() is a regular expression, not a string literal. Therefore you need to escape * since it is a special regex character. Write:
ids.split("\\*");
This is how you would split agaisnt one or more spaces:
ids.split("\\s+");
Note that Guava has Splitter which is very, very fast and can split against literals:
Splitter.on('*').split(ids);
'*' and '.' are special characters you have to blackshlash it.
String sepIds[]=ids.split("\\*");
To read more about java patterns please visit that page.
That is expected behaviour. The documentation for the String split function says that the input string is treated as a regular expression (with a link explaining how that works). As Germann points out, '*' is a special character in regular expressions.
Java's String.split() uses regular expressions to split up the string (unlike similar functions in C# or python). * is a special character in regular expressions and you need to escape it with a \ (backslash). So you should use instead:
String sepIds[]=ids.split("\\*");
You can find more information on regular expressions anywhere on the internet a quite complete list of special characters supported by java should be here: http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html
I want to split function in java.But it s not working good.
String mystring = "ersin#$gulbahar#$ev";
String [] scripts= mystring.split("#$"); //it does not split.
how can i fix this?
String mystring = "ersin#$gulbahar#$ev";
String[] scripts = mystring.split("#\\$");
System.out.println(Arrays.toString(scripts));
OUTPUT:
[ersin, gulbahar, ev]
try this:
mystring.split("#\\$")
the split method uses a Regex to split the text, a $ character has other mean in a regex
split takes a regular expression as a parameter, and $ is a special character in a regular expression meaning "match the end of the string".
Since you want to match a literal $, not the end of the string, you need to escape it with a backslash: mystring.split("#\\$"); should work.
Escape $ in your expression: split() takes a regular expression as parameter! Common issue...
split this String using function split. Here is my code:
String data= "data^data";
String[] spli = data.split("^");
When I try to do that in spli contain only one string. It seems like java dont see "^" in splitting. Do anyone know how can I split this string by letter "^"?
EDIT
SOLVED :P
This is because String.split takes a regular expression, not a literal string. You have to escape the ^ as it has a different meaning in regex (anchor at the start of a string). So the split would actually be done before the first character, giving you the complete string back unaltered.
You escape a regular expression metacharacter with \, which has to be \\ in Java strings, so
data.split("\\^")
should work.
You need to escape it because it takes reg-ex
\\^
Special characters like ^ need to be escaped with \
This does not work because .split() expects its argument to be a regex. "^" has a special meaing in regex and so does not work as you expect. To get it to work, you need to escape it. Use \\^.
The reason is that split's parameter is a regular expression, so "^" means the beginning of a line. So you need to escape to ASCII-^: use the parameter "\\^".