Develop Reference

Deleting content of every string after first empty space

How can I delete everything after first empty space in a string which user selects? I was reading this how to remove some words from a string in java. Can this help me in my case?

You can use replaceAll with a regex \s.* which match every thing after space:
String str = "Hello java word!";
str = str.replaceAll("\\s.*", "");
output
Hello
regex demo
Like #Coffeehouse Coder mention in comment, This solution will replace every thing if the input start with space, so if you want to avoid this case, you can trim your input using string.trim() so it can remove the spaces in start and in end.

Assuming that there is no space in the beginning of the string.
Follow these steps-
Split the string at space. It will create an array.
Get the first element of that array.
Hope this helps.
str = "Example string"
String[] _arr = str.split("\\s");
String word = _arr[0];
You need to consider multiple white spaces and space in the beginning before considering the above code.
I am not native to JAVA Programming but have an idea that it has split function for string.
And the reference you cited in the question is bit complex, while you can achieve the desired thing very easily.
P.S. In future if you make a mind to get two words or three, splitting method is better (assuming you have already dealt with multiple white-spaces) else substring is better.

A simple way to do it can be:
System.out.println("Hello world!".split(" ")[0]);

// Taking 'str' as your string
// To remove the first space(s) of the string,
str = str.trim();
int index = str.indexOf(" ");
String word = str.substring(0, index);
This is just one method of many.
str = str.replaceAll("\\s+", " "); // This replaces one or more spaces with one space
String[] words = str.split("\\s");
String first = words[0];

The simplest solution in my opinion would be to just locate the index which the user wants it to be cut off at and then call the substring() method from 0 to the index they wanted. Set that = to a new string and you have the string they want.
If you want to replace the string then just set the original string = to the result of the substring() method.
Link to substring() method: https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#substring(int,%20int)

There are already 5 perfectly good answers, so let me add a sixth one. Variety is the spice of life!
private static final Pattern FIRST_WORD = Pattern.compile("\\S+");
public static String firstWord(CharSequence text) {
Matcher m = FIRST_WORD.matcher(text);
return m.find() ? m.group() : "";
}
Advantages over the .split(...)[0]-type answers:
It directly does exactly what is being asked, i.e. "Find the first sequence of non-space characters." So the self-documentation is more explicit.
It is more efficient when called on multiple strings (e.g. for batch processing a large list of strings) because the regular expression is compiled only once.
It is more space-efficient because it avoids unnecessarily creating a whole array with references to each word when we only need the first.
It works without having to trim the string.
(I know this is probably too late to be of any use to the OP but I'm leaving it here as an alternative solution for future readers.)

This would be more efficient
String str = "Hello world!";
int spaceInd = str.indexOf(' ');
if(spaceInd != -1) {
str = str.substring(0, spaceInd);
}
System.out.println(String.format("[%s]", str));

Confused regarding split in Java

I am trying to take a text from a file, and take the a's and b's out using split function.
String inStr = in.readLine();
// for example "a1a1a1a1b"
String lettersStr = letters.readLine();
// for example "ab"
Then i'm doing this trying to split all the letters i want.
Why is this not working?
String outFinal = "\"\\\\s*["+ lettersStr +"]\\\\s*\"";
String[] inSplit = inStr.split(outFinal);
What i'm trying to accomplish is
inStr.split("\\s*[ab]\\s*"));
Which works fine but the problem is that since i'm using a BufferedReader (fileread) the letters to cut out keep changing, hence why i can't just use the line above.
Thanks in advance
Regards

Change
String outFinal = "\"\\\\s*["+ lettersStr +"]\\\\s*\"";
to
String outFinal = "\\s*["+ lettersStr +"]\\s*";

The filter string - removing some chars

is there a function in Java which removed from a string unwanted chars given by me? If not, what the most effective way to do it. I would like realize it in JAVA
EDIT:
But, I want reach for example:
String toRescue="#8*"
String text = "ra#dada882da(*%"
and after call function:
string text2="#88*"

You can use a regular expression, for example:
String text = "ra#dada882da(*%";
String text2 = text.replaceAll("[^#8*]", "");
After executing the above snippet, text2 will contain the string "#88*".

The Java String has many methods which can help you, such as
String.replace(char old, char new);
String.split(regex);
String.substring(int beginIndex);
These and many others are described in the javadoc : http://docs.oracle.com/javase/6/docs/api/java/lang/String.html

Split a String In Java against the split rule?

I have a string like this:
String str="\"myValue\".\"Folder\".\"FolderCentury\"";
Is it possible to split the above string by . but instead of getting three resulting strings only two like:
columnArray[0]= "myValue"."Folder";
columnArray[1]= "FolderCentury";
Or do I have to use an other java method to get it done?

Try this.
String s = "myValue.Folder.FolderCentury";
String[] a = s.split(java.util.regex.Pattern.quote("."));
Hi programmer/Yannish,
First of all the split(".") will not work and this will not return any result. I think java String split method not work for . delimiter, so please try java.util.regex.Pattern.quote(".") instead of split(".")

As I posted on the original Post (here), the next code:
String input = "myValue.Folder.FolderCentury";
String regex = "(?!(.+\\.))\\.";
String[] result=input.split(regex);
System.out.println("result: "+Arrays.toString(result));
Produces the required output (an array with two values):
result: [myValue.Folder, FolderCentury]

If the problem you're trying to solve is really that specific, you could do it even without using regular expression matches at all:
int lastDot = str.lastIndexOf(".");
columnArray[0] = str.substring(0, lastDot);
columnArray[1] = str.substring(lastDot + 1);

How to replace || (two pipes) from a string with | (one) pipe

I am getting response for some images in json format within this tag:
"xmlImageIds":"57948916||57948917||57948918||57948919||57948920||57948921||57948‌ ​922||57948923||57948924||57948925||57948926||5794892"
What i want to do is to separate each image id using .split("||") of the string class. Then append url with this image id and display it.
I have tried .replace("\"|\"|","\"|"); but its not working for me. Please help.
EDIT: Shabbir, I tried to update your question according to your comments below. Please edit it again, if I didn't get it right.

Use
.replace("||", "|");
| is no special char.
However, if you are using split() or replaceAll instead of replace(), beware that you need to escape the pipe symbol as \\|, because these methods take a regex as parameter.
For example:
public static void main(String[] args) {
String in = "\"xmlImageIds\":\"57948916||57948917||57948918||57948919||57948920||57948921||57948‌922||57948923||57948924||57948925||57948926||5794892\"".replace("||", "|");
String[] q = in.split("\"");
String[] ids = q[3].split("\\|");
for (String id : ids) {
System.out.println("http://test/" + id);
}
}

I think I know what your problem is. You need to assign the result of replace(), not just call it.
String s = "foo||bar||baz";
s = s.replace("||", "|");
System.out.println(s);
I tested it, and just calling s.replace("||", "|"); doesn't seem to modify the string; you have to assign that result back to s.
Edit: The Java 6 spec says "Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar." (the emphasis is mine).

According to http://docs.oracle.com/javase/6/docs/api/java/lang/String.html, replace() takes chars instead of Strings. Perhaps you should try replaceAll(String, String) instead? Either that, or try changing your String ("") quotation marks into char ('') quotation marks.
Edit: I just noticed the overload for replace() that takes a CharSequence. I'd still give replaceAll() a try though.

String pipe="pipes||";
System.out.println("Old Pipe:::"+pipe);
System.out.println("Updated Pipe:::"+pipe.replace("||", "|"));

i dont remember how it works that method... but you can make your own:
String withTwoPipes = "helloTwo||pipes";
for(int i=0; i<withTwoPipes.lenght;i++){
char a = withTwoPipes.charAt(i);
if(a=='|' && i<withTwoPipes.lenght+1){
char b = withTwoPipes.charAt(i+1);
if(b=='|' && i<withTwoPipes.lenght){
withTwoPipes.charAt(i)='';
withTwoPipes.charAt(i+1)='|';
}
}
}
I think that some code like this should work... its not a perfect answer but can help...