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));

Difficulty splitting string at delimiter and keeping it

I have a string that is read in pairs, separated by comma. However, I do not always want to split at the comma because there is not always 1 comma in the input. For example, the string,
(http://www.wolframalpha.com/input/?i=103%2F30+%3D+4a-3b,+71%2F60+%3D+a+%2B+b
,http://www.wolframalpha.com/input/?i=x%5E2%2B5x%2B6,file:///tmp/foo/bar/p,d,f.pdf)
Is read in all one line. For this case, I only want to split at the ,h, and no where else in the string. Essentially, after the split, the strings should be:
http://www.wolframalpha.com/input/?i=103%2F30+%3D+4a-3b,+71%2F60+%3D+a+%2B+b
http://www.wolframalpha.com/input/?i=x%5E2%2B5x%2B6
file:///tmp/foo/bar/p,d,f.pdf
Maintaining the order of the comma in the first string. (I will get rid of parenthesis). I have looked at this stack overflow question, and while helpful, does not correctly split this string. This is in Java. Any help is appreciated.

You can use regex to do the split. Please see below code snippet.
String str = "(http://www.wolframalpha.com/input/?i=103%2F30+%3D+4a-3b,+71%2F60+%3D+a+%2B+b,http://www.wolframalpha.com/input/?i=x%5E2%2B5x%2B6)";
String[] strArr = str.split("(,(?=http))");
You will have Array of all the value which would be possible according to your requirement.

Split on 'http' then re-add it.
Psuedo-code
String input = "http://www.wolframalpha.com/input/?i=103%2F30+%3D+4a-3b,+71%2F60+%3D+a+%2B+b
,http://www.wolframalpha.com/input/?i=x%5E2%2B5x%2B6"
List<String> split = input.split('http');
List<String> finalList = new ArrayList<String>();
for(String fixup in split)
{
finalList.put( "http" + fixup );
}
Final should contain the two URLs.

StringTokenizer delimiters for each Character

I've got a string that I'm supposed to use StringTokenizer on for a course. I've got my plan on how to implement the project, but I cannot find any reference as to how I will make the delimiter each character.
Basically, a String such as "Hippo Campus is a party place" I need to divide into tokens for each character and then compare them to a set of values and swap out a particular one with another. I know how to do everything else, but what the delimiter would be for separating each character?

If you really want to use StringTokenizer you could use like below
String myStr = "Hippo Campus is a party place".replaceAll("", " ");
StringTokenizer tokens = new StringTokenizer(myStr," ");
Or even you can use split for this. And your result will be String array with each character.
String myStr = "Hippo Campus is a party place";
String [] chars = myStr.split("");
for(String str:chars ){
System.out.println(str);
}

Convert the String to an array. There is no delimiter for separating every single character, and it wouldnt make sense to use string tokenizer to do that even if there was.
You can do something like:
char[] individualChars = someString.toCharArray;
Then iterate through that array like so:
for (char c : individualChars){
//do something with the chars.
}

You can do some thing like make the string in to a Char array.
char[] simpleArray = sampleString.toCharArray();
This will split the String to a set of characters. So you can do the operations which you have stated above.

Finding multiple substrings using boundaries in Java

Alright so here is my problem. Basically I have a string with 4 words in it, with each word seperated by a #. What I need to do is use the substring method to extract each word and print it out. I am having trouble figuring out the parameters for it though. I can always get the first one right, but the following ones generally have problems.
Here is the first piece of the code:
word = format.substring( 0 , format.indexOf('#') );
Now from what I understand this basically means start at the beginning of the string, and end right before the #. So using the same logic, I tried to extract the second word like so:
wordTwo = format.substring ( wordlength + 1 , format.indexOf('#') );
//The plus one so I don't start at the #.
But with this I continually get errors saying it doesn't exist. I figured that the compiler was trying to read the first # before the second word, so I rewrote it like so:
wordTwo = format.substring (wordlength + 1, 1 + wordLength + format.indexOf('#') );
And with this it just completely screws it up, either not printing the second word or not stopping in the right place. If I could get any help on the formatting of this, it would be greatly appreciated. Since this is for a class, I am limited to using very basic methods such as indexOf, length, substring etc. so if you could refrain from using anything to complex that would be amazing!

If you have to use substring then you need to use the variant of indexOf that takes a start. This means you can start look for the second # by starting the search after the first one. I.e.
wordTwo = format.substring ( wordlength + 1 , format.indexOf('#', wordlength + 1 ) );
There are however much better ways of splitting a string on a delimiter like this. You can use a StringTokenizer. This is designed for splitting strings like this. Basically:
StringTokenizer tok = new StringTokenizer(format, "#");
String word = tok.nextToken();
String word2 = tok.nextToken();
String word3 = tok.nextToken();
Or you can use the String.split method which is designed for splitting strings. e.g.
String[] parts = String.split("#");
String word = parts[0];
String word2 = parts[1];
String word3 = parts[2];

You can go with split() for this kind of formatting strings.
For instance if you have string like,
String text = "Word1#Word2#Word3#Word4";
You can use delimiter as,
String delimiter = "#";
Then create an string array like,
String[] temp;
For splitting string,
temp = text.split(delimiter);
You can get words like this,
temp[0] = "Word1";
temp[1] = "Word2";
temp[2] = "Word3";
temp[3] = "Word4";

Use split() method to do this with "#" as the delimiter
String s = "hi#vivek#is#good";
String temp = new String();
String[] arr = s.split("#");
for(String x : arr){
temp = temp + x;
}
Or if you want to exact each word... you have it already in arr
arr[0] ---> First Word
arr[1] ---> Second Word
arr[2] ---> Third Word

I suggest that you've a look at the Javadoc for String before you proceed further.
Since this is your homework, I'll give you a couple of hints and maybe you can solve it yourself:
The format for subString is public void subString(int beginIndex, int endIndex). As per the javadoc for this method:
Returns a new string that is a substring of this string. The substring
begins at the specified beginIndex and extends to the character at
index endIndex - 1. Thus the length of the substring is
endIndex-beginIndex.
Note that if you've to use this method, understand that you'll have to shift your beginIndex and endIndex each time because in your situation, you'll have multiple words that are separated by #.
However if you look closely, there's another method in String class that might be helpful to you. That's the public String[] split(String regex) method. The javadoc for this one states:
Splits this string around matches of the given regular expression.
This method works as if by invoking the two-argument split method with
the given expression and a limit argument of zero. Trailing empty
strings are therefore not included in the resulting array.
The split() method looks pretty interesting for your case. You can split your String with the delimiter that you have as the parameter to this method, get the String array and work with that.
Hope this helps you to understand your problem and get started towards a solution :)

Since this is a home work, it may be better to have try to write it your self. But I will give a clue.
Clue:
The indexOf method has another overload: int indexOf(int chr,
int fromIndex) which find the first character chr in the string
from the fromIndex.
http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/String.html
From this clue, the program will look something like this:
Find the index of the first '#' from the start of the string.
Extract the word from 0th character to that index.
Find the index of the first '#' from the character AFTER the first '#'.
Extract the word from the first '#' that index.
... Just do it until you get 4 words or the string ends.
Hope this helps.

I don't know why you're forced to use String#substring, but as others have mentioned, it seems like the wrong method for the kind of functionality you need.
String#split(String regex) is what you would use for such a problem, or, if your input sequence is something you don't control, I would suggest you look at the overloaded method String#split(String regex, int limit); this way you can impose a limit on the amount of matches you make, controlling your resulting array.

Splitting strings based on a delimiter

I am trying to break apart a very simple collection of strings that come in the forms of
0|0
10|15
30|55
etc etc. Essentially numbers that are seperated by pipes.
When I use java's string split function with .split("|"). I get somewhat unpredictable results. white space in the first slot, sometimes the number itself isn't where I thought it should be.
Can anybody please help and give me advice on how I can use a reg exp to keep ONLY the integers?
I was asked to give the code trying to do the actual split. So allow me to do that in hopes to clarify further my problem :)
String temp = "0|0";
String splitString = temp.split("|");
results
\n
0
|
0
I am trying to get
0
0
only. Forever grateful for any help ahead of time :)

I still suggest to use split(), it skips null tokens by default. you want to get rid of non numeric characters in the string and only keep pipes and numbers, then you can easily use split() to get what you want. or you can pass multiple delimiters to split (in form of regex) and this should work:
String[] splited = yourString.split("[\\|\\s]+");
and the regex:
import java.util.regex.*;
Pattern pattern = Pattern.compile("\\d+(?=([\\|\\s\\r\\n]))");
Matcher matcher = pattern.matcher(yourString);
while (matcher.find()) {
System.out.println(matcher.group());
}

The pipe symbol is special in a regexp (it marks alternatives), you need to escape it. Depending on the java version you are using this could well explain your unpredictable results.
class t {
public static void main(String[]_)
{
String temp = "0|0";
String[] splitString = temp.split("\\|");
for (int i=0; i<splitString.length; i++)
System.out.println("splitString["+i+"] is " + splitString[i]);
}
}
outputs
splitString[0] is 0
splitString[1] is 0
Note that one backslash is the regexp escape character, but because a backslash is also the escape character in java source you need two of them to push the backslash into the regexp.

You can do replace white space for pipes and split it.
String test = "0|0 10|15 30|55";
test = test.replace(" ", "|");
String[] result = test.split("|");
Hope this helps for you..

You can use StringTokenizer.
String test = "0|0";
StringTokenizer st = new StringTokenizer(test);
int firstNumber = Integer.parseInt(st.nextToken()); //will parse out the first number
int secondNumber = Integer.parseInt(st.nextToken()); //will parse out the second number
Of course you can always nest this inside of a while loop if you have multiple strings.
Also, you need to import java.util.* for this to work.

The pipe ('|') is a special character in regular expressions. It needs to be "escaped" with a '\' character if you want to use it as a regular character, unfortunately '\' is a special character in Java so you need to do a kind of double escape maneuver e.g.
String temp = "0|0";
String[] splitStrings = temp.split("\\|");

The Guava library has a nice class Splitter which is a much more convenient alternative to String.split(). The advantages are that you can choose to split the string on specific characters (like '|'), or on specific strings, or with regexps, and you can choose what to do with the resulting parts (trim them, throw ayway empty parts etc.).
For example you can call
Iterable<String> parts = Spliter.on('|').trimResults().omitEmptyStrings().split("0|0")

This should work for you:
([0-9]+)

Considering a scenario where in we have read a line from csv or xls file in the form of string and need to separate the columns in array of string depending on delimiters.
Below is the code snippet to achieve this problem..
{ ...
....
String line = new BufferedReader(new FileReader("your file"));
String[] splittedString = StringSplitToArray(stringLine,"\"");
...
....
}
public static String[] StringSplitToArray(String stringToSplit, String delimiter)
{
StringBuffer token = new StringBuffer();
Vector tokens = new Vector();
char[] chars = stringToSplit.toCharArray();
for (int i=0; i 0) {
tokens.addElement(token.toString());
token.setLength(0);
i++;
}
} else {
token.append(chars[i]);
}
}
if (token.length() > 0) {
tokens.addElement(token.toString());
}
// convert the vector into an array
String[] preparedArray = new String[tokens.size()];
for (int i=0; i < preparedArray.length; i++) {
preparedArray[i] = (String)tokens.elementAt(i);
}
return preparedArray;
}
Above code snippet contains method call to StringSplitToArray where in the method converts the stringline into string array splitting the line depending on the delimiter specified or passed to the method. Delimiter can be comma separator(,) or double code(").
For more on this, follow this link : http://scrapillars.blogspot.in