Develop Reference

Java - String splitting

I read a txt with data in the following format: Name Address Hobbies
Example(Bob Smith ABC Street Swimming)
and Assigned it into String z
Then I used z.split to separate each field using " " as the delimiter(space) but it separated Bob Smith into two different strings while it should be as one field, same with the address. Is there a method I can use to get it in the particular format I want?
P.S Apologies if I explained it vaguely, English isn't my first language.
String z;
try {
BufferedReader br = new BufferedReader(new FileReader("desc.txt"));
z = br.readLine();
} catch(IOException io) {
io.printStackTrace();
}
String[] temp = z.split(" ");

If the format of name and address parts is fixed to consist of two parts, you could just join them:
String z = ""; // z must be initialized
// use try-with-resources to ensure the reader is closed properly
try (BufferedReader br = new BufferedReader(new FileReader("desc.txt"))) {
z = br.readLine();
} catch(IOException io) {
io.printStackTrace();
}
String[] temp = z.split(" ");
String name = String.join(" ", temp[0], temp[1]);
String address = String.join(" ", temp[2], temp[3]);
String hobby = temp[4];
Another option could be to create a format string as a regular expression and use it to parse the input line using named groups (?<group_name>capturing text):
// use named groups to define parts of the line
Pattern format = Pattern.compile("(?<name>\\w+\\s\\w+)\\s(?<address>\\w+\\s\\w+)\\s(?<hobby>\\w+)");
Matcher match = format.matcher(z);
if (match.matches()) {
String name = match.group("name");
String address = match.group("address");
String hobby = match.group("hobby");
System.out.printf("Input line matched: name=%s address=%s hobby=%s%n", name, address, hobby);
} else {
System.out.println("Input line not matching: " + z);
}

I can think of three solutions.
In order from best to worst:
Different delimiter
Enforce the format to always have two names, two address parts and one hobby
Have a dictionary with names and hobbies, check each word to determine which type it is and then group them together as needed.
(The 3rd option is not meant as a serious alternative.)

As others have mentioned, using spaces as both field delimiter and inside fields is problematic. You could use a regex pattern to split the line (paste (\w+ \w+) (\w+ \w+) (.+) in Regex101 for an explanation):
Pattern pattern = Pattern.compile("(\\w+ \\w+) (\\w+ \\w+) (.+)");
Matcher matcher = pattern.matcher("Bob Smith ABC Street Bowling Fishing Rollerblading");
System.out.println("matcher.matches() = " + matcher.matches());
for (int i = 0; i <= matcher.groupCount(); i++) {
System.out.println("matcher.group(" + i + ") = " + matcher.group(i));
}
This would give the following output:
matcher.matches() = true
matcher.group(0) = Bob Smith ABC Street Bowling Fishing Rollerblading
matcher.group(1) = Bob Smith
matcher.group(2) = ABC Street
matcher.group(3) = Bowling Fishing Rollerblading
However this only works for this exact format. If you get a line with three name parts for example:
John B Smith ABC Street Swimming
This will get split into John B as the name, Smith ABC as the address and Street Swimming as hobbies.
So either make 100% sure your input will always match this format or use a different delimiter.

The split() method majorly works on the 2 things:
Delimiter and
The String Object
Sometimes on limit too.
Whatever limit you will provide, the split() method will do its work according to that.
It doesn't understand whether the left substring is a name or not, same as for the right substring.
Have a look at this code snippet:
String assets = "Gold:Stocks:Fixed Income:Commodity:Interest Rates";
String[] splits = assets.split(":");
System.out.println("splits.size: " + splits.length);
for(String asset: splits){
System.out.println(assets);
}
OutPut
splits.size: 5
Gold
Stocks
Fixed Income // with space
Commodity
Interest Rates // with space
The output came with spaces because I provided the ; as a delimiter.
This probably helped you to get your answer.
Find Detailed Information on Split():
Top 5 Use cases of Split()
Java Docs : Split()

It depends on the data you're dealing with. Will the name always consist of a first and last name? Then you can simply combine the first two elements from the resulting array into a new string.
Otherwise, you might have to find a different way to separate out the different pieces within the txt file. Possibly a comma? Some character that you know won't ever be used in your normal data.

Assuming that every line follows the format
Bob Smith ABC Street Swimming
ie, name surname.... this code can manually manipulate the data for you:
String[] temp = z.split(" ");
String[] temp2 = new String[temp.length - 1];
temp2[0] = temp[0] + " " + temp[1];
for (int i = 2; i < temp.length; i++) {
temp2[i] = temp2[i];
}
temp = temp2;

java: splitting one array into two separate arrays based on even and odd positions of the array

I'm new to Java and I'm having difficulties I have an assignment that requires me to load a text file with the name of a state followed by its capital onto the program and read the state names into one array and the capital names into another array. The way I tackled this was that I loaded the text file into one array called total and made a count. I wanted to split those with an even position to be in a separate array called capital and those in an odd position to be in an array called states. But I'm not sure how exactly to put that into code. This is what I have so far
Sample of Text File:
Alabama
Montgomery
Alaska
Juneau
Arizona
Phoenix
Arkansas
Little Rock
California
Sacramento
Colorado
Denver
Connecticut
Hartford
Delaware
Dover
Florida
Tallahassee
Georgia
Atlanta
Hawaii
Honolulu
And my code so far
public class StateCapitals
{
/**
* #param args the command line arguments
* #throws java.io.FileNotFoundException
*/
public static void main(String[] args) throws FileNotFoundException
{
File inputfile;
File outputfile;
inputfile = new File("capitals.txt");
outputfile = new File ("InOrder.txt");
String stateandcity;
int count;
count = 1;
PrintWriter pw;
Scanner kb;
kb = new Scanner(inputfile);
String [] total;
total = new String[100];
String [] capitals;
capitals = new String[50];
String [] states;
states = new String [50];
while (kb.hasNextLine())
{
stateandcity = kb.nextLine();
System.out.println("Count: " +count + " " + stateandcity);
total[count-1] = stateandcity;
count ++;
}
if (count % 2 == 0)
states = new String [50]; //where i need help
}}

The algorithm will be like this:
Read everything into total like you have already thought of.
Use a for loop to loop from i=0 to i=100 (or however many items there are to be split), incrementing by 2 each time.
Assign total[i] to capital[i / 2].
Assign total[i + 1] to states[i / 2].
It is as simple as that! Try doing it yourself first. If you are having difficulties, just leave a comment!

I would separate them while reading them like this. (Save yourself a loop)
while (kb.hasNextLine())
{
state[count] = kb.nextLine();
capitals[count] = kb.nextLine();
System.out.println("Count: " +count + " " +
state[count] + "," +
capitals[count]);
count ++;
}

Java Regex : How to search a text or a phrase in a large text

I have a large text file and I need to search a word or a phrase in the file line by line and output the line with the text found in it.
For example, the sample text is
And the earth was without form,
Where [art] thou?
if the user search for thou word, the only line to be display is
Where [art] thou?
and if the user search for the earth, the first line should be displayed.
I tried using the contains function but it will display also the without when searching only for thou.
This is my sample code :
String[] verseList = TextIO.readFile("pentateuch.txt");
Scanner kbd = new Scanner(System.in);
int counter = 0;
for (int i = 0; i < verseList.length; i++) {
String[] data = verseList[i].split("\t");
String[] info3 = data[3].split(" ");
System.out.print("Search for: ");
String txtSearch = kbd.nextLine();
LinkedList<String> searchedList = new LinkedList<String>();
for (String bible : verseList){
if (bible.contains(txtSearch)){
searchedList.add(bible);
counter++;
}
}
if (searchedList.size() > 0){
for (String s : searchedList){
String[] searchedData = s.split("\t");
System.out.printf("%s - %s - %s - %s \n",searchedData[0], searchedData[1], searchedData[2], searchedData[3]);
}
}
System.out.print("Total: " + counter);
So I am thinking of using regex but I don't know how.
Can anyone help? Thank you.

Since sometimes variables have non-word characters at boundary positions, you cannot rely on \b word boundary.
In such cases, it is safer to use look-arounds (?<!\w) and (?!\w), i.e. in Java, something like:
"(?<!\\w)" + searchedData[n] + "(?!\\w)"

To match a String that contains a word, use this code:
String txtSearch; // eg "thou"
if (str.matches(".*?\\b" + txtSearch + "\\b.*"))
// it matches
This code builds a regex that only matches if both ends of txtSearch fall and the start/end of a word in the string by using \b, which means "word boundary".

Checking whether the String contains multiple words

I am getting the names as String. How can I display in the following format: If it's single word, I need to display the first character alone. If it's two words, I need to display the first two characters of the word.
John : J
Peter: P
Mathew Rails : MR
Sergy Bein : SB
I cannot use an enum as I am not sure that the list would return the same values all the time. Though they said, it's never going to change.
String name = myString.split('');
topTitle = name[0].subString(0,1);
subTitle = name[1].subString(0,1);
String finalName = topTitle + finalName;
The above code fine, but its not working. I am not getting any exception either.

There are few mistakes in your attempted code.
String#split takes a String as regex.
Return value of String#split is an array of String.
so it should be:
String[] name = myString.split(" ");
or
String[] name = myString.split("\\s+);
You also need to check for # of elements in array first like this to avoid exception:
String topTitle, subTitle;
if (name.length == 2) {
topTitle = name[0].subString(0,1);
subTitle = name[1].subString(0,1);
}
else
topTitle = name.subString(0,1);

The String.split method split a string into an array of strings, based on your regular expression.
This should work:
String[] names = myString.split("\\s+");
String topTitle = names[0].subString(0,1);
String subTitle = names[1].subString(0,1);
String finalName = topTitle + finalName;

First: "name" should be an array.
String[] names = myString.split(" ");
Second: You should use an if function and the length variable to determine the length of a variable.
String initial = "";
if(names.length > 1){
initial = names[0].subString(0,1) + names[1].subString(0,1);
}else{
initial = names[0].subString(0,1);
}
Alternatively you could use a for loop
String initial = "";
for(int i = 0; i < names.length; i++){
initial += names[i].subString(0,1);
}

You were close..
String[] name = myString.split(" ");
String finalName = name[0].charAt(0)+""+(name.length==1?"":name[1].charAt(0));
(name.length==1?"":name[1].charAt(0)) is a ternary operator which would return empty string if length of name array is 1 else it would return 1st character

This will work for you
public static void getString(String str) throws IOException {
String[] strr=str.split(" ");
StringBuilder sb=new StringBuilder();
for(int i=0;i<strr.length;i++){
sb.append(strr[i].charAt(0));
}
System.out.println(sb);
}

Java Scanner Class useDelimiter Method

I have to read from a text file containing all the NCAA Division 1 championship games since 1933,
the file is in this format: 1939:Villanova:42:Brown:30
1945:New York University:70:Ohio State:65 **The fact that some Universities have multiple white spaces is giving me lots of trouble beause we are only to read the school names and discard the year, points and colon. I do not know if I have to use a delimiter that discards what spaces, but buttom line is I am a very lost.
We are to discard the date, points, and ":". I am slightly fimilar with the useDelimiter method but, I have read that a .split("") might be useful. I am having a great deal of problems due to my lack of knowledge in patterns.
THIS IS WHAT I HAVE SO FAR:
class NCAATeamTester
{
public static void main(String[]args)throws IOException
{
NCAATeamList myList = new NCAATeamList(); //ArrayList containing teams
Scanner in = new Scanner(new File("ncaa2012.data"));
in.useDelimiter("[A-Za-z]+"); //String Delimeter excluding non alphabetic chars or ints
while(in.hasNextLine()){
String line = in.nextLine();
String name = in.next(line);
String losingTeam = in.next(line);
//Creating team object with winning team
NCAATeamStats win = new NCAATeamStats(name);
myList.addToList(win); //Adds to List
//Creating team object with losing team
NCAATeamStats lose = new NCAATeamStats(losingTeam);
myList.addToList(lose)
}
}
}

What about
String[] spl = line.split(':');
String name1 = spl[1];
String name2 = spl[3];
?
Or, if there are more records at the same line, use regular expressions :
String line = "1939:Villanova:42:Brown:30 1945:New York University:70:Ohio State:65";
Pattern p = Pattern.compile("(.*?:){4}[0-9]+");
Matcher m = p.matcher(line);
while (m.find())
{
String[] spl = m.group().split(':');
String name = spl[1];
String name2 = spl[3];
}