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How to take input in expected form in java?

I want to take a string input in
%d+%d
format in java.How do i do it?
I know that I can do this with string.split() method. But I feel that it is going to be way more complex if I had to deal with more strings in input. Like
%d+%d-%d
I am looking for solutions that are close to a scanf solution for c.
I tried this for %d+%d
Scanner scanner = new Scanner(System.in);
String str = scanner.next();
String first,second;
String[] arr = str.split("\\+");
first = arr[0];
second = arr[1];
scanner.close();
And this for %d+%d-%d+%d..........=%d-%d+%d.....+%d...
private final String[] splitLoL(String txt) {
LinkedList<String> strList1 = new LinkedList<String>();
LinkedList<String> strList2 = new LinkedList<String>();
LinkedList<String> strList3 = new LinkedList<String>();;
strList1.addAll(Arrays.asList(txt.split("\\+")));
for(String str : strList1) {
String[] proxy = str.split("-");
strList2.addAll(Arrays.asList(proxy));
}
for(String str : strList2) {
String[] proxy = str.split("=");
strList3.addAll(Arrays.asList(proxy));
}
String[] strArr = new String[strList3.size()];
for(int i = 0; i < strArr.length; i++) {
strArr[i] = new String(strList3.get(i));
}
return strArr;
}

Try this:
String str = scanner.nextLine();
List<String> str2 = new ArrayList();
Matcher m = Pattern.compile("\\d+").matcher(str);
while(m.find()) {
str2.add(m.group());
}

Or you can do the following using JDK 9+:
import java.util.Scanner;
public class ScannerTrial {
public static void main(String[] args) {
Scanner scanner = new Scanner(" 4 z zz ggg 22 e");
scanner.findAll("\\d+").forEach((e) -> System.out.println(e.group()));
}
}
This would print
4 22

Java .split() out of bounds

I have a problem with my code.
I'm trying to extract the name of the channels from a .txt file.
I can't understand why the method line.split() give me back an array with 0 length:
Someone can help me?
This is the file .txt:
------------[channels.txt]---------------------
...
#CH id="" tvg-name="Example1" tvg-logo="http...
#CH id="" tvg-name="Example2" tvg-logo="http...
#CH id="" tvg-name="Example3" tvg-logo="http...
#CH id="" tvg-name="Example4" tvg-logo="http...
...
This is my code:
try {
FileInputStream VOD = new FileInputStream("channels.txt");
BufferedReader buffer_r = new BufferedReader(new InputStreamReader(VOD));
String line;
ArrayList<String> name_channels = new ArrayList<String>();
while ((line = buffer_r.readLine()) != null ) {
if (line.startsWith("#")) {
String[] first_scan = line.split(" tvg-name=\" ", 2);
String first = first_scan[1]; // <--- out of bounds
String[] second_scan = first.split(" \"tvg-logo= ", 2);
String second = second_scan[0];
name_channels.add(second);
} else {
//...
}
}
for (int i = 0; i < name_channels.size(); i++) {
System.out.println("Channel: " + name_channels.get(i));
}
} catch(Exception e) {
System.out.println(e);
}

So you have examples like this
#CH id="" tvg-name="Example1" tvg-logo="http...
And are trying to split on these strings
" tvg-name=\" "
" \"tvg-logo= "
Neither of those strings are in the example. There's a spurious space appended, and the space at the start of the second is in the wrong place.
Fix the strings and here's a concise but complete program to demonstrate
interface Split {
static void main(String[] args) {
String line = "#CH id=\"\" tvg-name=\"Example1\" tvg-logo=\"http...";
String[] first_scan = line.split(" tvg-name=\"", 2);
String first = first_scan[1]; // <--- out of bounds
String[] second_scan = first.split("\" tvg-logo=", 2);
String second = second_scan[0];
System.err.println(second);
}
}
Of course, if you have any lines that start with '#' but don't match, you'll have a similar problem.
This sort of thing is probably done better with regexs and capturing groups.

There is a whitespace after the last double quote in tvg-name=\" which does not match the data in your example.
When you use split with line.split(" tvg-name=\"", 2) then the first item in the returned array will be #CH id="" and the second part will be Example1" tvg-logo="http..."
If you want to get the value of tvg-name= you might use a regex with a capturing group where you would capture not a double quote using a negated character class [^"]+
tvg-name="([^"]+)"
try {
FileInputStream VOD = new FileInputStream("channels.txt");
BufferedReader buffer_r = new BufferedReader(new InputStreamReader(VOD));
String line;
ArrayList<String> name_channels = new ArrayList<String>();
while((line = buffer_r.readLine()) != null ){
if(line.startsWith("#")){
String regex = "tvg-name=\"([^\"]+)\"";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(line);
while (matcher.find()) {
name_channels.add(matcher.group(1));
}
} else {
// ...
}
}
for(int i = 0; i < name_channels.size(); i++){
System.out.println("Channel: " + name_channels.get(i));
}
}catch(Exception e){
System.out.println(e);
}

How to convert a string contains array format to java array or list?

I have a string like this:
String res = '["A","B","0","1"]';
How to convert it to an array or list in Java to become like this:
String[] r = {"A","B","0","1"};

Since your string is a correct Json string, you may use the gson library:
String s = "[\"A\",\"B\",\"0\",\"1\"]";
Gson gson = new GsonBuilder().create();
String[] arr = gson.fromJson(s, String[].class);
// {"A","B","0","1"}

Without using Gson, You can get the desired result by following below approach -
String inputStr = "[\"A\",\"B\",\"0\",\"1\"]";
String[] strArray = inputStr.split("[^\\w\\d]");
List<String> list = new ArrayList<>();
for (String str : strArray) {
if (str != null && !str.isEmpty()) {
list.add(str);
}
}
System.out.println(list);
Output will be: [A, B, 0, 1]

String res = "[A,B,0,1]";
res = res.replace("[", "");
res = res.replace("]", "");
res = res.replaceAll(",", "");
String [] arrayOutput = new String [res.length()];
char [] ar = res.toCharArray();
for(int i = 0; i< ar.length; i++)
{
char buffer = ar[i];
arrayOutput[i] = String.valueOf(buffer);
}

Parse hashtags between symbols

I need to parse hashtags from String (test comment #georgios#gsabanti sefse #afa).
String text = "test comment #georgios#gsabanti sefse #afa";
String[] words = text.split(" ");
List<String> tags = new ArrayList<String>();
for ( final String word : words) {
if (word.substring(0, 1).equals("#")) {
tags.add(word);
}
}
In the end i need an Array with "#georgios" , "#gsabanti" , "#afa" elements.
But now #georgios#gsabanti showing like one hashtag.
How to fix it?

+1 for the Regular Expressions:
Matcher matcher = Pattern.compile("(#[^#\\s]*)")
.matcher("test comment #georgios#gsabanti sefse #afa");
List<String> tags = new ArrayList<>();
while (matcher.find()) {
tags.add(matcher.group());
}
System.out.println(tags);

Here is a simple way of doing that
String text = "test comment #georgios#gsabanti sefse #afa";
String patternst = "#[a-zA-Z0-9]*";
Pattern pattern = Pattern.compile(patternst);
Matcher matcher = pattern.matcher(text);
List<String> tags = new ArrayList<String>();
while (matcher.find()) {
tags.add(matcher.group(0));
}
I hope it will work for you :)

Use Arraylist instead of array:
String text = "test comment #georgios#gsabanti sefse #afa";
ArrayList<String> hashTags = new ArrayList()<>;
char[] c = text.toCharArray();
for(int i=0;i<c.length;i++) {
if(c[i]=='#') {
String hash = "";
for(int j=i+1;j<c.length;j++) {
if(c[j]==' ' || c[j]=='#') {
hashTags.add(hash);
hash="";
break;
}
hash+=c[j];
}
}
}

String text = "test comment #georgios#gsabanti sefse #afa";
String[] words = text.split("(?=#)|\\s+")
List<String> tags = new ArrayList<String>();
for ( final String word : words) {
if (!word.isEmpty() && word.startsWith("#")) {
tags.add(word);
}
}

You can split your string at " " or "#" and keep the delimiters and filter those out which start with "#" like below:
public static void main(String[] args){
String text = "test comment #georgios#gsabanti sefse #afa";
String[] tags = Stream.of(text.split("(?=#)|(?= )")).filter(e->e.startsWith("#")).toArray(String[]::new);
System.out.println(Arrays.toString(tags));
}

String reverse using Java'sstringbuilder

I develop using Java to make a little project.
I want String reverse.
If I entered "I am a girl", Printed reversing...
Already I tried to use StringBuilder.
Also I write it using StringBuffer grammar...
But I failed...
It is not printed my wish...
WISH
My with Print -> "I ma a lrig"
"I am a girl" -> "I ma a lrig" REVERSE!!
How can I do?..
Please help me thank you~!!!
public String reverse() {
String[] words = str.split("\\s");
StringTokenizer stringTokenizer = new StringTokenizer(str, " ");
for (String string : words) {
System.out.print(string);
}
String a = Arrays.toString(words);
StringBuilder builder = new StringBuilder(a);
System.out.println(words[0]);
for (String st : words){
System.out.print(st);
}
return "";
}

Java 8 code to do this :
public static void main(String[] args) {
String str = "I am a girl";
StringBuilder sb = new StringBuilder();
// split() returns an array of Strings, for each string, append it to a StringBuilder by adding a space.
Arrays.asList(str.split("\\s+")).stream().forEach(s -> {
sb.append(new StringBuilder(s).reverse() + " ");
});
String reversed = sb.toString().trim(); // remove trailing space
System.out.println(reversed);
}
O/P :
I ma a lrig

if you do not want to go with lambda then you can try this solution too
String str = "I am a girl";
String finalString = "";
String s[] = str.split(" ");
for (String st : s) {
finalString += new StringBuilder(st).reverse().append(" ").toString();
}
System.out.println(finalString.trim());
}