We Keep Coding

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

How can i split String in java with custom pattern

I am trying to get the location data from this string using String.split("[,\\:]");
String location = "$,lat:27.980194,lng:46.090199,speed:0.48,fix:1,sats:6,";
String[] str = location.split("[,\\:]");
How can i get the data like this.
str[0] = 27.980194
str[1] = 46.090199
str[2] = 0.48
str[3] = 1
str[4] = 6
Thank you for any help!

If you just want to keep the numbers (including dot separator), you can use:
String[] str = location.split("[^\\d\\.]+");
You will need to ignore the first element in the array which is an empty string.
That will only work if the data names don't contain numbers or dots.

String location = "$,lat:27.980194,lng:46.090199,speed:0.48,fix:1,sats:6,";
Matcher m = Pattern.compile( "\\d+\\.*\\d*" ).matcher(location);
List<String> allMatches = new ArrayList<>();
while (m.find( )) {
allMatches.add(m.group());
}
System.out.println(allMatches);

Quick and Dirty:
String location = "$,lat:27.980194,lng:46.090199,speed:0.48,fix:1,sats:6,";
List<String> strList = (List) Arrays.asList( location.split("[,\\:]"));
String[] str = new String[5];
int count=0;
for(String s : strList){
try {
Double d =Double.parseDouble(s);
str[count] = d.toString();
System.out.println("In String Array:"+str[count]);
count++;
} catch (NumberFormatException e) {
System.out.println("s:"+s);
}
}

Reverse a string as per length of first word

I am new to Java Strings.
Actually I have the code to reverse words:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test2 {
public static void main(String[] args) throws IOException
{
System.out.println("enter a sentence");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String rev =br.readLine();
String [] bread = rev.split(" ");
for(int z =bread.length-1;z>=0;z--)
{
System.out.println(bread[z]);
}
}
}
For the above code I get:
Input :Bangalore is a city
Output: City is a Bangalore
But I want the output to be like below:
Input: Bangalore is a city
Output:cityaisba ng a lore
Another Example:
Input: Hello Iam New To Java.Java is object Oriented language.
Output: langu age Ori en tedo bjec ti sjava. javaToNe wIamolleH
Please help me out

Here is one way you could do it:
String rev = br.readLine();
String [] bread = rev.split(" ");
int revCounter = 0;
for(int z = bread.length - 1; z >= 0; z--)
{
String word = bread[z];
for(int i = 0; i < word.length(); i++)
{
// If char at current position in 'rev' was a space then
// just print space. Otherwise, print char from current word.
if(rev.charAt(revCounter) == ' ')
{
System.out.print(' ');
i--;
}
else
System.out.print(word.charAt(i));
revCounter++;
}
}

When I run your code I get following result:
city
a
is
Bangalore
So to have it in a single line, why don't you add a space and print a single line?
System.out.println("enter a sentence");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String rev = br.readLine();
String[] bread = rev.split(" ");
for (int z = bread.length - 1; z >= 0; z--) {
System.out.print(bread[z] + " ");
}

I didn't check the validity of your code like GHajba did. But if you want spaces to remain on specific places it might be an option to remove all spaces and put them back according to their index in the original String.
Remove all
newBread = newBread.replace(" ", "");
Put them back
StringBuilder str = new StringBuilder(newBread);
for (int index = oldBread.indexOf(" ") ;
index >= 0 ;
index = oldBread.indexOf(" ", index + 1))
{
str.insert(index, ' ');
}
newBread = str.toString();
I came up with this quick and there might be better ways to do this, maybe without StringBuilder, but this might help you until you find a better way.

Try with this (i've used a string as input):
String original = "Bangalore is a city";
System.out.println("Original : "+original);
StringBuilder inverted = new StringBuilder();
StringBuilder output = new StringBuilder();
String temp = "";
String[] split = original.split("\\s+");
for (int i = split.length - 1; i >= 0; i--) {
inverted.append(split[i]);
}
temp = inverted.toString();
for (String string : split) {
int currLenght = string.length();
String substring = temp.substring(0,currLenght);
temp = temp.replaceAll(substring, "");
output.append(substring).append(" ");
}
System.out.println("Converted : "+output.toString());

Append the reversed words without the spaces into a StringBuffer.
StringBuffer b = new StringBuffer();
for (int i = bread.length-1; i >= 0 ; i--) {
b.append(bread[i]);
}
Then insert the spaces of the original String into the StringBuffer.
int spaceIndex, prevIndex = 0;
while ((spaceIndex = rev.indexOf(" ", prevIndex + 1)) != -1) {
b.insert(spaceIndex, ' ');
prevIndex = spaceIndex;
}

store 1d array from text file java

Am I reading the following input correctly?
Here is my code so far:
while ((line = br.readLine()) != null) {
line = line.substring(line.indexOf('[')+1, line.indexOf(']'));
String[] parts = line.split(",");
for (int i = 0; i< parts.length; i++) {
rangeNo[i]= Integer.parseInt(parts[i]);
System.out.println("{" + rangeNo[i] + "}");
}
}
and this is my input
[2,9], [3,11]
Also, when I try to print the value of rangeNo[3] it return 0 instead of 3
can someone help me out with this?

Do you expect [2,9], [3,11] to be in one line or two separate lines?
If its supposed to be one line then you might want to try something like this
Integer rangeNo[] = new Integer[10];
String line = "[2,9], [3,11]";
line = line.replace('[', ' ');
line = line.replace(']', ' ');
String[] parts = line.split(",");
for (int i = 0; i < parts.length; i++) {
rangeNo[i] = Integer.parseInt(parts[i].trim());
System.out.println("{" + rangeNo[i] + "}");
}

when you check here
line = line.substring(line.indexOf('[')+1, line.indexOf(']'));
it's matching first condition. i.e works fine for [2,9] not after that thus only 2 and 9 are getting stored here.
String[] parts = line.split(",");
so
parts[0]=2
parts[1]=9
parts[2]=0

Java String to String[] of possible prefixes

I would like to create an array of prefixes to iterate through from a string.
This is to create some tests where the options are matched using String.startsWith
For example "start" would become { "s", "st", "sta", "star", "start" }

You can try below code,
String str = "start";
String strArray[] = new String [str.length()];
for (int i=0 ; i< str.length() ; i++)
{
strArray[i] = str.substring(0,i+1);
System.out.println("strArray["+i+"] = " +strArray[i] );
}
Output:
strArray[0] = s
strArray[1] = st
strArray[2] = sta
strArray[3] = star
strArray[4] = start