We Keep Coding

I need to take all the lines at once and work with them, but I get line-by-line reception

when there is a reading of lines and work with them continues line by line
I need to accept multi-line input first and only then to work the code
public class OrderRestaurant {
public static void main(String[] args) throws IOException {
InputStreamReader reader = new InputStreamReader(System.in, StandardCharsets.UTF_8);
BufferedReader in = new BufferedReader(reader);
String line = null;
TreeMap<String, LinkedList<Integer>> orderMap = new TreeMap<String, LinkedList<Integer>>();
Set<Integer> tableSet = new TreeSet<Integer>();
while ((line = in.readLine()) != null) {
String[] orders = line.split(",");
for (int i = 0; i < orders.length; i++) {
tableSet.add(Integer.parseInt(orders[1]));
}
if (!(orderMap.containsKey(orders[2]))) {
LinkedList<Integer> numbersTables = new LinkedList<>();
numbersTables.add(Integer.parseInt(orders[1]));
orderMap.put(orders[2], numbersTables);
} else {
orderMap.get(orders[2]).addLast(Integer.parseInt(orders[1]));
}
StringBuilder sBuilder = new StringBuilder("Table");
Set<String>keysOrderMapSet=orderMap.keySet();
for (String keyString : keysOrderMapSet) {
sBuilder.append(',').append(keyString);
}
for(Integer key : tableSet){
sBuilder.append("\n").append(key);
for(Map.Entry<String, LinkedList<Integer>> entry : orderMap.entrySet())
{
LinkedList<Integer> numbersOrder = entry.getValue();
int counterOrder = 0;
for (int i = 0; i < numbersOrder.size(); i++) {
if(numbersOrder.get(i)==key) {
counterOrder++;
}
}
sBuilder.append(',').append(counterOrder);
}
}
System.out.println(sBuilder.toString());
}
}
}
all input is green, further you can see that the output after the program runs is formed in parts and only at the end is displayed in its entirety.

What I understand from the question is that you want to read all lines from the console first then need to do any operation or work and after that, you want to print the result for each line on the console. If that is the case then you need to create an intermediate array or list to hold the data of each line. Please refer below steps:
Create an empty list as readLineByLineString that holds your input line by line.
Read line from the console using Scanner or BufferedReader.
Add that line to the list by readLineByLineString.add(line);
Read all the lines and add to the list until all test cases satisfy or required conditions.
Now you have all your data line by line in an intermediate list i.e. readLineByLineString, just do the required operation.
Print your result after each operation.
End

You can read for example 1024 bytes at a time.
char[] myBuffer = new char[512];
int bytesRead = 0;
BufferedReader in = new BufferedReader(new FileReader(reader));
while ((bytesRead = in.read(myBuffer,0,1024)) != -1)
{ ... }

Reading data from file without manually inputing the length it the array

Please I will like to adjust this code that reads integers from a file.
I will like the code to detect the number (n) of the dataset instead of having to put in figures manually as done below (4000 )
double[] tall = new double[4000];
public class Extracto {
public static void main(String[] args) throws IOException {
File fil = new File("C:\\Users\\Desktop\\kaycee2.csv");
FileReader inputFil = new FileReader(fil);
BufferedReader in = new BufferedReader(inputFil);
double[] tall = new double[4000];
String s = in.readLine();
int i = 0;
while (s != null) {
// Skip empty lines.
s = s.trim();
if (s.length() == 0) {
continue;
}
tall[i] = Double.parseDouble(s); // This is line 19.
// System.out.println(tall[i]);
s = in.readLine();
i++;
}
I am expecting the adjusted code to obtain the data length without manually putting it in like in as shown in the code below for the 4000 length.
double[] tall = new double[4000];

As Thomas mentioned, use a list, instead of an array.
File fil = new File("C:\\Users\\Desktop\\kaycee2.csv");
FileReader inputFil = new FileReader(fil);
BufferedReader in = new BufferedReader(inputFil);
ArrayList<Double> tall = new ArrayList<>();
while(in.ready()){
String s = in.readLine().trim();
if(!s.isEmpty()){
tall.add(Double.parseDouble(s);
}
}
your codes can be further compacted if you use a list.
also do add a try-catch in the event when the String read is not a number.

Creating array from file; getting error: Exception in thread "main" java.util.NoSuchElementException: No line found

All I am trying to do is create an array from numbers in a file... I'm pretty new to java so it may not be the most efficient way but I'm going off limited knowledge for now.
When I run it, I get the following message:
Exception in thread "main" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1540)
at CreateArray.main(CreateArray.java:27)
Here is my feeble attempt at the code:
import java.io.*;
import java.util.Scanner;
import java.util.ArrayList;
public class CreateArray
{
public static void main(String[] args) throws IOException
{
File file = new File("Numbers.txt");
Scanner inputFile = new Scanner(file);
// Find the number of lines in the file
int count = 0;
while (inputFile.hasNextLine())
{
String str = inputFile.nextLine();
count++;
}
// Create array
double[] numbers = new double[count];
// Add numbers to array
String str;
while (inputFile.hasNextLine());
{
for (int i = 0; i < count; i++)
{
str = inputFile.nextLine();
numbers[i] = Double.parseDouble(str);
}
}
// Display array
for (int i = 0; i < numbers.length; i++)
System.out.print(numbers[i] + " ");
}
}

When you write inputFile.hasNextLine() in your code using scanner, You have actually read a line from the file. As #tima said, you completed reading the file in the first while loop. Try looking at this java: about read txt file into array

Use Collection like ArrayList .So at time of File reading you don't need to declare size of array.
File file = new File("Numbers.txt");
Scanner inputFile = new Scanner(file);
List<Double> myList = new ArrayList<Double>();
while (inputFile.hasNextLine()) {
String str = inputFile.nextLine();
try {
myList.add(Double.parseDouble(str));
} catch (NumberFormatException e) {
// TODO: handle exception
}
}
for (Double data : myList) {
System.out.println(data);
}
And if you need array type ,then use this :-
Double data[] = new Double[myList.size()];
myList.toArray(data);
for (int i = 0; i < data.length; i++) {
System.out.println(data[i]);
}

How can I read only one thing in from a textfile?

I can read in from the file and am able to change the amount of lines given by changing the number in the for loop but I don't want all the numbers in my file displayed side by side like that. I need them all going down one by one randomly.
public class Assignment2 {
public static void main(String[] args) throws IOException
{
// Read in the file into a list of strings
BufferedReader reader = new BufferedReader(new FileReader("textfile.txt"));
List<String> lines = new ArrayList<String>();
String line = reader.readLine();
while( line != null ) {
lines.add(line);
line = reader.readLine();
}
// Choose a random one from the list
Random r = new Random();
for (int p = 0; p<3; p++)
{
String randomString = lines.get(r.nextInt(2));
System.out.println(lines);
}
}
}

I think what you want to print is
String randomString = lines.get(r.nextInt(2));
System.out.println(randomString);
To display only the first 20 random lines from this list of maybe 100
for (int i = 0; i < 20; i++) {
int rowNum = r.nextInt(lines.size ());
System.out.println(lines.get(rowNum);
}

reading text from .db file one line at a time

First of, I don't know how a.db file stores it data. If it does it in one line, or over many lines. Probably it does some difference from how to solve the problem.
the problem I'm facing is that I don't know how much data the file contains, only that it will be a date, time, and a description for x number of events in the form given below.
I have to convert the text into strings and put them in an array, but I don't know how to separate the text. When I tried I just ended up with one long string.
Can anybody help me?
01.01.2015|07:00-07:15|get up
01.01.2015|08:00|get to work
01.01.2015|08:00-16:00| work
01.01.2015|16:00-16:30| go home
what I want:
array[0] = "01.01.2015|07:00-07:15|get up"
array[1] = "01.01.2015|08:00|get to work"
array[2] = "01.01.2015|08:00-16:00| work"
array[3] = "01.01.2015|16:00-16:30| go home"
string table[] = new String [100];
void readFile(String fileName){
String read = "";
try {
x = new Scanner (new File(fileName));
}
catch (Exception e) {
}
while (x.hasNext()) {
read += x.nextLine();
}
}

Assuming here that your first code-block is in fact a copy of the file you're trying to read, you can do:
Scanner s = new Scanner(new File("file1.txt"));
List<String> lines = new LinkedList<>();
while (s.hasNextLine())
lines.add(s.nextLine());
If you really want to work with arrays and not lists, you can do
String[] table = lines.toArray(new String[lines.size()]);
after the loop.
If you're fortunate enough to work with Java 8, you can use:
List<String> lines = Files.lines(Paths.get("big.txt"))
.collect(Collectors.toList());
Again, if you really want to work with an array, you can convert the list using lines.toArray.

Since Java 8 you can use Paths.get(String first, String... more), Files.lines(Path path), and Stream.toArray():
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class SOPlayground {
public static void main(String[] args) throws Exception {
Path path = Paths.get("/tmp", "db.txt");
Object[] lines = Files.lines(path).toArray();
System.out.println(lines.length);
System.out.println(lines[0]);
System.out.println(lines[lines.length - 1]);
}
}
Output:
4
01.01.2015|07:00-07:15|get up
01.01.2015|16:00-16:30| go home

Try this solution using arrays:
code
Scanner sc = new Scanner(new File("file.txt"));
int index;
String[] arr = new String[1];
for(index = 0; sc.hasNextLine(); index++) {
arr = Arrays.copyOf(arr, index + 1);
arr[index] = sc.nextLine();
}
for(int i = 0; i<arr.length; i++) {
System.out.print(arr[i] + "\n");
}
I have used arr = Arrays.copyOf(arr, index + 1) to increase the size of the array to add next element.
Output
01.01.2015|07:00-07:15|get up
01.01.2015|08:00|get to work
01.01.2015|08:00-16:00| work
01.01.2015|16:00-16:30| go home

Well, it took me some houres. Thanx to all who lended a hand. This was what I got in the end.
int i=0;
String array [] new String [100]
try {
FileReader textFileReader= new FileReader (fileName);
BufferedReader textReader= new BufferedReader(textFileReader);
boolean continue = true;
while (continue) {
String text = textReader.readLine();
if (text != null){
array[i] = text;
i++;
}else {
continue = false;
}
}
}catch (Exception e) {}