We Keep Coding

How to split file input into 2 different arrays java

How do I split a file input text into 2 different array? I want to make n array for the names, and an array for the phone numbers. I managed to do the file input, but ive tried everything and cant seem to split the names and the numbers, then put it into 2 different arrays. Im noob pls help
here is how the phonebook.txt file looks like
Bin Arry,1110001111
Alex Cadel,8943257000
Poh Caimon,3247129843
Diego Amezquita,1001010000
Tai Mai Shu,7776665555
Yo Madow,1110002233
Caup Sul,5252521551
This Guy,7776663333
Me And I,0009991221
Justin Thyme,1113332222
Hey Oh,3939399339
Free Man,4533819911
Peter Piper,6480013966
William Mulock,9059671045
below is my code
import java.io.*;
import java.util.Scanner;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedReader;
public class demos {
public static void main(String[] args){
FileInputStream Phonebook;
DataInputStream In;
int i = 0;
String fileInput;
try
{
Phonebook = new FileInputStream("phonebook.txt");
FileReader fr = new FileReader("phonebook.txt");
BufferedReader br = new BufferedReader(fr);
String buffer;
String fulltext="";
while ((buffer = br.readLine()) != null) {
fulltext += buffer;
// System.out.println(buffer);
String names = buffer;
char [] Y ;
Y = names.toCharArray();
System.out.println(Y);
}}
catch (FileNotFoundException e)
{
System.out.println("Error - this file does not exist");
}
catch (IOException e)
{
System.out.println("error=" + e.toString() );
}

For a full functionnal (rather than imperative) solution I propose you this one :
public static void main(String[] args) throws IOException {
Object[] names = Files.lines(new File("phonebook.txt").toPath()).map(l -> l.split(",")[0]).toArray();
Object[] numbers = Files.lines(new File("phonebook.txt").toPath()).map(l -> l.split(",")[1]).toArray();
System.out.println("names in the file are : ");
Arrays.stream(names).forEach(System.out::println);
System.out.println("numbers in the file are : ");
Arrays.stream(numbers).forEach(System.out::println);
}
output
names in the file are :
Bin Arry
Alex Cadel
Poh Caimon
Diego Amezquita
Tai Mai Shu
Yo Madow
Caup Sul
This Guy
Me And I
Justin Thyme
Hey Oh
Free Man
Peter Piper
William Mulock
numbers in the file are :
1110001111
8943257000
3247129843
1001010000
7776665555
1110002233
5252521551
7776663333
0009991221
1113332222
3939399339
4533819911
6480013966
9059671045
As you can see functionnal programming is short and smart …. and easy when you're accustomed

You could simplify it if you are using Java 8:
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.ArrayList;
public class Test {
static ArrayList<String> names = new ArrayList<String>();
static ArrayList<String> numbers = new ArrayList<String>();
/**
* For each line, split it on the comma and send to splitNameAndNum()
*/
public static void main(String[] args) throws IOException {
Files.lines(new File("L:\\phonebook.txt").toPath())
.forEach(l -> splitNameAndNum(l.split(",")));
}
/**
* Accept an array of length 2 and put in the proper ArrayList
*/
public static void splitNameAndNum(String[] arr) {
names.add(arr[0]);
numbers.add(arr[1]);
}
}
And in Java 7:
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
public class Test {
static ArrayList<String> names = new ArrayList<String>();
static ArrayList<String> numbers = new ArrayList<String>();
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("L:\\phonebook.txt")));
String line;
while ((line = br.readLine()) != null) {
splitNameAndNum(line.split(","));
}
}
/**
* Accept an array of length 2 and put in the proper ArrayList
*/
public static void splitNameAndNum(String[] arr) {
names.add(arr[0]);
numbers.add(arr[1]);
}
}

Calling method from different class (different than other questions)

So I'm relatively new to java and I'm trying to use a method from a different class inside my main.
The method I'm using to pull doesn't contain any data initially but pulls the data from a text doc.
I've included the code that calls the other class method that loads the data from the file. It sill doesn`t work, so where is my mistake?
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class FinalRobert {
public static void main(String[] args) {
//output of animalList class here
}
Here is the class I'm trying to pull from:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;
public class animalList {
public void animalDetails () {
int i = 0;
String animalInfo = "C:/Users/Robert/Documents/animals.txt";
String animalHabitat = "‪C:/Users/Robert/Documents/habitats.txt";
try {
File animalFile = new File(animalInfo);
FileReader animalReader = new FileReader(animalFile);
BufferedReader animalList = new BufferedReader (animalReader);
StringBuilder animalDetailList = new StringBuilder();
String line;
while ((line = animalList.readLine()) != null) {
for (i = 0; i <4 ; i++) {
System.out.println(line);
animalList.readLine();
}
}
animalReader.close();
System.out.println(animalDetailList.toString());
}
catch (IOException e) {
}
}
}
So I want to have the output of the animalList class in my main, but I don't know how to bring it over because I'm not necessarily bring over variable, but a process. The full thing should bring the first line and four past it (so a total of the first five lines in the doc). Hopefully that makes things easier to see my problem.

This is a mcve of AnimalList :
public class AnimalList {//use java naming convention
public void animalDetails () {
//mcve should be runnable. The problem you ask help with is not
//reading from file, so remove file reading functionality to make it mcve
StringBuilder animalDetailList = new StringBuilder();
animalDetailList.append("Family: Cats").append("\n")
.append("Type : Panther").append("\n")
.append("Weight: 250kg").append("\n")
.append("Color : Pink");
System.out.println(animalDetailList.toString());
}
}
Invoke its method from another class:
public class FinalRobert {
public static void main(String[] args) {
//to invoke animalDetails() method use
AnimalList aList = new AnimalList();
aList.animalDetails();
//if you do not need the aList refrence you could use
//new AnimalList().animalDetails();
}
}
Output
Family: Cats Type : Panther Weight: 250kg Color :
Pink

I hope this might help you.
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class FinalRobert {
public static void main(String[] args) {
animalList list = new animalList();
list.animalDetails();
}
}
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;
public class animalList {
public String animalDetails () {
int i = 0;
String output="";
String animalInfo = "C:/Users/Robert/Documents/animals.txt";
String animalHabitat = "‪C:/Users/Robert/Documents/habitats.txt";
try {
File animalFile = new File(animalInfo);
FileReader animalReader = new FileReader(animalFile);
BufferedReader animalList = new BufferedReader (animalReader);
String line;
while ((line = animalList.readLine()) != null & i<4) {
System.out.println(line);
output = output + "\n"+ line;
i++;
}
animalReader.close();
System.out.println(output);
}
catch (IOException e) {
}
return output;
}
}

How to get key taken from data taken from website API

I am currently coding in Java using Eclipse. I am trying to obtain the value of the key "high" given the data
{"high": "639.00000", "last": "634.94000", "timestamp": "1476220216", "bid": "634.94000", "vwap": "630.07099", "volume": "7939.75947138", "low": "613.83000", "ask": "636.50000", "open": "616.37000"}
which I get from this address : "https://www.bitstamp.net/api/v2/ticker/btcusd/"
So far, I got this code:
package JsonSimpleExample;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import org.json.simple.*;
public class JsonSimpleExample {
public static void main(String[] args) throws IOException {
URL url = new URL("https://www.bitstamp.net/api/v2/ticker/btcusd/");
URLConnection con = url.openConnection();
InputStream is =con.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
System.out.println(br.readLine());
}
}
A possible solution is to write the data I get from the website into a file and input each key, value pair into a hashmap and call for the value but that seems very highly redundant. Is there any way to directly obtain a value for a key with the data that the API gives me?

Simple you need to add json library also.
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;
import org.json.JSONObject;
/**
*
* #author BTACTC
*/
public class JsonExample {
URL url;
String str;
Scanner scan;
JSON json;
public JsonExample() throws MalformedURLException, IOException {
url = new URL("https://www.bitstamp.net/api/v2/ticker/btcusd/");
scan = new Scanner(url.openStream());
str = new String();
while (scan.hasNext()) {
str += scan.nextLine();
}
System.out.println(str);// checking the data is now in string
JSONObject obj = new JSONObject(str);
System.out.println(obj.getString("high"));;
}
public static void main(String[] args) throws IOException {
JsonExample JE = new JsonExample();
}
}

Java - Merging two sets of code

I've written two separate pieces of code. Now I want to merge both pieces of code. Now one part opens a text file and displays the contents of the text file and the second piece of code validates manually entered postcodes. Now I want to read a text file and then automatically validate postcodes within the text file. Not sure how I can merge them. Any questions please ask as I'm stuck.
package postcodesort;
import java.util.*;
import java.util.Random;
import java.util.Queue;
import java.util.TreeSet;
import java.io.File;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.LinkedList;
import java.util.StringTokenizer;
public class PostCodeSort
{
Queue<String> postcodeStack = new LinkedList<String>();
public static void main(String[] args) throws IOException
{
FileReader fileReader = null;
// Create the FileReader object
try {
fileReader = new FileReader("postcodes1.txt");
BufferedReader br = new BufferedReader(fileReader);
String str;
while((str = br.readLine()) != null)
{
System.out.println(str + "");
}
}
catch (IOException ex)
{
// handle exception;
}
finally
{
fileReader.close();
}
// Close the input
}
}
Second part that manually validates postcodes:
List<String> zips = new ArrayList<String>();
//Valid ZIP codes
zips.add("SW1W 0NY");
zips.add("PO16 7GZ");
zips.add("GU16 7HF");
zips.add("L1 8JQ");
//Invalid ZIP codes
zips.add("Z1A 0B1");
zips.add("A1A 0B11");
String regex = "^[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}$";
Pattern pattern = Pattern.compile(regex);
for (String zip : zips)
{
Matcher matcher = pattern.matcher(zip);
System.out.println(matcher.matches());
}

You should create a class called something like ZipCodeValidator that contains the functionality of your second snippet. It will look something like this
public class ZipCodeValidator {
private static String regex = "^[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}$";
private static Pattern pattern = Pattern.compile(regex);
public boolean isValid(String zipCode) {
Matcher matcher = pattern.matcher(zip);
return matcher.matches();
}
}
Then you can create an instance of this class
ZipCodeValidator zipCodeValidator = new ZipCodeValidator();
and then use it in your main method
boolean valid = zipCodeValidator.isValid(zipCode);

Merging your question and the answer by #hiflyer I posted this answer, this makes an assumption that the file postcodes1.txt has all the zip codes in separate lines.
package postcodesort;
import java.util.*;
import java.util.Random;
import java.util.Queue;
import java.util.TreeSet;
import java.io.File;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.LinkedList;
import java.util.StringTokenizer;
public class PostCodeSort
{
Queue<String> postcodeStack = new LinkedList<String>();
public static void main(String[] args) throws IOException
{
FileReader fileReader = null;
ZipCodeValidator zipCodeValidator = new ZipCodeValidator();
// Create the FileReader object
try {
fileReader = new FileReader("postcodes1.txt");
BufferedReader br = new BufferedReader(fileReader);
String str;
while((str = br.readLine()) != null)
{
if(zipCodeValidator.isValid(str)){
System.out.println(str + " is valid");
}
else{
System.out.println(str + " is not valid");
}
}
}
catch (IOException ex)
{
// handle exception;
}
finally
{
fileReader.close();
}
}
}
public class ZipCodeValidator {
private static String regex = "^[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}$";
private static Pattern pattern = Pattern.compile(regex);
public boolean isValid(String zipCode) {
Matcher matcher = pattern.matcher(zip);
return matcher.matches();
}
}

String Tokenizing error occurs

there is a text file which we read from it , then we want to write it after some little changes to othere text file, but the question is that why it has different results if we use
System.out.println and when we use pwPaperAuthor.println?
the code is like :
package cn.com.author;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
//input:"IndexAuthors1997-2010.txt"
//output:"PaperAuthor1997-2010.txt"
public class PaperAuthors {
public static void main(String[] args) {
BufferedReader brIndexAuthors = null;
BufferedWriter bw = null;
PrintWriter pwPaperAuthor = null;
try {
brIndexAuthors = new BufferedReader(new InputStreamReader(
new FileInputStream("IndexAuthors1997-2010.txt")));
bw = new BufferedWriter(new FileWriter(new File(
"PaperAuthor1997-2010.txt")));
pwPaperAuthor = new PrintWriter(new OutputStreamWriter(
new FileOutputStream("PaperAuthor1997-2010.txt")));
/*
* line = brIndexAuthors.readLine();
*
* element=line.split("#"); String author=null; StringTokenizer st =
* new StringTokenizer(element[1],","); while(st.hasMoreTokens()) {
* author = st.nextToken(); pwPaperAuthor.println(element[0] + "+" +
* author); //~i++; }
*/
String line = null;
String element[] = new String[3];
String author = null;
int i = 0;
while ((line = brIndexAuthors.readLine()) != null) {
element = line.split("##");
StringTokenizer st = new StringTokenizer(element[1], ",");
int num=st.countTokens();
while (st.hasMoreTokens()) {
author = st.nextToken();
pwPaperAuthor.println(element[0]+"#"+author+"#"+element[2]);
bw.write(element[0] + "#" + author + "#" + element[2]);
bw.newLine();
System.out.println(element[0]+"#"+author+"#"+element[2]);
i++;
}
}
} catch (IOException e) {
e.printStackTrace();
} finally {
}
}
}
Ouput
if
System.out.println(element[0]+"#"+author+"#"+element[2]);------>620850#Henk Ern
if
pwPaperAuthor.println(element[0]+"#"+author+"#"+element[2]);
----->620850#Henk Ernstblock#2001

There's no way you can read a file and write to it in the same loop, using the stream-based API. You will have to create a new file and copy everything that's the same, adding what's new. What you are doing now has unpredictable behavior. If you still want to read and write at the same time, you'll have to use the RandomAccessFile, but that's quite a bit more complicated.