Develop Reference

Rename file using scanners

I need to rename the file temp.txt later on in my code. I tried doing this with the newFile = new File(name); line, but this just created a new file entirely. Could you point me in the right direction here?
public static File InputOutput (Scanner console, int in_Out) throws
FileNotFoundException {
//<editor-fold>
String name = "newName";
String line = "";
String in_OutText = "";
File newFile = new File("temp.txt");
for (int i = 0; i <= in_Out; i++) {
if (i == 0) {
in_OutText = "Input";
} else {
in_OutText = "Output";
}
System.out.print(in_OutText + " file name: ");
name = console.next();
if (i == 1) {
newFile = new File(name);
}
}
PrintStream inputCopy = new PrintStream(newFile)
Scanner input = new Scanner(name);
while (input.hasNextLine()) {
line = input.nextLine();
inputCopy.println(line);
inputCopy.println("WORKED");
}
return newFile;
}
Thanks!

How to read integers from a file that are separated with semi colon?

So in my codes, I am trying to read a file that is like:
100
22
123;22
123 342;432
but when it outputs it would include the ";" ( ex. 100,22,123;22,123,342;432} ).
I am trying to make the file into an array ( ex. {100,22,123,22,123...} ).
Is there a way to read the file, but ignore the semicolons?
Thanks!
public static void main(String args [])
{
String[] inFile = readFiles("ElevatorConfig.txt");
for ( int i = 0; i <inFile.length; i = i + 1)
{
System.out.println(inFile[i]);
}
System.out.println(Arrays.toString(inFile));
}
public static String[] readFiles(String file)
{
int ctr = 0;
try{
Scanner s1 = new Scanner(new File(file));
while (s1.hasNextLine()){
ctr = ctr + 1;
s1.next();
}
String[] words = new String[ctr];
Scanner s2 = new Scanner(new File(file));
for ( int i = 0 ; i < ctr ; i = i + 1){
words[i] = s2.next();
}
return words;
}
catch(FileNotFoundException e)
{
return null;
}
}

public static String[] readFiles(String file)
{
int ctr = 0;
try{
Scanner s1 = new Scanner(new File(file));
while (s1.hasNextLine()){
ctr = ctr + 1;
s1.next();
}
String[] words = new String[ctr];
Scanner s2 = new Scanner(new File(file));
for ( int i = 0 ; i < ctr ; i = i + 1){
words[i] = s2.next();
}
return words;
}
catch(FileNotFoundException e)
{
return null;
}
}
Replace this by
public static String[] readFiles(String file) {
List<String> retList = new ArrayList<String>();
Scanner s2 = new Scanner(new File(file));
for ( int i = 0 ; i < ctr ; i = i + 1){
String temp = s2.next();
String[] tempArr = se.split(";");
for(int k=0;k<tempArr.length;k++) {
retList.add(tempArr[k]);
}
}
return (String[]) retList.toArray();
}

Use regex. Read the entire file into a String (read each token as a String and append a blank space after each token in the String) and then split it at blank spaces and semi colons.
String x <--- contains all contents of the file
String[] words = x.split("[\\s\\;]+");
The contents of words[] are:
"100", "22", "123", "22", "123", "342", "432"
Remember to parse them to int before using as numbers.

Simple way to use BufferedReader Read line by line then split by ;
public static String[] readFiles(String file)
{
BufferedReader br = new BufferedReader(new FileReader(file)))
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null) {
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
}
String allfilestring = sb.toString();
String[] array = allfilestring.split(";");
return array;
}

You can use split() to split the string into array according to your requirement using regex.
String s; // string you have read from the file
String[] s1 = s.split(" |;"); // s1 contains the strings separated by space and ";"
Hope it helps

Keep the code for counting the size of the array.
I would just change the way you input your values.
for (int i = 0; i < ctr; i++) {
words[i] = "" + s1.nextInt();
}

Another option is to replace all non digit characters in your complete file string with a space. That way any non number character is ignored.
BufferedReader br = new BufferedReader(new FileReader(file)))
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null) {
sb.append(line);
line = br.readLine();
}
String str = sb.toString();
str = str.replaceAll("\\D+"," ");
Now you have a string with numbers separated by spaces, we can tokenize them into number strings.
String[] final = str.split("\\s+");
then convert to int datatypes.

How to put Output in ArrayList from a file in Local

I am trying to segregate my data into multiple array list, so that I can use them later-on in my code. But I am not able to put my data in array list.
My code is about segregating the data into three array list of different Subjects (Example:Physics,chemistry) as per various filters, which you will find in my code.
Input data file:
1|150|20150328|20150406|Physics|1600|1600|2|68|92
2|152|20150328|20150406|Physics|1600|1500|2|68|89
3|153|20150328|20150406|Physics|1600|1500|2|68|60
4|155|20150328|20150406|Physics|1600|1600|2|68|72
5|161|20150328|20150406|Chemistry|1600|1600|2|68|77
Here's my code:
Public Class filter{
public static void main(String args[])
BufferedReader in= null;
BufferedWriter out= null;
String in_line;
String PrevRollNo= "";
int PrevDate= 0;
ArrayList<transaction> PhysicsList= new ArrayList<transaction>();
ArrayList<transaction> scList= new ArrayList<transaction>();
ArrayList<transaction> Chemistry= new ArrayList<transaction>();
try{
in = new BufferedReader(new FileReader(Path for input file));
File out_file= new File(Path for output file);
if(!out_file.exists())
{
(!out_file.createNewFile();
}
FileWriter fw=new FileWriter(out_file);
out= new BufferedWriter(fw);
while ((in_line=in.readline())!=null)
{
Transaction transact=new Transaction(in_line);
if(transact.RollNo.equals(PrevRollNo))
{
if(transact.subject.equals("Physics")&& transact.Prs_Date= PrevDate
{
PhysicsList.add(transact);
}
else if(transact.subject.equals("Physics")&&transact.wk_date != PrevDate}
Iterator<Transaction> it;
if(!transact.RoomNo.equals("102")&&!transact.lcl_RoomNo.equals("102");
{
it= scList.iterator();
while(it.hasnext())
{
Transaction sc= it.next();
if(sc.lcl_RoomNo.equals(transact.RoomNo) && sc.l1 equals(tansact.l1) && sc.l2 equals(transact.l2)
if(sc.marks==transact.marks)
{
transact.srsfound= true;
}
else
{
System.out.print.ln( "not found");
}
scList.remove(sc))
out.write(in_line);
break;
}}}}
Static Class Transaction
{
Public String RollNo, Subject, RoomNo, lcl_RoomNo, l1, l2;
Public int wk_date, prs_date;
Public double marks , amt;
Public boolean srcfound, tgtfound;
Public Transaction(String in_line)
{
String [] SplitData= in_line.split("\\|");
RollNo = SplitData[1];
Subject = SplitData[4]
RoomNo = SplitData[5];
lcl_RoomNo = SplitData[6];
l1 = SplitData[7];
l2 = SplitData[8];
wk_date = SplitData[3];
prs_date = SplitData[2];
marks = Double.parsedouble(SplitData[9]);
amt = Double.parsedouble(SplitData[]);
srcfound = false;
tgtfound = false;
}
Kindly help with your expertise.

Use Java 8 NIO and Streams. It will ease the job.
Files.lines(Paths.get("fileName.txt")).map(line -> {
String[] tokens = line.split("|");
//tokens contains individual elements of each line. Add your grouping logic on tokens array
}

I agree with the other answer in some ways. NIO should be used, it makes it a lot easier. However, I would avoid streams and instead use the readAllLines method like so:
try{
List<String> filecontents = new String(Files.readAllLines(file.toPath()); //file is the object to read from.
for(int i = 0; i < filecontents.size(); i++){
String line = lines.get(i);
//New code starts here
if(!line.contains("|") continue; //Ignore that line
//New code ends here
String[] array = line.split("|");
ArrayList<String> list = new ArrayList<String>();
for(int a = 0; a < array.length; a++){
String part = array[a];
list.add(part);
}
Transaction t = new Transaction(line);
if(line.contains("Physics") PlysicsList.add(t);
else if(line.contains("Chemistry") Chemistry.add(t);
else{ //Do nothing}
}
}catch(IOException e){
e.printStackTrace();
}
EDIT: I added a check in there. The reason the first and last lines may not be working is if the lines that are being parsed are not being parsed properly. See if this fixes your issue

Trying to read a file and put values in an array

I need to read certain portions of a file and put them into their correct array.
public static void load(String fileName, String[] itemNumbers,
String[] itemNames, double[] priceOfItem, int[] quantity) throws IOException{
int i = 0;
File inFile = new File(fileName);
Scanner reader = new Scanner(inFile);
while(reader.hasNext()){
itemNumbers[i] = reader.next();
itemNames[i] = reader.next();
priceOfItem[i] = reader.nextDouble();
quantity[i] = reader.nextInt();
i++;
}
//This is just to see if it worked
System.out.println(itemNumbers[i]);
System.out.println(itemNames[i]);
System.out.println(priceOfItem[i]);
System.out.println(quantity[i]);
}
Here is the file I'm reading.
E3233 CordlessDrill 129.99 12
W2321 WindowSealer 3.39 84
The arrays are in order with the file portions.
When I run this I receive the following
null
null
0.0
0

Make sure it says
while(reader.hasNextLine())

have you tried using FileReader?
public static void load(String fileName, String[] itemNumbers,
String[] itemNames, double[] priceOfItem, int[] quantity) throws IOException{
File inFile = new File(fileName);
char[] cbuf = new char[(int) inFile.length()];
FileReader r = new FileReader(inFile);
r.read(cbuf);
String finalString = String.valueOf(cbuf);
String[] lines = finalString.split("\n");
itemNumbers = new String[lines.length];
itemNames = new String[lines.length];
priceOfItem = new double[lines.length];
quantity = new int[lines.length];
for(int i = 0; i < lines.length; i++){
String line = lines[i].replace("\n", "");
String[] values = line.split(" ");
String itemNumber = values[0];
String itemName = values[1];
double price = Double.parseDouble(values[2]);
int quant = Integer.parseInt(values[3].replace(String.valueOf((char)13), "").replace(" ", "").replace("\"", ""));
itemNumbers[i] = itemNumber;
itemNames[i] = itemName;
priceOfItem[i] = price;
quantity[i] = quant;
}
r.close();
for(int i = 0; i < itemNames.length; i++){
System.out.println(itemNumbers[i]);
System.out.println(itemNames[i]);
System.out.println(priceOfItem[i]);
System.out.println(quantity[i]);
System.out.println("\n");
}
}
this method relies on using spaces in your file, I would add comma's and end lines with semicolons to be safe, but if you maintain the same format this should work.

Reading in information into separate arrays

I've been having some difficulties reading in information from a file into separate arrays. An example of the information in the file is:
14 Barack Obama:United States
17 David Cameron:United Kingdom
27 Vladimir Putin:Russian Federation
19 Angela Merkel:Germany
While I can separate the integers into an array, I am having trouble creating an array for the names and an array for the countries. This is my code thus far:
import java.util.*;
import java.io.*;
public class leadRank {
public static void main(String[] args) throws FileNotFoundException {
int size;
Scanner input = new Scanner(new File("names.txt"));
size = input.nextInt();
int[] rank = new int[size];
for (int i = 0; i < rank.length; i++) {
rank[i] = input.nextInt();
input.nextLine();
}
String[] name = new String[size];
for (int i = 0; i <name.length; i++) {
artist[i] =
I think that I would have to read in the line as a string and use indexOf to find the colon in order to start a new array but I'm unsure as to how to execute that.

I just tried to solve your problem in my ways. It was just for a time pass. Hopes this may helps you.
import java.util.*;
import java.io.*;
public class leadRank {
public static void main(String[] args) throws FileNotFoundException {
int size;
File file = new File("names.txt");
FileReader fr = new FileReader(file);
String s;
LineNumberReader lnr = new LineNumberReader(new FileReader(file));
lnr.skip(Long.MAX_VALUE);
size = lnr.getLineNumber()+1;
lnr.close();
int[] rank = new int[size];
String[] name = new String[size];
String[] country = new String[size];
try {
BufferedReader br = new BufferedReader(fr);
int i=0;
while ((s = br.readLine()) != null) {
String temp = s;
if(temp.contains(":")){
String[] splitres = temp.split(":");
String sub = splitres[0];
rank[i] = Integer.parseInt(sub.substring(0,sub.indexOf(" "))); // Adding rank to array rank[]
name[i] = sub.substring(sub.indexOf(" "), sub.length()-1); // Adding name to array name[]
country[i] = splitres[1]; // Adding the conutries to array country[]
}
i++;
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

This is a bit more efficient because it goes through the file only once.
public static void main(String[] args) throws FileNotFoundException {
// create an array list because the size of the array is still not know
ArrayList<Integer> ranks = new ArrayList<Integer>();
ArrayList<String> names = new ArrayList<String>();
ArrayList<String> countries = new ArrayList<String>();
// read the input file
Scanner input = new Scanner(new File("names.txt"));
// read each line
while (input.hasNext()) {
String wholeLine = input.nextLine();
// get the index of the first space
int spaceIndex = wholeLine.indexOf(" ");
// parse the rank
int rank;
try {
rank = Integer.parseInt(wholeLine.substring(0, spaceIndex));
} catch (NumberFormatException e) {
rank = -1;
}
// parse the name & country
String[] tokens = wholeLine.substring(spaceIndex + 1).split(":");
String name = tokens[0];
String country = tokens[1];
// add to the arrays
ranks.add(rank);
names.add(name);
countries.add(country);
}
// get your name and country arrays if needed
String[] nameArr = names.toArray(new String[]{});
String[] countryArr = countries.toArray(new String[]{});
// the rank array has to be created manually
int[] rankArr = new int[ranks.size()];
for (int i = 0; i < ranks.size(); i++) {
rankArr[i] = ranks.get(i).intValue();
}
}