I have got two text files with data in the following format
data.txt file as following format
A 10
B 20
C 15
data1.txt file is in format (start node,end node, distance):
A B 5
A C 10
B C 20
I am trying to implement a search strategy, for that I need to load the data from data.txt and ONLY the start node and end node from data1.txt (i.e. I dont need the distance). I need to store this information in a stack as I think it would be a best data structure for implementing greedy search.
Actually I am not sure how to get started with file I/O to read these files and store them in array to implement greedy search. So I would highly appreciate any starting idea on how to proceed.
I am new to this, so please bear with me. Any help is much appreciated. Thanks.
EDIT:
Here is what I have got till now
String heuristic_file = "data.txt";
try
{
FileReader inputHeuristic = new FileReader(heuristic_file);
BufferedReader bufferReader = new BufferedReader(inputHeuristic);
String line;
while ((line = bufferReader.readLine()) != null)
{
System.out.println(line);
}
bufferReader.close();
} catch(Exception e) {
System.out.println("Error reading file " + e.getMessage());
}
My approach, doesn't differ fundamentally from the others. Please regard the try/catch/finally blocks. Always put the closing statements into the finally block, so the opened file is guaranteed to be closed, even if an exception was thrown while reading the file.
The part between the two //[...] could surely be done more efficient. Maybe reading the whole file in one take and then parsing the text backwards and searching for a line-break? Maybe a Stream-API supports to set the reading position. I honestly don't know. I didn't need that, up to now.
I chose to use the verbose initialization of the BufferedReader, because then you can specify the expected encoding of the file. In your case it doesn't matter, since your files do not contain symbols out of the standard ASCII range, but I believe it's a semi-best-practice.
Before you ask: r.close() takes care of closing the underlying InputStreamReader and FileInputStream in the right order, till all readers and streams are closed.
public static void readDataFile(String dir, String file1, String file2)
throws IOException
{
File datafile1 = new File(dir, file1);
File datafile2 = new File(dir, file2);
if (datafile1.exists())
{
BufferedReader r = null;
try
{
r = new BufferedReader(
new InputStreamReader(
new FileInputStream(datafile1),
"UTF-8"
)
);
String row;
Stack<Object[]> s = new Stack<Object[]>();
String[] pair;
Integer datapoint;
while((row = r.readLine()) != null)
{
if (row != null && row.trim().length() > 0)
{
// You could use " " instead of "\\s"
// but the latter regular expression
// shorthand-character-class will
// split the row on tab-symbols, too
pair = row.split("\\s");
if (pair != null && pair.length == 2)
{
datapoint = null;
try
{
datapoint = Integer.parseInt(pair[1], 10);
}
catch(NumberFormatException f) { }
// Later you can validate datapairs
// by using
// if (s.pop()[1] != null)
s.add(new Object[] { pair[0], datapoint});
}
}
}
}
catch (UnsupportedEncodingException e1) { }
catch (FileNotFoundException e2) { }
catch (IOException e3) { }
finally
{
if (r != null) r.close();
}
}
// Do something similar with datafile2
if (datafile2.exists())
{
// [...do the same as in the first try/catch block...]
String firstrow = null, lastrow = null;
String row = null;
int i = 0;
do
{
lastrow = row;
row = r.readLine();
if (i == 0)
firstrow = row;
i++;
} while(row != null);
// [...parse firstrow and lastrow into a datastructure...]
}
}
use split
while ((line = bufferReader.readLine()) != null)
{
String[] tokens = line.split(" ");
System.out.println(line + " -> [" + tokens[0] + "]" + "[" + tokens[1] + "][" + tokens[2] + "]");
}
if you must have this in an array you can use the following:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
public class NodeTest {
public static void main(String[] args) throws ParseException {
try {
File first = new File("data.txt");
File second = new File("data1.txt");
Node[] nodes1 = getNodes(first);
Node[] nodes2 = getNodes(second);
print(nodes1);
print(nodes2);
}
catch(Exception e) {
System.out.println("Error reading file " + e.getMessage());
}
}
public static final void print(Node[] nodes) {
System.out.println("======================");
for(Node node : nodes) {
System.out.println(node);
}
System.out.println("======================");
}
public static final Node[] getNodes(File file) throws IOException {
FileReader inputHeuristic = new FileReader(file);
BufferedReader bufferReader = new BufferedReader(inputHeuristic);
String line;
List<Node> list = new ArrayList<Node>();
while ((line = bufferReader.readLine()) != null) {
String[] tokens = line.split(" ");
list.add(new Node(tokens[0], tokens[1]));
}
bufferReader.close();
return list.toArray(new Node[list.size()]);
}
}
class Node {
String start;
String end;
public Node(String start, String end){
this.start = start;
this.end = end;
}
public String toString() {
return "[" + start + "][" + end + "]";
}
}
Something like this?
HashSet<String> nodes = new HashSet<String>();
try(BufferedReader br = new BufferedReader(new FileReader("data.txt"))) {
String line = br.readLine();
while (line != null) {
String[] l = line.split(" ");
nodes.add(l[0]);
line = br.readLine();
}
}
try(BufferedReader br = new BufferedReader(new FileReader("data1.txt"))) {
String line = br.readLine();
while (line != null) {
String[] l = line.split(" ");
if (nodes.contains(l[0]) || nodes.contains(l[1]))
// Do whatever you want ...
line = br.readLine();
}
}
Related
So I'm trying to use a BufferedReader to split a text file into 2 different arrays, I've written some code but I'm not sure where to go from here.
I know how to populate an array, but i just cant seem to get the specific lines.
So, one array for NEW_OFFICE containing only the numbers, and one for MAIN_ADDRESS containing only the numbers below it.
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader("myDelivery.txt"));
String read = null;
while ((read = in.readLine()) != null) {
String words = read.split("NEW_OFFICE")[0];
}
} catch (IOException e) {
System.out.println("There was a problem: " + e);
e.printStackTrace();
} finally {
try {
in.close();
} catch (Exception ignored) { }
}
This is the text file:
NEW_OFFICE
-92.48392883 52.96531732
-2.483984994 92.48392883
MAIN_ADDRESS
-1.207614869 52.98908196
NEW_OFFICE always is the first line, and always has two lines below
it, the same goes for MAIN_ADDRESS it always has one line below it.
NEW_OFFICE & MAIN_ADDRESS can't appear more than once.
Based on your comment mentioned above, given below is the solution:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
public class Main {
public static void main(String[] args) throws IOException {
String[][] office = new String[2][2];
String[][] main = new String[1][2];
try (BufferedReader in = new BufferedReader(new FileReader("myDelivery.txt"))) {
String read;
while ((read = in.readLine()) != null) {
if (read.equalsIgnoreCase("NEW_OFFICE")) {
// Read next two lines
for (int i = 0; i < 2; i++) {
if ((read = in.readLine()) != null) {
office[i] = read.split("\\s+");
}
}
} else if (read.equalsIgnoreCase("MAIN_ADDRESS")) {
// Read next line
if ((read = in.readLine()) != null) {
main[0] = read.split("\\s+");
}
}
}
}
// Display office[][]
System.out.println("Displaying office:");
for (String[] officeData : office) {
System.out.println(Arrays.toString(officeData));
}
// Display main[][]
System.out.println("Displaying main:");
for (String[] mainData : main) {
System.out.println(Arrays.toString(mainData));
}
}
}
Output:
Displaying office:
[-92.48392883, 52.96531732]
[-2.483984994, 92.48392883]
Displaying main:
[-1.207614869, 52.98908196]
Notes:
\\s+ is for splitting the line on space(s).
Use try-with-resources syntax to simplify your code.
.split() does take a string, but it should be a regex, not the substring that you want to split it on. You want to change your code like this:
try (BufferedReader in = new BufferedReader(new FileReader("x.txt"))) {
String read;
String office = "";
while ((read = in.readLine()) != null) {
if (read.contains("NEW_OFFICE")) {
office = "NEW_OFFICE";
} else if (read.contains("MAIN_ADDRESS")) {
office = "MAIN_ADDRESS";
} else {
System.out.println(office + " : " + read);
}
}
} catch (IOException e) {
e.printStackTrace();
}
I have also changed your try with try-with-resources so you don't have to worry about closing the resource.
I´d go with somethin like this.
Please be aware that I don´t have an IDE right now so this is basically pseudo code:
try (BufferedReader in = new BufferedReader(new FileReader("x.txt"))) {
String line = null;
boolean isOffice = false;
ArrayList<double> officeInts = new ArrayList<double>();
ArrayList<double> addressInts = new ArrayList<double>();
while ((line = in.readLine()) != null) {
if (line.contains("NEW_OFFICE")) {
isOffice = true;
continue;
} else if (line.contains("MAIN_ADDRESS")) {
isOffice = false;
continue;
}
for(String s : line.split(" "){
double num = Double.parseDouble(s);
if(isOffice) {
officeInts.add(num);
} else {
addressInts.add(num);
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
I am dividing my file into chunks but only problem i am facing is,
i have .srt file, but while doing chunks, it's cutting the characters i.e in first .srt file it's like 00:26:20,230 --> . in next file it continuing the next time stamp 00:27:40,343.
I need to check the timestamp to be complete and then next full subtitle sentence too. i.e if it's cutting the subtitle timesstamp or dialogue in in file, that tect to be append to next file. Please suggest me how can i achieve.
I am trying like below,
String FilePath = "/Users/meh/Desktop/escapeplan.srt";
FileInputStream fin = new FileInputStream(FilePath);
System.out.println("size: " +fin.getChannel().size());
long abc = 0l;
abc = (fin.getChannel().size())/3;
System.out.println("6: " +abc);
System.out.println("abc: " +abc);
//FilePath = args[1];
File filename = new File(FilePath);
long splitFileSize = 0,bytefileSize=0;
if (filename.exists()) {
try {
//bytefileSize = Long.parseLong(args[2]);
splitFileSize = abc;
Splitme spObj = new Splitme();
spObj.split(FilePath, (long) splitFileSize);
spObj = null;
} catch (Exception e) {
e.printStackTrace();
}
} else {
System.out.println("File Not Found....");
}
public void split(String FilePath, long splitlen) {
long leninfile = 0, leng = 0;
int count = 1, data;
try {
File filename = new File(FilePath);
InputStream infile = new BufferedInputStream(new FileInputStream(filename));
data = infile.read();
System.out.println("data");
System.out.println(data);
while (data != -1) {
filename = new File("/Users/meh/Documents/srt" + count + ".srt");
//RandomAccessFile outfile = new RandomAccessFile(filename, "rw");
OutputStream outfile = new BufferedOutputStream(new FileOutputStream(filename));
while (data != -1 && leng < splitlen) {
outfile.write(data);
leng++;
data = infile.read();
}
leninfile += leng;
leng = 0;
outfile.close();
changeTimeStamp(filename, count);
count++;
}
} catch (Exception e) {
e.printStackTrace();
}
}
i am trying to check the time stamp is in correct format or not. Then i need to check next line to be a dialogue and then the next line to be empty line. then it can stop chunk or else it should append the text from the previous chunk to next chunk file in the beginning of line . so that it may get in correct format.
I tried checking the format like,
while ((strLine = br.readLine()) != null) {
String[] atoms = strLine.split(" --> ");
if (atoms.length == 1) {
out.write(strLine + "\n");
} else {
String startTS = atoms[0];
String endTS = atoms[1];
System.out.print("sri atmos start" + startTS);
System.out.print("sri atmos end" + endTS);
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss,SSS");
sdf.setLenient(false);
try
{
sdf.parse(startTS);
sdf.parse(endTS);
System.out.println("Valid time");
System.out.println("File path" + srcFileNm);
}
catch(Exception e) {
System.out.println("Invalid time");
System.out.println("Exception start" + startTS);
System.out.println("Exception end" + endTS);
}
}
some screens of my output chunks,
Help me how can i make this possible.
I think you should change approach, and fully use basic I/O methods. I tried to encapsulate logic in a small class, that produces a triple with id, msecs and a list of subtitles (if I'm not wrong, you can have more than a line). Then I leaved the remainder externally. Chunker is a class that reads a triple (class Three) from file, so that you can manage it and write it somewhere.
This is just a "quick&dirty" idea that you can refine, but it should work.
package org.norsam.stackoverflow;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class Chunker
{
BufferedReader r;
int chunk = 0;
File dir;
public Chunker(File dir, String filename) throws IOException
{
File f = new File(dir, filename);
this.dir = dir;
this.r = new BufferedReader(new FileReader(f));
}
public Three readThree() throws IOException
{
Integer id = Integer.parseInt(r.readLine());
String msecs = r.readLine();
String s = null;
List<String> srt = new ArrayList<>();
while (!(s = r.readLine().trim()).isEmpty()) {
srt.add(s);
}
return new Three(id, msecs, srt);
}
class Three
{
Integer id;
String msecs;
List<String> srts;
Three(Integer id, String msecs, List<String> srts)
{
this.id = id;
this.msecs = msecs;
this.srts = srts;
}
Three doSomething() {
// here you can do something with your data,
// e.g. split msecs on "-->" and check times
return this;
}
void write(BufferedWriter r) throws IOException
{
r.write(id);
r.newLine();
r.write(msecs);
r.newLine();
for (String s : srts) {
r.write(s);
r.newLine();
}
r.newLine();
}
}
public static void main(String[] args) throws IOException
{
String baseDir = "/dir/where/resides/srt";
String filename = "filename.srt";
int elemPerChunk = 50;
int fileNum = 0;
File dir = new File(baseDir);
Chunker chunker = new Chunker(dir, filename);
boolean completed = false;
while (!completed) {
int srtCount = 0;
File f = new File(baseDir, "ch." + (fileNum++) + "." + filename);
BufferedWriter w = new BufferedWriter(new FileWriter(f));
try {
while (srtCount++ < elemPerChunk) {
chunker.readThree().doSomething().write(w);
}
} catch (NullPointerException e) {
completed = true;
}
w.close();
}
}
}
I want to read a CSV file for a number of elements that can either be metal or non-metal and each line in the CSV file can have multiple elements. If it has multiple elements, all rows of the file will have that amount of elements. A valid line will look like:
<symbol,name,atomNum,mass,other/><symbol,name,atomNum,mass,other/>
where other is a character if its a nonmetal and double if its a metal. This is what I have done so far and am not sure how to read in multiple element objects on the line
public static void readValues(String fileName)
{
if (!constructed)
{
FileInputStream fileStrm = null;
InputStreamReader rdr;
BufferedReader bufRdr;
String line;
int lineNum;
try
{
fileStrm = new FileInputStream(fileName);
rdr = new InputStreamReader(fileStrm);
bufRdr = new BufferedReader(rdr);
lineNum = 0;
line = bufRdr.readLine();
while(line != null)
{
lineNum++;
elements[lineNum - 1] = processElements(line);
line = bufRdr.readLine();
System.out.println(elements);
}
fileStrm.close();
}
catch(IOException e)
{
if(fileStrm != null)
{
try
{
fileStrm.close();
constructed = true;
}
catch (IOException ex2)
{
}
}
System.out.print("error in file processing: " + e.getMessage());
}
}
}
private static Element processElements(String line)
{
char chr;
Element element;
String[] lineArray = line.split(",");
if(lineArray[4] == chr)
{
element = new NonMetal();
elements.setState(lineArray[4]);
}
else
{
element = new Metal();
element.setConduct(Double.parseDouble(lineArray[4]));
}
element.setSymbol(lineArray[0]);
element.setName(lineArray[1]);
element.setAtomNum(Integer.parseInt(lineArray[2]));
element.setMass(Double.parseDouble(lineArray[3]));
return elements;
}
I have a super element class and two subclasses, metal and nonmetal, each containing the standard methods for a class
You could use a regex to identify a group between < and />, while processing the line.
<(\w+),(\w+),(\w+),(\w+),(\w+)\/>
https://regex101.com/r/bKnYJZ/1/
String line = "<symbol,name,atomNum,mass,other/><symbol,name,atomNum,mass,other/>";
String regex = "<(\\w+),(\\w+),(\\w+),(\\w+),(\\w+)\\/>";
Matcher matcher = Pattern.compile(regex)
.matcher(line);
while (matcher.find()) {
System.out.println(matcher.group(1));
System.out.println(matcher.group(2));
System.out.println(matcher.group(3));
System.out.println(matcher.group(4));
System.out.println(matcher.group(5));
}
You could put this code into your processElements method to identify each element between < />
Aside of your problem, I suggest the use of try-resource-close for an easier and shorter resource handling.
try(FileInputStream fileStrm = new FileInputStream(fileName);
InputStreamReader rdr = new InputStreamReader(fileStrm);
BufferedReader bufRdr = new BufferedReader(rdr))
{
// here your code and no need to take care of resource closing...
}
catch(IOException e)
{
System.out.print("error in file processing: " + e.getMessage());
}
This program is meant to see two files located in a particular folder and then merge those two files and create a third file which is does. From the third merged file it is then searching for a keyword such as "test", once it finds that key word it prints out the location and the line of the keyword which is what is somewhat doing. What is happening is when I run the program it stops after the finds the keyword the first time in a line but it will not continue to search that line. So if there is multiple keyword 'test' in the line it will only find the first one and spit back the position and line. I want it to print both or multiple keywords. I think it is because of the IndexOf logic which is causing the issue.
import com.sun.deploy.util.StringUtils;
import java.io.*;
import java.lang.*;
import java.util.Scanner;
public class Concatenate {
public static void main(String[] args) {
String sourceFile1Path = "C:/Users/me/Desktop/test1.txt";
String sourceFile2Path = "C:/Users/me/Desktop/test2.txt";
String mergedFilePath = "C:/Users/me/Desktop/merged.txt";
File[] files = new File[2];
files[0] = new File(sourceFile1Path);
files[1] = new File(sourceFile2Path);
File mergedFile = new File(mergedFilePath);
mergeFiles(files, mergedFile);
stringSearch(args);
}
private static void mergeFiles(File[] files, File mergedFile) {
FileWriter fstream = null;
BufferedWriter out = null;
try {
fstream = new FileWriter(mergedFile, true);
out = new BufferedWriter(fstream);
} catch (IOException e1) {
e1.printStackTrace();
}
for (File f : files) {
System.out.println("merging: " + f.getName());
FileInputStream fis;
try {
fis = new FileInputStream(f);
BufferedReader in = new BufferedReader(new InputStreamReader(fis));
String aLine;
while ((aLine = in.readLine()) != null) {
out.write(aLine);
out.newLine();
}
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private static void stringSearch(String args[]) {
try {
String stringSearch = "test";
BufferedReader bf = new BufferedReader(new FileReader("C:/Users/me/Desktop/merged.txt"));
int linecount = 0;
String line;
System.out.println("Searching for " + stringSearch + " in file");
while (( line = bf.readLine()) != null){
linecount++;
int indexfound = line.indexOf(stringSearch);
if (indexfound > -1) {
System.out.println(stringSearch + " was found at position " + indexfound + " on line " + linecount);
System.out.println(line);
}
}
bf.close();
}
catch (IOException e) {
System.out.println("IO Error Occurred: " + e.toString());
}
}
}
It's because you are searching for the word once per line in your while loop. Each iteration of the loop takes you to the next line of the file because you are calling bf.readLine(). Try something like the following. You may have to tweak it but this should get you close.
while (( line = bf.readLine()) != null){
linecount++;
int indexfound = line.indexOf(stringSearch);
while(indexfound > -1)
{
System.out.println(stringSearch + " was found at position " + indexfound + " on line " + linecount);
System.out.println(line);
indexfound = line.indexOf(stringSearch, indexfound);
}
}
I got this far, but it seems that buffer won't take arrays, because first I had it this way
while ((strLine = br.readLine()) != null)
{
// Print the content on the console
// System.out.println (strLine);
String Record = strLine;
String delims = "[,]";
String[] LineItem = Record.split(delims);
//for (int i = 0; i < LineItem.length; i++)
for (int i = 0; i == 7; i++)
{
System.out.print(LineItem[i]);
}
now I leave at this, because it's reading but not taking out commas.
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;
public class mainPro1test {
public static void main(String[] args) {
File file = new File("test.txt");
StringBuffer contents = new StringBuffer();
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader("C:\\2010_Transactions.txt"));
String text = null;
// repeat until all lines is read
while ((text = reader.readLine()) != null) {
String Record = text;
String delims = "[,]";
String[] LineItem = Record.split(delims);
contents.append(text)
.append(System.getProperty(
"line.separator"));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
// show file contents here
System.out.println(contents.toString());
}
}
of how it should look like
input
Sell,400,IWM ,7/6/2010,62.481125,24988.02,4.43
Sell,400,IWM ,7/6/2010,62.51,24999.57,4.43
output
Sell 400 IWM 7/6/2010 62.481125 24988.02 4.43
Sell 400 IWM 7/6/2010 62.51 24999.57 4.43
If you only want to remove commas from a String, you can use String.replaceAll(",","");
If you want to replace them by spaces, use String.replaceAll(","," "):
while ((text = reader.readLine()) != null) {
contents.append(text.replaceAll(","," ");
}
Also in your code you seem to split the input, but don't use the result of this operation.
Easier is to define a new InputStream that just removes the commas...
class CommaRemovingStream extends InputStream {
private final InputStream underlyingStream;
// Constructor
#Override public int read() throws IOException {
int next;
while (true) {
next = underlyingStream.read();
if (next != ',') {
return next;
}
}
}
}
Now you can read the file without commas:
InputStream noCommasStream = new CommaRemovingStream(new FileInputStream(file));