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how to copy only a part of .CSV based on first column elements with java

copy part like this(from date to date) I am trying to copy only a part of .CSV file based on the first column (Start Date and Time) data looks like (2019-01-28 10:22:00 AM) but the user have to put it like this (2019/01/28 10:22:00)
this is for windows, java opencsv , this is what I found but dont do what I need exaclty :
like this:
int startLine = get value1 from column csv ;
int endLine = get value2 from column csv;
public static void showLines(String fileName, int startLine, int endLine) throws IOException {
String line = null;
int currentLineNo = 1;
// int startLine = 20056;//40930;
// int currentLineNo = 0;
File currentDirectory = new File(new File(".").getAbsolutePath());
String fromPath = currentDirectory.getCanonicalPath() + "\\Target\\part.csv";
PrintWriter pw = null;
pw = new PrintWriter(new FileOutputStream(fromPath), true);
//pw.close();
BufferedReader in = null;
try {
in = new BufferedReader (new FileReader(fileName));
//read to startLine
while(currentLineNo<startLine) {
if (in.readLine()==null) {
// oops, early end of file
throw new IOException("File too small");
}
currentLineNo++;
}
//read until endLine
while(currentLineNo<=endLine) {
line = in.readLine();
if (line==null) {
// here, we'll forgive a short file
// note finally still cleans up
return;
}
System.out.println(line);
currentLineNo++;
pw.println(line);
}
} catch (IOException ex) {
System.out.println("Problem reading file.\n" + ex.getMessage());
}finally {
try { if (in!=null) in.close();
pw.close();
} catch(IOException ignore) {}
}
}
public static void main(String[] args) throws FileNotFoundException {
int startLine = 17 ;
int endLine = 2222;
File currentDirectory = new File(new File(".").getAbsolutePath());
try {
showLines(currentDirectory.getCanonicalPath() + "\\Sources\\concat.csv", startLine, endLine);
} catch (IOException e) {
e.printStackTrace();
}
// pw.println();
}

Common CSV format uses a comma as a delimiter, with quotations used to escape any column entry that uses them within the data. Assuming that your column one data is consistent with the format you posted, and that I wouldn't have to bother with quotations marks therefor, you could read the columns as:
public static void main(String[] args) {
//This is the path to the file you are writing to
String targetPath = "";
//This is the path to the file you are reading from
String inputFilePath = "";
String line = null;
ArrayList<String> lines = new ArrayList<String>();
boolean add = false;
String startLine = "2019/01/28 10:22:00";
String endLine = "2019/01/28 10:30:00";
String addFlagSplit[] = startLine.replace("/", "-").split(" ");
String addFlag = addFlagSplit[0] + " " + addFlagSplit[1];
String endFlagSplit[] = endLine.replace("/", "-").split(" ");
String endFlag = endFlagSplit[0] + " " + endFlagSplit[1];
try(PrintWriter pw = new PrintWriter(new FileOutputStream(targetPath), true)){
try (BufferedReader input = new BufferedReader(new FileReader(inputFilePath))){
while((line = input.readLine()) != null) {
String date = line.split(",")[0];
if(date.contains(addFlag)) {
add = true;
}else if(date.contains(endFlag)) {
break;
}
if(add) {
lines.add(line);
}
}
}
for(String currentLine : lines) {
pw.append(currentLine + "\n");
}
}catch(FileNotFoundException e) {
e.printStackTrace();
}catch(IOException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws IOException {
File currentDirectory = new File(new File(".").getAbsolutePath());
String targetPath = currentDirectory.getCanonicalPath() + "\\Target\\part.csv";
String inputFilePath = currentDirectory.getCanonicalPath() + "\\Sources\\concat.csv";
String line = null;
ArrayList<String> lines = new ArrayList<String>();
boolean add = false;
String startLine = "2019/01/28 10:22:00";
String endLine = "2019/04/06 10:30:00";
try(PrintWriter pw = new PrintWriter(new FileOutputStream(targetPath), true)){
try (BufferedReader input = new BufferedReader(new FileReader(inputFilePath))){
while((line = input.readLine()) != null) {
String date = line.split(",")[0];
if(date.contains(startLine)) {
add = true;
}else if(date.contains(endLine)) {
break;
}
if(add) {
lines.add(line);
}
}
}
for(String currentLine : lines) {
pw.append(currentLine + "\n");
}
}catch(FileNotFoundException e) {
e.printStackTrace();
}catch(IOException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}

Debugging File Search / Merge Code

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);
}
}

Read file from a specific to a next specific line in java

I have to read a data look likes:
trace 1:
data
trace 2:
data
trace 3:
data
and so on upto last trace of file,where data is two column. I want to add the data for every trace to XYSeries. How to do that? i have done something but it reads all the data. how to split when it encounters next trace?
public static void main(String[] args) {
String line;
BufferedReader in = null;
String temp [];
try {
in = new BufferedReader (new FileReader("data.txt"));
//read until endLine
while(((line = in.readLine()) != null)) {
if (!line.contains("trace")) {
//skipping the line that start with trace
temp=(line.trim().split("[\\s]"));
//YSeries series1 = new XYSeries("test");
//series1.add(Double.parseDouble(temp[0]),Double.parseDouble(temp[1]))
}
}
} catch (IOException ex) {
System.out.println("Problem reading file.\n" + ex.getMessage());
} finally {
try { if (in!=null) in.close(); } catch(IOException ignore) {}
}
}

one way is to use a counter:
String line;
String XY="";
Integer counter=0;
List<String> XYSeries =new ArrayList<String>();
BufferedReader br = new BufferedReader(new FileReader(file));
while ((line = br.readLine()) != null) {
if(counter%2==0){
XY=line;
}
else {
XY=XY+line;
}
XYSeries.add(XY);
counter++;
}
br.close();

You could initialize a new XYSeries every time a line containing trace is read. This way, the current one is added to a list a series and another series is created for the next one.
try {
in = new BufferedReader (new FileReader("data.txt"));
//read until endLine
List<YSeries> seriesList = new ArrayList<>();
YSeries currentSeries = null;
while(((line = in.readLine()) != null)) {
if (!line.contains("trace")) {
//skipping the line that start with trace
temp=(line.trim().split("[\\s]"));
//no NullPointerException should be thrown because the file starts with a trace line but you may want to add a check, just in case
currentSeries.add(Double.parseDouble(temp[0]),Double.parseDouble(temp[1]));
} else {
//this is the start of a new trace series
if (currentSeries != null) {
seriesList.add(currentSeries);
}
currentSeries = new XYSeries(line);
}
}
} catch (IOException ex) {
System.out.println("Problem reading file.\n" + ex.getMessage());
} finally {
try { if (in!=null) in.close(); } catch(IOException ignore) {}
}

Save/Read File in android

I want to save to a file in android , Some of my arrayList that will be deleted after that.I already have two methods to write/read from android file here but the problem is I want the two methods do that:
the first method must save the element of arraylist then if I call it again it will not write the new element in the same line but write it in another line
The second must read a line (for example I give to the method which line and it returns what the lines contains)
The file looks like that :
firstelem
secondelem
thridelem
anotherelem
another ..
is this possible to do in android java?
PS: I don't need database.
Update
This is My methods :
private void writeToFile(String data) {
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(openFileOutput("config.txt", Context.MODE_PRIVATE));
outputStreamWriter.write(data);
outputStreamWriter.close();
}
catch (IOException e) {
Log.e("Exception", "File write failed: " + e.toString());
}
}
private String readFromFile() {
String ret = "";
try {
InputStream inputStream = openFileInput("config.txt");
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String receiveString = "";
StringBuilder stringBuilder = new StringBuilder();
while ( (receiveString = bufferedReader.readLine()) != null ) {
stringBuilder.append(receiveString);
// stringBuilder.append("\\n");
}
inputStream.close();
ret = stringBuilder.toString();
}
}
catch (FileNotFoundException e) {
Log.e("login activity", "File not found: " + e.toString());
} catch (IOException e) {
Log.e("login activity", "Can not read file: " + e.toString());
}
return ret;
}

Using the save method you linked to you can create the text to save with a StringBuilder:
public String makeArrayListFlatfileString(List<List<String>> listOfLists)
{
StringBuilder sb = new StringBuilder();
if (!listOfLists.isEmpty()) {
// this assumes all lists are the same length
int listLengths = listOfLists.get(0).size();
for (int i=0; i<listLengths; i++)
{
for (List<String> list : listOfLists)
{
sb.append(list.get(i)).append("\n");
}
sb.append("\n"); // blank line after column grouping
}
}
return sb.toString();
}
To parse the contents from that same file (again assuming equal length lists and a String input):
public List<List<String>> getListOfListsFromFlatfile(String data)
{
// split into lines
String[] lines = data.split("\\n");
// first find out how many Lists we'll need
int numberOfLists = 0;
for (String line : lines){
if (line.trim().equals(""))
{
// blank line means new column grouping so stop counting
break;
}
else
{
numberOfLists++;
}
}
// make enough empty lists to hold the info:
List<List<String>> listOfLists = new ArrayList<List<String>>();
for (int i=0; i<numberOfLists; i++)
{
listOfLists.add(new ArrayList<String>());
}
// keep track of which list we should be adding to, and populate the lists
int listTracker = 0;
for (String line : lines)
{
if (line.trim().equals(""))
{
// new block so add next item to the first list again
listTracker = 0;
continue;
}
else
{
listOfLists.get(listTracker).add(line);
listTracker++;
}
}
return listOfLists;
}

For writing, just as Illegal Argument states - append '\n':
void writeToFileWithNewLine(String data) {
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(openFileOutput("config.txt", Context.MODE_PRIVATE));
outputStreamWriter.write(data + "\n");
outputStreamWriter.close();
}
catch (IOException e) { /* handle exception */ }
}
For reading (just the idea, in practice you should read the file only once):
String readLine(final int lineNo) {
InputStream in = new FileInputStream("file.txt");
ArrayList<String> lines = new ArrayList<String>();
try {
InputStreamReader inReader = new InputStreamReader(in);
BufferedReader reader = new BufferedReader(inReader);
String line;
do {
line = reader.readLine();
lines.add(line);
} while(line != null);
} catch (Exception e) { /* handle exceptions */ }
finally {
in.close();
}
if(lineNo < lines.size() && lineNo >= 0) {
return lines.get(lineNo);
} else {
throw new IndexOutOfBoundsException();
}
}

Appending a text file with a 2D array

I have a method to store the input of a 2D array in a .txt file. However, even with the true put on the end of FileWriter fw = new FileWriter("CBB.dat");, something that usually allows for appending in past projects, the file still only receives one entry before writing over it with the next entry. How would this be fixed?
public void Save(String[][] EntryList)
{
try
{
File file = new File("CBB.dat");
// if file doesnt exists, then create it
if (!file.exists())
{
file.createNewFile();
}
if (EntryList[0][0] != null)
{
DataOutputStream outstream;
outstream = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(file)));
for (int row = 0; row < EntryList.length; row++)
{
for (int col = 0; col < EntryList[row].length; col++)
{
if (EntryList[row][col] != null) outstream.writeUTF(EntryList[row][col]);
}
outstream.close();
}
}
else System.out.print("Something is wrong");
} catch (IOException e)
{
e.printStackTrace();
}
}

Use a CharSequence instead of a String[][] (or you could also use variable arity parameters):
public static void save(CharSequence entryList)
{
BufferedReader read;
BufferedWriter write;
File file = new File("CBB.dat");
if (!file.exists())
{
try
{
file.createNewFile();
} catch (Exception e)
{
e.printStackTrace();
}
}
try
{
read = new BufferedReader(new FileReader(file));
String complete = "";
String line = null;
while ((line = read.readLine()) != null)
{
complete += line + "\n";
}
read.close();
write = new BufferedWriter(new FileWriter(file));
write.append(complete);
write.append(entryList);
write.flush();
write.close();
} catch (Exception e)
{
e.printStackTrace();
}
}