We Keep Coding

Get single line and multiple line values from text file

I use following Java code to get specific values from a text file, which contains key-value pairs in different order.
if(nfo_file.exists() && !nfo_file.isDirectory()) {
Scanner scanner = new Scanner(nfo_file);
Map<String, String> values = new HashMap<>();
String line, key = null, value = null;
while (scanner.hasNextLine()) {
line = scanner.nextLine();
if (line.contains(":")) {
if (key != null) {
values.put(key, value.trim());
}
int indexOfColon = line.indexOf(":");
key = line.substring(0, indexOfColon);
value = line.substring(indexOfColon + 1);
} else {
value += " " + line;
}
}
for (Map.Entry<String, String> entry : values.entrySet()) {
if (entry.getKey().startsWith("Description")) {
nfodata[0] = entry.getValue();
}
Input text file example:
Num: 10101
Name: File_8
Description: qwertz qwertz
qwertz (qwertz) ztrewq?
Neque porro quisquam est qui
Quantity: 2
It doesn't work in some cases, it doesn't read one liners and sometimes read only first line of a multiline value.

It looks like your code will not add the last key-value pair to the Map.
Try:
while (scanner.hasNextLine()) {
line = scanner.nextLine();
if (line.contains(":")) {
if (key != null) {
values.put(key, value.trim());
key = null;
value = null;
}
int indexOfColon = line.indexOf(":");
key = line.substring(0, indexOfColon);
value = line.substring(indexOfColon + 1);
} else {
value += " " + line;
}
}
if (key != null) {
values.put (key, value.trim());
}

How to Iterate Twice over Map values in Java

I know there are other solutions out there but nothing is working for me.
Question: In my main method, I group together IDs by rating and make the rating the key and the rest of the info the value as a List. When I create the hashmap and put in the lists I can accurately print the contents of the hashmap. However, once I pass the map the evaluate method, the values are lost and I cannot iterate in the same way that I did in the main method, even though the logic is the same. I am not experienced with the Map class in java. Can somebody please help me figure out why when I pass the Map to my evaluate method that I can no longer iterate the Map?
import java.io.*;
import java.util.*;
public class Evaluate {
public static double grandTotal;
public static void main(String[] args) throws Exception {
FileInputStream fs = new FileInputStream("testInput.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fs));
FileInputStream fs2 = new FileInputStream("testTest.txt");
BufferedReader br2 = new BufferedReader(new InputStreamReader(fs2));
String line;
String line2;
String[] bloop;
String bleep;
String flooper;
String splitter;
String[] splitInput;
List<String> oneStarList= new ArrayList<String>();
List<String> twoStarList= new ArrayList<String>();
List<String> threeStarList= new ArrayList<String>();
List<String> fourStarList= new ArrayList<String>();
List<String> fiveStarList= new ArrayList<String>();
List<String> values2 = new ArrayList<String>();
try {
while ((line=br.readLine()) != null) {
bloop = new String[10];
bloop = line.split("\\s+");
bleep = bloop[1].toString();
flooper = (bloop[0]+" "+bloop[2]+" "+bloop[3]+" "+bloop[4]);
if (bleep.equals("1")){
oneStarList.add(flooper);
}
else if (bleep.equals("2")){
twoStarList.add(flooper);
}
else if (bleep.equals("3")){
threeStarList.add(flooper);
}
else if (bleep.equals("4")){
fourStarList.add(flooper);
}
else if (bleep.equals("5")){
fiveStarList.add(flooper);
}
grandTotal+=(Double.parseDouble(bloop[2]));
}
}
catch (Exception e){
}
Map<String,List<String>> hmap = new HashMap<String,List<String>>();
hmap.put("1",oneStarList);
hmap.put("2", twoStarList);
hmap.put("3", threeStarList);
hmap.put("4", fourStarList);
hmap.put("5", fiveStarList);
while ((line2=br2.readLine()) != null) {
splitInput = new String[5];
splitInput = line2.split("\\s+");
evaluate(splitInput[0],splitInput[1],hmap);
}
br.close();
br2.close();
}
public static void evaluate(String movID, String usrID, Map<String,List<String>> hash) throws Exception{
FileWriter fw = new FileWriter("outputTest.txt");
BufferedWriter bwr = new BufferedWriter(fw);
List<String> values = new ArrayList<String>();
List<String> outputList = new ArrayList<String>();
String[] floop;
String fleep;
int movIDtotal=0;
int usrIDtotal=0;
int totalValues=0;
double pmovIDStar=0;
double pusrIDStar=0;
double pmovID=0;
double pusrID=0;
double numID=0;
double keyTotalProb=0;
String keyOutputStr;
String keyHold;
final Set<Map.Entry<String,List<String>>> entries = hash.entrySet();
for (String key : hash.keySet()){
values = hash.get(key);
System.out.println(key + ":");
for (int i=0;i<values.size();i++){
System.out.println(values.get(i));
floop = new String[5];
fleep = values.get(i);
floop = fleep.split("\\s+");
if (movID.equals(floop[0])){
movIDtotal++;
totalValues++;
}
if (usrID.equals(floop[0])){
usrIDtotal++;
totalValues++;
}
}
values.clear();
}
for (Map.Entry<String, List<String>> entry: entries){
values= entry.getValue();
keyHold = entry.getKey();
for (int j=0;j<values.size();j++){
floop = new String[5];
fleep = values.get(j);
floop = fleep.split("\\s+");
if (movID.equals(floop[0])){
pmovIDStar = Double.parseDouble(floop[3]);
numID = Double.parseDouble(floop[1]);
pmovID = (numID/movIDtotal);
}
if (usrID.equals(floop[0])){
pusrIDStar = Double.parseDouble(floop[3]);
numID = Double.parseDouble(floop[1]);
pusrID = (numID/usrIDtotal);
}
}
keyTotalProb = ((totalValues/grandTotal)*(pmovIDStar)*(pusrIDStar))/(pusrID*pmovID);
keyOutputStr = Double.toString(keyTotalProb);
outputList.add(keyHold);
outputList.add(keyOutputStr);
values.clear();
}
double max = Double.MIN_VALUE;
for (int m=0;m<outputList.size();m+=2){
double coolguy = Double.parseDouble(outputList.get(m+1));
int index = 0;
if(coolguy>max){
max = coolguy;
index = m;
}
try {
bwr.write(String.format("%-1s %-1s %-1s%n", movID,usrID,outputList.get(index)));
bwr.close();
fw.close();
}
catch(Exception e) {
}
}
}
}
Backup info: I'm trying to build a java program that essentially performs the final stage of the Naive Bayes algorithm to predict user ratings (1-5) for movies. I have used MapReduce to train data and now I have an input file where each line contains a string containing information in this order without the commas (movie or user id,rating , number of times rating and ID occur together in total, number of times ID occurs in total, probability that ID and rating occur together out of all ratings for ID). Essentially this is the classification stage.

never suppress excetions. especially when you do coding/debugging.
catch (Exception e){ } is very bad practice
When you do:
final Set<Map.Entry<String,List<String>>> entries = hash.entrySet();
it does not copy hash.entrySet to entries. It creates another reference to it.
same is for values= entry.getValue();
then what do you expect after your first loop (and others too)?
when you do:
values.clear();
your values gone from the lists which are in hash and since entries is just a reference to hash.entrySet() you have what you've done - empty lists.

HashMaps, HashSets, and FileReader and FileWriter?

This code is to find the TF-IDF of words in 40 text files in a folder called docs, whenever I use this program I keep on getting null pointer exceptions. I believe it is coming from the computeTermFrequencies method. I want it to print the top 5 TF-IDF words from each file.
Any help would be greatly appreciated! Thank you!
import java.util.*;
import java.io.*;
public class KeywordExtractor {
public static void main(String[] args) {
String dir = args[0]; // name of directory with input files
HashMap<String, Integer> dfs;
dfs = readDocumentFrequencies("freqs.txt");
for(int i = 1; i <= 40; i++){
String name = dir + "/" + i + ".txt";
HashMap<String,Integer> tfs = computeTermFrequencies(name);
HashMap<String,Double> tfidf = computeTFIDF(tfs,dfs,40);
System.out.println(i + ".txt");
printTopKeywords(tfidf,5);
System.out.println();
}
}
//method to that takes string as input and returns hashmap with amount of times
//each word appears in the file
public static HashMap<String, Integer> computeTermFrequencies(String filename) {
HashMap<String, Integer> hm2 = new HashMap<String, Integer>();
try{
FileReader fr = new FileReader(filename);
BufferedReader br = new BufferedReader(fr);
String line = "";
line = normalize(line);
//for(String line = br.readLine(); line != null; line = br.readLine()){
while((line=br.readLine())!=null){
String[] words = line.split(" ");
for(int i = 0; i < words.length; i++){
String word = words[i];
if(hm2.containsKey(word)){
int x = hm2.get(word);
x++;
hm2.put(word,x);
}else{
hm2.put(word,1);
}
} //end for
}//end for
}catch(IOException e){
//error
}
return hm2;
}
//method to read frequency file created in another class, it returns a hashMap
public static HashMap<String, Integer> readDocumentFrequencies(String filename){
HashMap<String, Integer> hm = new HashMap<String, Integer>();
//try block
try{
//read file
FileReader fr = new FileReader(filename);
BufferedReader br = new BufferedReader(fr);
//for loop to loop through and take words and put in hashmap
for(String line = br.readLine(); line != null; line = br.readLine()){
String[] a = line.split(" ");
String word = a[0];
int number = Integer.parseInt(a[1]);
//put word in hashmap with the frequency of the word
hm.put(word,number);
if(hm.get(word)==null){
System.out.println("sads");
}
}//end for
}
catch(IOException e){
//error
}
return hm;
}
public static HashMap<String, Double> computeTFIDF(HashMap<String, Integer> tfs, HashMap<String, Integer> dfs,
double nDocs) {
HashMap<String, Double> hm3 = new HashMap<String, Double>();
for(String key:tfs.keySet()){
/*if(dfs.get(key)==null){
System.out.println(key);
}*/
double idf = Math.log(nDocs/dfs.get(key));
double tf = tfs.get(key);
hm3.put(key,tf*idf);
}
return hm3;
}
/**
* This method prints the top K keywords by TF-IDF in descending order.
*/
public static void printTopKeywords(HashMap<String, Double> tfidfs, int k) {
ValueComparator vc = new ValueComparator(tfidfs);
TreeMap<String, Double> sortedMap = new TreeMap<String, Double>(vc);
sortedMap.putAll(tfidfs);
int i = 0;
for(Map.Entry<String, Double> entry: sortedMap.entrySet()){
String key = entry.getKey();
Double value = entry.getValue();
System.out.println(key + " " + value);
i++;
if (i >= k) {
break;
}
}
}
public static String normalize(String word) {
return word.replaceAll("[^a-zA-Z ']", "").toLowerCase();
}
}
/*
* This class makes printTopKeywords work. Do not modify.
*/
class ValueComparator implements Comparator<String> {
Map<String, Double> map;
public ValueComparator(Map<String, Double> base) {
this.map = base;
}
public int compare(String a, String b) {
if (map.get(a) >= map.get(b)) {
return -1;
} else {
return 1;
} // returning 0 would merge keys
}
}

Reading file and store in vector

I'm reading from the file:
name1 wordx wordy passw1
name2 wordx wordy passw2
name3 wordx wordy passw3
name (i) wordx wordy PASSW (i)
x
x word
x words
words
x
words
At the moment I can print line by line:
Line 1: name1 wordx wordy passw1
Line 2: name2 wordx wordy passw2
I plan to have access to:
users [0] = name1
users [1] = name2
users [2] = name3
..
passws [0] = passw1
passws [1] = passw2
passws [2] = passw3
..
My code is:
public static void main(String args[]) throws FileNotFoundException, IOException {
ArrayList<String> list = new ArrayList<String>();
Scanner inFile = null;
try {
inFile = new Scanner(new File("C:\\file.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
while (inFile.hasNextLine()) {
list.add(inFile.nextLine()+",");
}
String listString = "";
for (String s : list) {
listString += s + "\t";
}
String[] parts = listString.split(",");
System.out.println("Line1: "+ parts[0]);
}
How do I get the following output:
User is name1 and password is passw1
User is name32 and password is passw32
Thanks in advance.

Something like this will do:
public static void main(String args[]) throws FileNotFoundException, IOException {
ArrayList<String> list = new ArrayList<String>();
Scanner inFile = null;
try {
inFile = new Scanner(new File("C:\\file.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
while (inFile.hasNextLine()) {
list.add(inFile.nextLine());
}
int line = 0;
String[] parts = list.get(line).split(" ");
String username = parts[0];
String pass = parts[3];
System.out.println("Line" + (line + 1) + ": " + "User is " + username +" and password is " + pass);
}
EDIT: if you want to iterate through all lines just put last lines in a loop:
for (int line = 0; line < list.size(); line++) {
String[] parts = list.get(line).split(" ");
String username = parts[0];
String pass = parts[3];
System.out.println("Line" + (line + 1) + ": " + "User is " + username +" and password is " + pass);
}

First thing to do is, to add this loop to the end of your code :
for(int i = 0; i <= parts.length(); i++){
System.out.println("parts["+i+"] :" + parts[i] );
}
that will simply show the result of the split using ,.
Then adapt your code, you may want to use another regex to split() your lines, for instance a space.
String[] parts = listString.split(" ");
for documentation about split() method check this.

If you want to get that output then this should do the trick:
public static void main(String args[]) throws FileNotFoundException, IOException {
Scanner inFile = null;
try {
inFile = new Scanner(new File("F:\\file.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Map<String, String> userAndPassMap = new LinkedHashMap<>();
while (inFile.hasNextLine()) {
String nextLine = inFile.nextLine();
String[] userAndPass = nextLine.split(" ");
userAndPassMap.put(userAndPass[0], userAndPass[1]);
}
for (Map.Entry<String, String> entry : userAndPassMap.entrySet()) {
System.out.println("User is:" + entry.getKey() + " and password is:" + entry.getValue());
}
}
By storing in a map you are linking directly each username with its password. If you need to save them into separate arrays then you can do this in the while loop instead:
List<String> users = new LinkedList<>(),passwords = new LinkedList<>();
while (inFile.hasNextLine()) {
String nextLine = inFile.nextLine();
String[] userAndPass = nextLine.split(" ");
users.add(userAndPass[0]);
passwords.add(userAndPass[1]);
}
and later transform them to arrays
users.toArray()

I recommend you use a java.util.Map, a standard API which allows you to store objects and read each one of them by a key. (In your case, string objects indexed by string keys). Example:
Let's assume this empty map:
Map<String, String> map=new HashMap<String,String>();
If you store this:
map.put("month", "january");
map.put("day", "sunday");
You can expect that map.get("month") will return "january", map.get("day") will return "sunday", and map.get(any-other-string) will return null.
Back to your case: First, you must create and populate the map:
private Map<String, String> toMap(Scanner scanner)
{
Map<String, String> map=new HashMap<String, String>();
while (scanner.hasNextLine())
{
String line=scanner.nextLine();
String[] parts=line.split(" ");
// Validation: Process only lines with 4 tokens or more:
if (parts.length>=4)
{
map.put(parts[0], parts[parts.length-1]);
}
}
return map;
}
And then, to read the map:
private void listMap(Map<String,String> map)
{
for (String name : map.keySet())
{
String pass=map.get(name);
System.out.println(...);
}
}
You must include both in your class and call them from the main method.

If you need arbitraray indexing of the read lines, use ArrayList:
First, define a javabean User:
public class User
{
private String name;
private String password;
// ... add full constructor, getters and setters.
}
And then, you must create and populate the list:
private ArrayList<User> toList(Scanner scanner)
{
List<User> list=new ArrayList<User>();
while (scanner.hasNextLine())
{
String line=scanner.nextLine();
String[] parts=line.split(" ");
// Validation: Process only lines with 4 tokens or more:
if (parts.length>=4)
{
list.add(new User(parts[0], parts[parts.length-1]));
}
}
return list;
}

inefficient looping in java

This is my csv data:
Name,Code,Price,Colour,Type,Stock
A,1001,35000,Red,Car Paint,54
B,1002,56000,Blue,House Paint,90
As you can see, my coding is inefficient.
This is because all the textfields in netbeans do not allow same variable names, I have to give different variable names to each text field (Example: code1, code2, code3, name1, name2,name3)
Can someone help me on how to loop this data so they do it four times and i dont have to repeat the coding? and to skip the process if the fields are blank.
The following is my coding:
try
{
for(int z=0; z<4;z++)
{
String code1;
code1=this.text1.getText();
System.out.println("this is the code: " + code1);
String qty;
int qty1;
qty=this.quantity1.getText();
qty1=Integer.parseInt(qty);
System.out.println("quantity: "+qty1);
String code2;
code2=this.text2.getText();
System.out.println("this is the code: " + code2);
int qty2;
qty=this.quantity2.getText();
qty2=Integer.parseInt(qty);
System.out.println("quantity: "+qty2);
String code3;
code3=this.text3.getText();
System.out.println("this is the code: " + code3);
int qty3;
qty=this.quantity2.getText();
qty3=Integer.parseInt(qty);
System.out.println("quantity: "+qty3);
String code4;
code4=this.text4.getText();
System.out.println("this is the code: " + code4);
int qty4;
qty=this.quantity2.getText();
qty4=Integer.parseInt(qty);
System.out.println("quantity: "+qty4);
int sum=0;
BufferedReader line = new BufferedReader(new FileReader(new File("C:\\Users\\Laura Sutardja\\Documents\\IB DP\\Computer Science HL\\cs\\product.txt")));
String indata;
ArrayList<String[]> dataArr = new ArrayList<>();
String[] club = new String[6];
String[] value;
while ((indata = line.readLine()) != null) {
value = indata.split(",");
dataArr.add(value);
}
for (int i = 0; i < dataArr.size(); i++) {
String[] nameData = dataArr.get(i);
if (nameData[1].equals(code1)) {
System.out.println("Found name.");
name1.setText(""+ nameData[0]);
int price;
price=Integer.parseInt(nameData[2]);
int totalprice=qty1*price;
String total=Integer.toString(totalprice);
price1.setText(total);
sum=sum+totalprice;
break;
}
}
for (int i = 0; i < dataArr.size(); i++) {
String[] nameData = dataArr.get(i);
if (nameData[1].equals(code2)) {
System.out.println("Found name.");
name2.setText(""+ nameData[0]);
int price;
price=Integer.parseInt(nameData[2]);
int totalprice=qty2*price;
String total=Integer.toString(totalprice);
price2.setText(total);
sum=sum+totalprice;
break;
}
}
for (int i = 0; i < dataArr.size(); i++) {
String[] nameData = dataArr.get(i);
if (nameData[1].equals(code3)) {
System.out.println("Found name.");
name3.setText(""+ nameData[0]);
int price;
price=Integer.parseInt(nameData[2]);
int totalprice=qty3*price;
int totalprice3=totalprice;
String total=Integer.toString(totalprice);
price3.setText(total);
sum=sum+totalprice;
break;
}
}
for (int i = 0; i < dataArr.size(); i++) {
String[] nameData = dataArr.get(i);
if (nameData[1].equals(code4)) {
System.out.println("Found name.");
name4.setText(""+ nameData[0]);
int price;
price=Integer.parseInt(nameData[2]);
int totalprice=qty4*price;
int totalprice4=totalprice;
String total=Integer.toString(totalprice);
price4.setText(total);
sum=sum+totalprice;
break;
}
}
total1.setText("Rp. "+sum);
}
}
catch ( IOException iox )
{
System.out.println("Error");
}

Why don't you use a library like http://commons.apache.org/proper/commons-csv/

Solving this problem is actually rather straight forward if you break it down into separate parts.
First you need to solve the problem of loading the data into an internal data representation that is easy to use. Just loading the file into Java is rather simple and you have already done this:
BufferedReader csvFile = new BufferedReader(new FileReader(new File(path)));
String line = "start";
int count = 0;
while((line = csvFile.readLine()) != null){
System.out.println(line);
}
csvFile.close();
The next problem is splitting the line and store it in a meaningful way - for each line.
HashMap<Integer, String> record = new HashMap<Integer, String>();
String[] raw = line.split(",");
for(int i=0;i<raw.length; i++){
record.put(i, raw[i]);
}
Now you state you only want to store records that have non-empty fields so we need to check for that:
HashMap<Integer, String> record = new HashMap<Integer, String>();
String[] raw = line.split(",");
Boolean store = true;
for(int i=0;i<raw.length; i++){
if(raw[i].equals("") || raw[i].equals(null)){
store = false;
break;
}
record.put(i, raw[i]);
}
if(store)
csvData.add(record);
Now, you can load each record of the csv file as a dictionary that you can easily use. All that remains is to save a list of these dictionaries.
ArrayList<Map<Integer, String>> csvData = new ArrayList<Map<Integer, String>>();
BufferedReader csvFile = new BufferedReader(new FileReader(new File(path)));
String line = "start";
int count = 0;
while((line = csvFile.readLine()) != null){
if(count == 0){//skip first line
count++;
continue;
}
HashMap<Integer, String> record = new HashMap<Integer, String>();
String[] raw = line.split(",");
Boolean store = true;
for(int i=0;i<raw.length; i++){
if(raw[i].equals("") || raw[i].equals(null))
{
store = false;
break;
}
record.put(i, raw[i]);
}
if(store)
csvData.add(record);
}
csvFile.close();
Full code snippet that loads in data and easily access whatever information you want:
public class Main {
public static final int NAME = 0;
public static final int CODE = 1;
public static final int PRICE = 2;
public static final int COLOR = 3;
public static final int TYPE = 4;
public static final int STOCK = 5;
public static void main(String[] args) throws IOException{
ArrayList<Map<Integer, String>> csvData = loadCSVFile("C:\\path\\to\\file\\products.txt");
//Print some of the data
System.out.println("---------------------------");
for(Map<Integer, String> record : csvData){
printInfo(record);
}
}
public static ArrayList<Map<Integer, String>> loadCSVFile(String path) throws IOException{
ArrayList<Map<Integer, String>> csvData = new ArrayList<Map<Integer, String>>();
BufferedReader csvFile = new BufferedReader(new FileReader(new File(path)));
String line = "start";
int count = 0;
while((line = csvFile.readLine()) != null){
if(count == 0){
count++;
continue;
}
HashMap<Integer, String> record = new HashMap<Integer, String>();
String[] raw = line.split(",");
Boolean store = true;
for(int i=0;i<raw.length; i++){
if(raw[i].equals("") || raw[i].equals(null))
{
store = false;
break;
}
record.put(i, raw[i]);
}
if(store)
csvData.add(record);
}
csvFile.close();
return csvData;
}
public static void printInfo(Map<Integer, String> record){
System.out.println(record.get(CODE) + " : " + record.get(TYPE));
System.out.println(record.get(NAME) + " : " + record.get(STOCK) + " : " + record.get(PRICE));
System.out.println("---------------------------");
}
}