Here is the code:
public int docLength(String filename) throws IOException {
int length = 0;
TermFreqVector t = indexReader.getTermFreqVector(0, "contents");
for (int i = 0; i < t.getTermFrequencies().length; i++) {
length += t.getTermFrequencies()[i];
}
return length;
}
public int docLength(int id) throws IOException {
int length = 0;
TermFreqVector t = indexReader.getTermFreqVector(id, "contents");
for (int i = 0; i < t.getTermFrequencies().length; i++) {
length += t.getTermFrequencies()[i];
}
return length;
}
The error is :
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
TermFreqVector cannot be resolved to a type
The method getTermFreqVector(int, String) is undefined for the type IndexReader
at BM25.docLength(BM25.java:96)
at BM25.avgDocLength(BM25.java:130)
Accessing and traversing term vectors changed significantly in 4.0. The Migration Guide is a very helpful resource on that and other changes from 3.6 to 4.0.
In this case, you'll need to access a Terms instance through a call to IndexReader.getTermVector:
int length = 0;
TermEnum terms = indexReader.getTermVector(id, "contents").iterator();
while (terms.next())
length += terms.totalTermFreq(null);
return length;
Related
Here are the codes attached below. I have done these problems in one of the FAANG companies. I am open to have a discussion on time complexity and space complexity of these codes.
Code1:
public static void main(String[] args) {
int[] arr = {4,5,6,7};
Queue<Integer> queue = new LinkedList<>();
for (int i = 0; i < arr.length; i++) {
queue.add(arr[i]);
}
System.out.println(queue);
while (queue.size() > 2) {
int first = queue.poll();
for (int i = 0; i < queue.size(); i++) {
int second = queue.poll();
queue.add(first % 10 + second % 10);
first = second;
}
}
int first = queue.poll() % 10;
int second = queue.poll() % 10;
int res = first + second;
System.out.println(res);
}
Time Complexity: ?
Space Complexity: ?
and Code 2:
public static void main(String[] args) {
String input = "aabbcaac";
HashMap<Character, Integer> map1 = new HashMap<>();
HashMap<Character, Integer> map2 = new HashMap<>();
char[] ip = input.toCharArray();
for (int i = 0; i < ip.length; i++) {
map2.put(ip[i], map2.getOrDefault(ip[i] , 0)+1);
}
System.out.println (map2);
int currVal = 0;
int result = 0;
int k = 1;
for (char str : ip) {
map2.put(str, map2.get(str) - 1);
if (map2.get(str) > 0) {
currVal += 1;
}
if(map1.get(str) == null) {
map1.put(str, 0);
}
if (map1.get(str) > 0) {
currVal -= 1;
}
map1.put(str, map1.get(str) + 1);
if (currVal > k) {
result += 1;
}
System.out.println(currVal);
}
System.out.println(result);
}
Time Complexity: ?
Space Complexity: ?
I'm currently new to TestNG using java. I'm trying to read the values from an excel using poi apache 4.0
public static void read2dRowExcelFile2(String filePath) throws IOException {
try {
FileInputStream fis = new FileInputStream(new File(filePath));
HSSFWorkbook wb = new HSSFWorkbook(fis);
HSSFSheet sheet = wb.getSheet("PerLocation");
Object[][] tableArr = new String[sheet.getLastRowNum() + 1][];
int arrNo1 = 0;
for (int i = 1; i <= sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);
int arrNo2 = 0;
for (int j = 0; j < row.getLastCellNum(); j++) {
String cellValue = row.getCell(j).getStringCellValue();
System.out.println(acellValue);
//tableArr[arrNo1][arrNo2] = cellValue;
System.out.println("test");
arrNo2++;
}
arrNo1++;
}
wb.close();
} catch (Exception e) {
e.printStackTrace();
}
}
Code above displays the values on the console. My goal is to store those values to an Object. Something like [{London, Blue},{Tokyo,Yellow},{Manila,Red}] so I can pass them to a dataProvider
If I run the code above, it displays :
London
BLue
Tokyo
Yellow
Manila
Red
But If i uncomment this line :
//tableArr[arrNo1][arrNo2] = cellValue;
The output is only :
London
03-08-19 : After I enabled stacktrace, it says : java.lang.NullPointerException
which pertains to this code :
tableArr[arrNo1][arrNo2] = cellValue;
From your code,
Object[][] tableArr = new String[sheet.getLastRowNum() + 1][];
At the time of initialization of array, your are setting size of first dimension but not the second . You need to initialize array for second dimension before you access it.
Refer below example:
public static void main(String[] args) {
//read rows size
int numOfRows = 3;
String[][] tableArr = new String[numOfRows][];
for (int row = 0; row <3; row++) {
//read columns size
int numOfColsInRow = 3;
tableArr[row]=new String[numOfColsInRow];
for (int col = 0; col < 3; col++) {
String cellValue = "cell-" + row+""+col;//read cell value
tableArr[row][col] = cellValue;
}
}
for(String[] row: tableArr) {
System.out.println(Arrays.toString(row));
}
}
Running above code with generate expected output:
[cell-00, cell-01, cell-02]
[cell-10, cell-11, cell-12]
[cell-20, cell-21, cell-22]
To reproduce your problem you can try commenting line which initialize array for second dimension in the code and you will see Exception in thread "main" java.lang.NullPointerException
.
//tableArr[row]=new String[numOfColsInRow];
To avoid all such issues you also can check if any exiting TestNG data-provider extension satisfies your need.
I am required to find the largest string in the ArrayList, and the print it. My code is not currently working though.
public class Solution {
private static List<String> strings;
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
strings = new ArrayList<String>();
for (int i = 0; i < 5; i++) {
String n = reader.readLine();
strings.add(n);
}
String largestString = strings.get(0);
for (int i = 0; i < strings.size(); i++) {
if (strings.get(i).length() > largestString.length()) {
largestString = strings.get(i);
System.out.println(largestString);
}
}
}
}
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
String value = null;
int length = 0;
for (int i = 0; i < 5; i++) {
String n = reader.nextLine();
if (n != null && n.length() > length) {
length = n.length();
value = n;
}
}
System.out.println("Largest String : " + value + " of length : " + length);
}
I'm trying to create a basic function that calls on a method that creates the 2D ArrayList that will be used further in the main program to do things like calculate the row and column sums as well as print out the triangle.
However, after it runs the ArrayList returns null. What's going on?
Thanks,
public class Trib
{
private ArrayList<ArrayList<Integer>> triangle;
private int Asize;
public Trib (int size)
{
// convert the argument to type 'int' to be used in the program
Asize = size;
// create an ArrayList of ArrayLists, it will have 'size' number ArrayLists contained within
ArrayList<ArrayList<Integer>> triangle = new ArrayList<ArrayList<Integer>>(size);
// create the inner ArrayLists
for (int i = 0; i < size; i++)
{
// add to index 'i' of our ArrayList a new ArrayList of size (i+1)
triangle.add(new ArrayList<Integer>(i+1));
for (int j = 0; j <= i; j++)
{
if (j==0 || j == i)
{
triangle.get(i).add(1);
}
else
triangle.get(i).add(triangle.get(i-1).get(j-1)+triangle.get(i-1).get(j));
System.out.print(triangle.get(i).get(j) + " ");
}
System.out.println();
}
triangle.clone();
}
public void printTriangle()
{
System.out.print(triangle.get(1).get(1));
/*for (int i = 0; i < Asize; i++)
{
for (int j = 0; j <= i; j++)
{
System.out.print(triangle.get(1).get(1) + " ");
}
System.out.println();
}*/
}
/*public Trib()
{
this(5);
}*/
/*public int Psize()
{
return triangle.size();
}
public ArrayList<Integer> sumRows()
{
ArrayList<Integer> row_sum = new ArrayList<Integer>(Asize);
for (int i = 0; i < Asize; i++)
{
for (int j = 0; j < i; j++)
{
row_sum.add(triangle.get(i).get(j));
}
}
return row_sum;
}
public ArrayList<Integer> sumCols()
{
ArrayList<Integer> col_sum = new ArrayList<Integer>(Asize);
for (int i = 0; i < Asize; i++)
{
for (int j = 0; j < i; j++)
{
col_sum.add(triangle.get(i).get(i));
}
}
return col_sum;
}*/
public static void main(String[] args)
{
if(args.length < 1)
{
System.err.println("Sorry, this program needs an integer argument.");
System.exit(1);
}
Trib pt = new Trib(Integer.parseInt(args[0]));
pt.printTriangle();
//ArrayList<Object> sum_rows = new ArrayList<Object>(pt.Psize());
// sum_rows.add;
System.out.println("\nHere are the sum of rows:");
//for (int i = 0; i < pt.Psize(); i++)
//System.out.println(sum_rows.get(i));
//ArrayList<Integer> sum_cols = new ArrayList<Integer>(pt.Psize());
System.out.println("\nHere are the sum of columns:");
//for (int i = 0; i < pt.Psize(); i++)
//System.out.printf("%-5d", sum_cols.get(i));
}
}
Watch out what's what you are doing: Notice that you have TWO variables named "triangle": The first one is an instance variable and the second is a local variable, which is the only one you have initialized.
My suggestion to avoid this common mistake is to pre-pend "this." to any use of what you intend must be an instance variable. And, if in doubt, if you use a development environment as Eclipse, press CTRL and click on your variable to navigate to the point where it is declared.
This is a homework, I would appreciate any kind of answer.
Im trying to figure out why i keep getting a NullPointerException when i call the equals method. I have instantiated the object if im not mistaken, but it still doesn't work.
Exception in thread "main" 8
java.lang.NullPointerException
at labbfyra.TextBuilder.equals(TextBuilder.java:69)
at labbfyra.SkapaOrd.main(SkapaOrd.java:17)
Is this the stacktrace?
public class TextBuilder {
private static class Node{
public char inChar;
public Node next;
public Node(char c, Node nästa){
inChar = c;
next = nästa;
}
}
private Node first = null;
private Node last = null;
public TextBuilder(){
first = null;
last = null;
}
public void append(String s){
int x = s.length();
for(int i=0;i<x;i++){
Node n = new Node(s.charAt(i),null);
if(first ==null){
first = n;
last = n;
}else{
last.next = n;
last = n;
}
}
}
public int ShowSize(){
int counter = 0;
Node n = first;
while(n!=null){
counter++;
n=n.next;
}
return counter;
}
public boolean equals(String s){
boolean eq = false;
int counter = 0;
char[] cArray = s.toCharArray();
char[] cArrayComp = new char[10];
Node n = first;
cArrayComp[counter] = n.inChar;
while(n!=null){
counter++;
n=n.next;
cArrayComp[counter] = n.inChar; //THIS IS LINE 69
}
if(cArrayComp==cArray){
eq = true;
}
else{
eq=false;
}
return eq;
}
}
In your while loop, you check that n is not null, but then you assign n.next to n just before accessing n. The problem is that you do not ensure that the assigned value (n.next) is not null.
At a quick glance, looks like the counter variable in your while loop is going past the 10 you set your cArrayComp size to. Perhaps the string parameter being passed is longer than 10 chars?
public boolean equals(String s){
boolean eq = false;
int counter = 0;
char[] cArray = s.toCharArray();
char[] cArrayComp = new char[10];
Node n = first;
while(n!=null){
System.out.println(counter);
cArrayComp[counter] = n.inChar;
System.out.println(cArrayComp[counter]);
System.out.println(n.inChar);
n=n.next;
counter++;
}
if(cArrayComp==cArray){
eq = true;
}
else{
eq=false;
}
return eq;
}
This is the corrected version, i found a bug in your loop. Just check my version. Works at 100%