How do I read in a file line by line into an array without using arraylist?
I know how to do this using BufferedReader, but I am wondering how to do this using Scanner? When I used BufferedReader I noticed that there must be two exceptions to be caught which were IOException and FileNotFoundException, whereas a Scanner needs only a FileNotFoundException, why is that?
Java Code: public class practice {
public String[] array;
Scanner inputStream = null;
Scanner n = new Scanner(System.in);
public String line;
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data. Here is the base Product class that must be used to create the objects for the array.
public class Product { public String pName; public String stringName; public double price; public int quanity;
[Code]...
these continue for about 40-50 entries, they are not seperated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name seperated with spaces, then price after a comma, then quanity after the second comma.....
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product { public String pName; public String stringName; public double price; public int quanity; //Constructor public Product( String pName, double price, int quanity )
[code]....
and then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
these continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quanity after the second comma.....
I'm working on a project in which I need to read an entire block of text from a file, modify the text, and store the text into a character array. This wouldn't seem so bad, except I have to do this through the command line.
For example, in the terminal:
java program < input.txt
runs the program and uses data from input.txt.
I've considered using an input stream, but most tutorials on reading from a file involve creating a file object such as
FileInputStream fis = new FileInputStream("input.txt");
I'm not supposed to include the file name in the code. I'm not supposed to ask for the file name either.
I've used code such as
final static int MAX = 10000; public static void main(String[] args) throws IOException { // TODO code application logic here InputStreamReader stdin = new InputStreamReader(System.in); char[] cbuf = new char[MAX]; stdin.read(cbuf); String str = cbuf.toString(); System.out.println(str); }
This does store the text into an array, but I need to make adjustments to the text. Using toString prints a memory address.
storing data from an input stream into a string or an array using redirection so that I can then modify the contents of the string/array later on in the program?
I am having issues insert each line of the simple textfile into a specific varible I want it to go to. For example my text file is ordered like this
Dallas 78 F North, 15 mph dallasimage Denver 29 F South, 10 mph denverimage
and I want Dallas in city variable, 78f in temperature variable, and so on until text ends, at the moment is all goes into city variable, it all prints from there! I tried inserting it into an array but it would read all the lines previous to it in addition to reusing readline and all failed.
import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; public class Textreader { public static void main(String[] args) {
I can read the data to a monitor perfectly. But, I'm having problem reading data from an external file into an array of class objects. Here's my attempt at writing the method:
private void openFile() //This method asks the user to enter a file name(including the file extension) and then //Sets the data to an array of Product type { String fileName, storeName="", emptyLine1="", emptyLine2="", name="", productName=""; int demandRate=0; double setupCost=0.0, unitCost=0.0, inventoryCost=0, sellingPrice=0; Scanner inputStream = null;
I am reading records from a txt file and storing it into an array
import java.util.*; import java.io.*; public class PatientExercise { //patients exercise time public static void main (String[]args) throws IOException{ Scanner in = new Scanner(new FileReader("values.txt")); double [] patientTimeRecords = new double [300]; int noExerciseCount=0, numPatients =0; double highest=0, lowest=0, avg=0, totalTime=0;
[Code] ....
However an error msg keeps popping up:
Exception in thread "main" java.util.NoSuchElementException at java.util.Scanner.throwFor(Scanner.java:907) at java.util.Scanner.next(Scanner.java:1530) at java.util.Scanner.nextDouble(Scanner.java:2456) at pastpapers.PatientExercise.main(PatientExercise.ja va:44)
line 44 is:patientTimeRecords[i]= in.nextDouble();
I'm trying to read from a file. we made an array of LinkedList and when I'm reading from the file i get a runtime error "index out of bounce in line 66"
import java.lang.*; import java.util.*; public class HashTester{ LinkedList_t [] hash; LinkedList_t [][] doubleHasher; int size;
I need to read from a text file given to us that has a list of books with authors names and book titles separated by an @ symbol for our delimiter. Here is the code I have right now, but it throws an ArrayIndexOutOfBoundsException at line 7...and I am unsure why?
import java.io.*; import java.util.*; public class Driver { public static void main(String[] args) { new Driver(args[0]);
[Code] ....
I realize that it must have something to do with my command line argument...but I am unsure what. Am I not entering the file name correctly?
I have an assignment on sorting, i kno i can get the sorting down but im having an issue with inputing the 512 ints in a file into an array. the instructor provided us with a file with 4 equal sets of ints. i tried to make my array of size [scan.nextInt()] and it cuts off the last 21 ints. and skips the first int. how can i get all of the integers in the text file into my array? this is what i have so far. if i hard code the array to size 50000 and then try to print the array it compiles but errors out when running it.
System.out.println("Please Enter text file in this format, XXXXX.txt :"); String file =fileName.nextLine(); Scanner scan = new Scanner(new File(file)); int [] data = new int[scan.nextInt()]; <-------here it skips first int int count= data.length; for (int i=0; i<data.length-1;i++) { data[i]=scan.nextInt(); } System.out.print(Arrays.toString(data));
rst 4 ints in output are: 501, 257, 390, 478...., supposed to be 492,501,390....and last ints are: ....88, 83, 79, 0 and supposed to be :88 83 79 77 76 72 71 71 66 57 56 48 48 41 33 30 23 23 18 17 15 13 9....it replace last ints with 0. why ? and how do i fix this. attached it the text file
I have a program I am trying to get together for class. Its a simple calendar, and I'm trying to save an array of dates to a file to be able to recall at will. I have done a fair amount of research but couldn't find a solid method to what I'm trying to do. I have a method that will check the inputted date's file to retrieve or save an entry. Here is where I'm stuck.
baseFile = new File("C:\Users\Ian\Documents\Eclipse (Java)"); private void getFile(String month, String year) throws IOException { String filename = new String(baseFile+"\"+month+year); File file = new File(filename); if(file.exists()){
[Code] ....
This is pretty much the most reasonable method I could find. this is called as a sort of plug for two other methods to call. Everything compiles, no errors or warnings, but no files are being created.
The project is a program that allows the user to enter students and enter grades for each student. One of the requirements is that if there is already a grade stored for the student that it will display the previous grade. IF the user then enters a new grade the new grade will be stored. IF the user simply presses enter (enters an empty string) nothing is done. I have everything working except for the requirement of doing nothing if the user enters an empty string. If I just press enter at this point I get a NumberFormatException.
The below code is a method "setTestGrades" from the student class. This method iterates through each student object stored in an array list and then checks if there is a previous grade (Requirement# unset grades have to default to -1) before allowing the user to set a new grade.
public void setTestGrades(int testNumber) { //Sets the grade for the specified test number for each student in the arraylist. testNumber -= 1; Scanner input = new Scanner(System.in); for (int i = 0; i < studentList.size(); i++) { System.out.println("Please enter the grade for Test #" + (testNumber + 1) + " For Student " + studentList.get(i).getStudentName());
I have a CSV file with 16K entries of a data table. Does Java work well with CSV file? So I found this code. And it seems its quite easy to read in the data I need. Say for example if I wanted a loop to randomly pick the first field of a specific line in the CSV data table. How would i go about coding that??????
The CSV looks like the above. and I basically would like to read in the Hand to get it to show in a text box and then randomly have the program ask me to correctly identify the True/False return for one of the SB/BB/UG/MP/CO/BN columns.
how to get the first few hex symbols of a file in java, for example if i input a pdf into my coding i want my program to output, e.g "25 46 44 38" ....
I have been able to print out the hex of a whole file but not managed to set a maximum read limit so that my code only takes a certain amount of values ....
I am implementing a recursive descent parser that recognizes strings in the language below. The input should be from a file "input.txt" and output should be to the console.
The grammar:
A -> I = E | E E -> T + E | T - E | T T -> F * T | F / T | F F -> P ^ F | P P -> I | L | UI | UL | (A) U -> + | - | ! I -> C | CI C -> a | b | ... | y | z L -> D | DL D -> 0 | 1 | ... | 8 | 9
An example session might look like this:
String read from file: a=a+b-c*d
The string "a=a+b-c*d" is in the language.
String read from file: a=a**b++c
The string "a=a**b++c" is not in the language.
Java Code: /**
* The Grammar * A -> I = E | E *E -> T + E | T - E | T *T -> F * T | F / T | F *F -> P ^ F | P *P -> I | L | UI | UL | (A) *U -> + | - | !
[code]....
My current output looks like this:
Java Code: The string read from file: a=a+b-c*d
The string "" is not in the language. mh_sh_highlight_all('java');
So it seems to be reading the input file correctly. My error seems to be on this part
I am trying to read a content of file downloaded from ftp and return it as a String. This is what I use:
Java Code:
import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import org.apache.commons.net.ftp.FTPClient; public class Test { public static void main(String [] args) throws IOException{ FTPClient ftp = new FTPClient();
[code]....
The code does not work, although all the links are correct.
I have to read from a file that is formatted like that :
name status friend END name status friend END .. etc
could be more than one line of friends, which where I have my problem. I can't get it to check if after the friend name the word "END"
I have tried to write a while loop inside the main while loop but it didn't work, and now I have tried to check that in a separate function which it also failed, thats my two while loops
BufferedReader br = null; FileReader fr = null; int getLine = 0; try { String line; fr = new FileReader(fileName); br = new BufferedReader(fr);
[Code] .....
Most of the time I got nullPointerException or missed up order for printing the file !!
I've looked at multiple sources and everyone is saying different stuff. Which one should I be using? FileWriter/FileReader, other people was saying PrintWriter, and one even said : "Formatter" which is the one I'm doubting mostly. My purposes for writing files is for like saving maps, saving high scores, etc.
I am trying to read from a text file that has that contains a list of stock tickers and pairs letting the user choose a ticker and provide analysis of stock. Given a ticker from the user provide
1) the max price, the min price and the avg price of the stock from all lines in the file. 2)Additionally the user should be able to find the stock with the highes price as well as the lowest price in the list. 3)lastly the user should be able to specify a different filename for the stock file.
Im trying to do part 1 and I am having trouble trying to read the whole text file and outputting the stock price with the max,min and avg. Am I heading towards the right track at least? Keep in mind I have just attempted trying to read the text file I have and not tried to find the max or min or avg Right now my code is crashing when I enter the stock ticker that is my primary concern.
package hw01b; import java.util.Scanner; import java.io.*; public class Hw01b { static Scanner in = new Scanner(System.in); static Scanner console = new Scanner(System.in);
Write a program that extracts words from a file. For the purposes of this program, a word is defined as a series of adjacent letters. Only print words that are at least four and no more than 12 letters long. Print each word on a different line.
The program should read the name of the file from the keyboard.
I need to get the filename from the user for this particular program. Usually I would have the name of the file prewritten into the source code like this....
Scanner input = new Scanner(new File("gettsy_burg.txt");
I tried different ways but I just can't seem to figure it out.... I guess what I'm really asking is how to rearrange Scanner input = new Scanner(new File("gettsy_burg.txt"); since I want the user to input the filename instead of the filename being prewritten by the programmer(me).
This is what I have so far to let the user for input....
Scanner keys = new Scanner(System.in); System.out.println("Enter the filename: "); String fileName = keys.nextLine(); keys = new Scanner(new File(fileName));
Write a program that extracts words from a file. For the purposes of this program, a word is defined as a series of adjacent letters. Only print words that are at least four and no more than 12 letters long. Print each word on a different line.
The program should read the name of the file from the keyboard.
I need to get the filename from the user for this particular program. Usually I would have the name of the file prewritten into the source code like this....
Scanner input = new Scanner(new File("gettsy_burg.txt");
I tried different ways but I just can't seem to figure it out....
