Does java have the capablility to scan a line from a document and only print it if it is an integer? All the methods that I am looking at have you declare the variable that you are scanning.
easy enough to implement
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Fubar
{
private Scanner sc = null;
private File fooFile = new File(".\\petes\\brief3\\fooFile.txt");
public Fubar()
{
try
{
sc = new Scanner(fooFile);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
}
public void filterText()
{
if (sc != null)
{
while (sc.hasNextLine())
{
if (sc.hasNextInt())
{
System.out.println(sc.nextInt());
sc.nextLine();
}
else
{
sc.nextLine();
}
}
sc.close();
}
}
public static void main(String[] args)
{
Fubar f = new Fubar();
f.filterText();
}
}
input file, fooFile.txt:
text 1
text 2
text 3
29038
text 4
9232
text 5
-300
0
text 6
43
1021
443
last line
output:
29038
9232
-300
0
43
1021
443
THANKS PETE! That works great. Perhaps you can tell me why it is not reading every integer?
/*
* IntegerInputFile.java
*
* Created on July 17, 2007, 8:50 PM
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*/
/**
*
* @author pberardi
*/
import java.util.Scanner;
import java.io.*;
public class IntegerInputFile {
public static void main(String []args)throws Exception {
int url;
Scanner fileScan, urlScan;
int count=0;
fileScan = new Scanner(new File("IntegerInputFiledoc.txt"));
while (fileScan.hasNextLine()) {
if (fileScan.hasNextInt()) {
System.out.println(fileScan.nextInt());
count = count +1;
fileScan.nextLine();
} else {
fileScan.nextLine();
}
}
System.out.println("There are a total of "+count+" integers in IntegerInputFiledoc");
}
}
input file:
0 x 0 equals 0
1 x 1 equals 1
2 x 2 equals 4
3 x 3 equals 9
4 x 4 equals 16
5 x 5 equals 25
6 x 6 equals 36
7 x 7 equals 49
8 x 8 equals 64
9 x 9 equals 81
10 x 10 equals 100
11 x 11 equals 121
12 x 12 equals 144
OUTPUT:
init:
deps-jar:
Compiling 1 source file to C:\Practice Java\IntegerIntputFile\build\classes
compile:
run:
0
1
2
3
4
5
6
7
8
9
10
11
12
There are a total of 13 integers in IntegerInputFiledoc
BUILD SUCCESSFUL (total time: 0 seconds)
I messed up. this may be better, tho my regex is rusty:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Fubar
{
private Scanner sc = null;
private File fooFile = new File(".\\petes\\brief3\\fooFile.txt");
public Fubar() {
try
{
sc = new Scanner(fooFile);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
}
public void filterText()
{
if (sc != null)
{
while (sc.hasNextLine())
{
String line = sc.nextLine();
if (line.matches("(-|)\\d*"))
{
System.out.println(line);
}
}
sc.close();
}
}
public static void main(String[] args)
{
Fubar f = new Fubar();
f.filterText();
}
}
Addendum:
or this may be better:
if (line.matches("(-?)\\d*"))
Message was edited by:
petes1234
Can someone please tell me why I am get a inputmismatch exception?
You can find the file on my previous response.
import java.util.Scanner;
import java.io.*;
public class IntegerInputFile {
public static void main(String []args)throws Exception {
int count=0;
Scanner reader = new Scanner(new File("IntegerInputFiledoc.txt"));
while (reader.hasNextLine())
{
count = count +1;
int i = reader.nextInt();
System.out.println(i);
}
System.out.println("There are a total of "+count+" integers in IntegerInputFiledoc");
}
}
you need an if/else statement in your while loop. if it is an integer then do your stuff if not then scan next.
import java.util.Scanner;
import java.io.*;
class ManySquaresSkipWords
{
public static void main (String[] args) throws IOException
{
Filefile = new File("myData.txt");// create a File object
Scanner scan = new Scanner( file );// connect a Scanner to the file
int num, square;
while ( scan.hasNext() )// is there more data to process?
{
if ( scan.hasNextInt() ) // if it is an integer, get it
{
num = scan.nextInt();
square = num * num ;
System.out.println("The square of " + num + " is " + square);
}
else
scan.next();// read and discard non-integers
}
}
}
And go to this url on chapter 23
http://chortle.ccsu.edu/java5/cs151java.html
> you need an if/else statement in your while loop. if
> it is an integer then do your stuff if not then scan
> next.
>
> class ManySquaresSkipWords
> .......................
> while ( scan.hasNext() )// is there more data to
> process?
>{
> if ( scan.hasNextInt() ) // if it is an integer,
> get it
>{
> ......................
>
> And go to this url on chapter 23
> http://chortle.ccsu.edu/java5/cs151java.html
From what I understand, the OP wants to print a line only if it contains nothing but an integer (I could be wrong?). If this is so, the problem with the code above is that it will print integers if they are the first token on a line, even if non-integer tokens follow. That was my rational for using regex and String.match(regex) trying to see if the entire line matches the pattern for a generic integer.
