Programming Forums > Application Development > Java

Dark Flare Knight · Jun 13th, 2005, 2:28 PM

How can i scan the entire data from a file with undefined number of lines?

Right now, i'm using BefferdReader identifier = new BufferedReader (new FileReader(filename.format)); but that scans 1 line at a time. i want to scan the entire file.

nnxion · Jun 13th, 2005, 4:35 PM

You want to read in the whole file or what?

Dark Flare Knight · Jun 13th, 2005, 6:51 PM

yes. i want to read the whole file

xavier · Jun 13th, 2005, 10:39 PM

(Toggle Plain Text)

String s="";
     String currentLine;
try{
    BufferedReader identifier = new BufferedReader (new FileReader("asd.txt"));
    for(;;){
     if((currentLine = identifier.readLine())==null)break;
     s=s+currentLine+"\n"; 
    }
    System.out.println(s);
    }catch (IOException e) {
       System.err.println("Error: " + e);
   }

Ooble · Jun 14th, 2005, 6:32 AM

Why the break statement?

(Toggle Plain Text)

while ((currentLine = identifier.readLine()) != null) {
    s = s + currentLine + "\n";
}

xavier · Jun 14th, 2005, 6:53 AM

Isn't that the same thing ? What are the benefits of while against for(;; ) ?

nnxion · Jun 14th, 2005, 7:12 AM

for(;; ) is faster as it doesn't have to compare anything.

kirkl_uk · Jun 14th, 2005, 7:35 AM

But surely you have to compare something to drop out of the loop anyway.

Ooble · Jun 14th, 2005, 9:29 AM

I believe it's generally accepted that if you can avoid the use of the break keyword, your solution will be more elegant. Your solution could have been written for ( ; (currentLine = identifier.readLine()) != null; ) - it's the same as mine.

skuinders · Jun 14th, 2005, 9:57 AM

Quote:

Originally Posted by Ooble

Why the break statement?

(Toggle Plain Text)

while ((currentLine = identifier.readLine()) != null) {
    s = s + currentLine + "\n";
}

this is the better solution

Jun 13th, 2005, 2:28 PM	#1
Dark Flare Knight Hobbyist Programmer Join Date: Mar 2005 Location: Canada Posts: 113 Rep Power: 4	Scanning data from a file How can i scan the entire data from a file with undefined number of lines? Right now, i'm using BefferdReader identifier = new BufferedReader (new FileReader(filename.format)); but that scans 1 line at a time. i want to scan the entire file. Last edited by Dark Flare Knight; Jun 13th, 2005 at 2:30 PM.

Jun 13th, 2005, 4:35 PM	#2
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	You want to read in the whole file or what? __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Jun 13th, 2005, 10:39 PM	#4
xavier Professional Programmer Join Date: Oct 2004 Location: .ro Posts: 383 Rep Power: 4	(Toggle Plain Text) String s=""; String currentLine; try{ BufferedReader identifier = new BufferedReader (new FileReader("asd.txt")); for(;;){ if((currentLine = identifier.readLine())==null)break; s=s+currentLine+"\n"; } System.out.println(s); }catch (IOException e) { System.err.println("Error: " + e); } String s=""; String currentLine; try{ BufferedReader identifier = new BufferedReader (new FileReader("asd.txt")); for(;;){ if((currentLine = identifier.readLine())==null)break; s=s+currentLine+"\n"; } System.out.println(s); }catch (IOException e) { System.err.println("Error: " + e); } __________________ Don't take life too seriously, it's not permanent !

Jun 14th, 2005, 6:32 AM	#5
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Why the break statement? (Toggle Plain Text) while ((currentLine = identifier.readLine()) != null) { s = s + currentLine + "\n"; } while ((currentLine = identifier.readLine()) != null) { s = s + currentLine + "\n"; } __________________ Me :: You :: Them Last edited by Ooble; Jun 14th, 2005 at 9:27 AM.

Jun 14th, 2005, 6:53 AM	#6
xavier Professional Programmer Join Date: Oct 2004 Location: .ro Posts: 383 Rep Power: 4	Isn't that the same thing ? What are the benefits of while against for(;; ) ? __________________ Don't take life too seriously, it's not permanent !

Jun 13th, 2005, 6:51 PM	#3
Dark Flare Knight Hobbyist Programmer Join Date: Mar 2005 Location: Canada Posts: 113 Rep Power: 4	yes. i want to read the whole file

Jun 14th, 2005, 7:12 AM	#7
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	for(;; ) is faster as it doesn't have to compare anything. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Jun 14th, 2005, 7:35 AM	#8
kirkl_uk Programmer Join Date: Apr 2005 Location: England Posts: 86 Rep Power: 4	But surely you have to compare something to drop out of the loop anyway. __________________ kirkl_uk

Jun 14th, 2005, 9:29 AM	#9
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	I believe it's generally accepted that if you can avoid the use of the break keyword, your solution will be more elegant. Your solution could have been written for ( ; (currentLine = identifier.readLine()) != null; ) - it's the same as mine. __________________ Me :: You :: Them

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Programming Forums > Application Development > Java

Scanning data from a file