Java - Parsing Text File

Question

I have an input text file in this format:

<target1> : <dep1> <dep2> ...
<target2> : <dep1> <dep2> ...
...

And a method that takes two parameters

function(target, dep);

I need to get this parsing to call my method with each target and dep eg:

function(target1, dep1);
function(target1, dep2);
function(target1, ...);
function(target2, dep1);
function(target2, dep2);
function(target2, ...);

What would be the most efficient way to call function(target,dep) on each line of a text file? I tried fooling around with the scanner and string.split but was unsuccessful. I'm stumped.

Thanks.

No code to post. My original thought was to save each line into a string but since the total number to dep's is unknown it would need some sort of loop correct? — Mike
– Mike, Commented Apr 28, 2011 at 13:59
Read the file line by line... split each line on ':' then the first part is the target, and then the second part is all the deps, which can be separated by splitting on space — Java Drinker
– Java Drinker, Commented Apr 28, 2011 at 14:00

Brian Roach · Accepted Answer · 2011-04-28 14:10:59Z

11

Read line into String myLine
split myLine on : into String[] array1
split array1[1] on ' ' into String[] array2
Iterate through array2 and call function(array1[0], array2[i])

So ...

FileReader input = new FileReader("myFile");
BufferedReader bufRead = new BufferedReader(input);
String myLine = null;

while ( (myLine = bufRead.readLine()) != null)
{    
    String[] array1 = myLine.split(":");
    // check to make sure you have valid data
    String[] array2 = array1[1].split(" ");
    for (int i = 0; i < array2.length; i++)
        function(array1[0], array2[i]);
}

edited Apr 28, 2011 at 14:10

answered Apr 28, 2011 at 14:00

Brian Roach

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4 Comments

Mike Over a year ago

Load each line into its own string? Or use while(hasNextLine)? I understand the splitting and iterate but how would each line become it's own string?

jitm Over a year ago

I've just provided this info :)

Mike Over a year ago

I understand it now. Thanks for posting.

Brian Roach Over a year ago

added the FileReader and loop.

jitm · Accepted Answer · 2011-04-28 14:03:54Z

2

The firstly you have to read line from file and after this split read line, so your code should be like:

FileInputStream fstream = new FileInputStream("your file name");
// or using Scaner
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
//Read File Line By Line
while ((strLine = br.readLine()) != null)   {
  // split string and call your function
}

answered Apr 28, 2011 at 14:03

jitm

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1 Comment

CanCoder Over a year ago

where should the file be stored? in the project folder or src folder?

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