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I have a text file with some information in it, which looks something like displayed below. I'm supposed to read the file after a specific word occurs (Complete Population), and store the vertically aligned values in each line like in an array (could be arraylist too)

What the file looks like - 

Tue May 14 08:27:25 EST 2013 
mating_pool=80
mutation_dist=3
algo_name=ARMO

Complete Population 

8.78792396E8 7.45689508E8 8.37899916E8 9.52778502E8 8.47061622E8 
8.80017166E8 7.50224432E8 8.23658404E8 9.51664198E8 8.49145008E8 
8.85724416E8 7.48191542E8 7.61295532E8 1.00892758E9 8.52389824E8 
8.96069156E8 7.11234404E8 7.68007126E8 9.7238065E8 8.5759227E8 
8.96193522E8 7.11177522E8 7.67777526E8 9.72449466E8 8.5763106E8 
8.95546766E8 7.1112849E8 7.68311754E8 9.71998374E8 8.57960886E8 
8.95480802E8 7.11023308E8 7.68223532E8 9.72097758E8 8.5803376E8
8.9549393E8 7.11015392E8 7.68194136E8 9.72079838E8 8.5804897E8 
8.95467666E8 7.11364074E8 7.68318732E8 9.7189094E8 8.58053462E8 
8.95574386E8 7.11095656E8 7.68187948E8 9.71985272E8 8.58095624E8 
8.95390774E8 7.11052654E8 7.684207E8 9.72098718E8 8.58105648E8

What I have tried
I'm able to read only one line of the numbers and not sure how to add numbers vertically.

Any help is appreciated.

sinsuren
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712sash
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  • Please show your code. How are you reading one line? – AlexR Aug 04 '14 at 07:22
  • I looked up this thread which read the line number specified using this package **org.apache.commons.io.FileUtils;**. I'm not sure how to loop through the lines containing numbers starting from a particular line. This is what my code looks like - `String population = FileUtils.readLines(file).get(30); System.out.println(population);` – 712sash Aug 04 '14 at 07:36

2 Answers2

2

Well, there actually is no issue here. You just need to code it. There are some nice pieces of code in this thread. Do something like this: 

 BufferedReader br = new BufferedReader(new FileReader(file));
 String line;
 while ((line = br.readLine()) != null) {
  if (line.contains("Complete Population"){
    // do something
    break; // breaks the while loop
  }
 }

 // we reached the section with numbers
 while ((line = br.readLine()) != null) {
    // use String.split to split the line, then convert 
    //the values to double and process them.  
 }

}

br.close();

Community
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Emil Salageanu
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  • isn't the second while start going to read the file from the beginning again? – 712sash Aug 04 '14 at 08:12
  • No, You use the br object, it would continue to read lines from the file. If you don't like the 2 whiles, you could have a single while with a (boolean) flag "passedCompletePopulationLine". At each iteration you check the flag and execute your code accordingly. – Emil Salageanu Aug 04 '14 at 08:15
  • While looks more approachable. I added `String line1 = br.readLine(); System.out.println(line1);` in the second while loop but it seems to display an alternate line of numbers for some reason. I can't figure out why. – 712sash Aug 04 '14 at 08:44
0

Use a BufferedReader to wrap a FileReader on the file, and then use nextLine() to read each line. Create a Pattern object with regex ".*Complete Population.*", and use a Matcher on that Pattern to check each line (looping with condition that the BufferedReader's nextLine() doesn't return null -- since null indicates end of file reached.) When a line matches, begin processing subsequent lines to form arrays.

I'm not sure what you mean by "the vertically-aligned values", but if you mean the space-separated values on each line as an array, use String.split("\\s+"); on each line to split on whitespace, returning an array of Strings.

If by vertical arrays, you mean the first elements on each of the lines, then the second elements on each of the lines, and so on: You can store these arrays of Strings retrieved by String.split("\\s+")ing each line together as a 2-d array by placing each array into a main array which will hold them all (an array of arrays of per-line Strings), and then, when the full read-in is done and end of file is reached, go back to this 2-d array and access element [0] of each line to get a list of the first items on each line, element[1] of each line to get a list of the second items on each line, and so on. If you want, you can store these (effectively vertical lists of items on the lines) in another set of arrays.

Mer
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