Random access line from the file..

Question

hii gus..

i want to access random data from the. file so can any one tell me..how to achieve it..
and. also send the syntax for demonstration..

i was trying to solve it.throw many website but at last a.i not able..

so plz frnd tell me how to write the code for it..

thanks in advance

Answer 1

Use LinkedHashMap or your HashMap won't keep the order in which you put the values in it.
// Instantiation
LinkedHashMap map = new LinkedHashMap();
// Put an element to the map
map.put(new Integer(0), "firstLineOfFile");
// Print elements of the map
Set set = map.entrySet();
Iterator i = set.iterator();
while(i.hasNext()) {
Map.Entry me = (Map.Entry)i.next();
System.out.println(me.getKey() + " " +
me.getValue());
}

Answer 2

You have to replace the string in my example by the line you read from the file (BufferedReader, readLine method). And of course increment the keys. I recommend a while loop surrounding the map.put statement.
while(bufferedReader.readLine!=null) will be true as long there are lines.
Putting it all together provides you the entire code.
If you have further problems, publish your code at the playground, then I will help you bugfixing.

Answer 3

You will need to read the whole file to a collection, which is accessible by a key and can store a String, e.g. a LinkedHashMap. Use an int key. Then use Math.random() to access a random value in the range of the first key to the last key.

Answer 4

Another solution but you need to know exactly how many lines the file contains:
// rand can be defined by Math.random(), for
// the range you need the number of
// lines in your files.
String line = Files.readAllLines(Paths.get("file.txt")).get(rand)

Answer 5

Then extend LinkedHashMap and overwrite the toString method. You can return any string you want from that.

Answer 6

can u tell me..how to add the file in the collection..actually i am already using hashmap..

Answer 7

thank u Tashi N.

i m going to check it..after short period,i will respond.

Answer 8

hey..i want to put an eternal file in this..so how can do it.

Answer 9

okay thank a lot tashi

Answer 10

yes..i did like this..but problem is there that..
the print statement also show the key with value.