How to read integer values from text file

Question

Possible Duplicate    Java  Reading integers from a file into an array       I want to read integer values from a text file say contactids txt  in the file i have values like  12345 3456778 234234234 34234324234   i Want to read them from a text file   please help

User · Answer

Try this -  File file   new File  contactids txt    Scanner scanner   new Scanner file   while scanner hasNextLong           Read values here like long input   scanner nextLong

User · Answer

How large are the values  Java 6 has Scanner class that can read anything from int  32 bit   long  64-bit  to BigInteger  arbitrary big integer    For Java 5 or 4  Scanner is there  but no support for BigInteger  You have to read line by line  with readLine of Scanner class  and create BigInteger object from the String

User · Answer

use FileInputStream s readLine   method to read and parse the returned String to int using Integer parseInt   method

User · Answer

You can use a Scanner and its nextInt   method  Scanner also has nextLong   for larger integers  if needed

User · Answer

I would use nearly the same way but with list as buffer for read integers   static Object   readFile String fileName        Scanner scanner   new Scanner new File fileName        List lt Integer gt  tall   new ArrayList lt Integer gt         while  scanner hasNextInt              tall add scanner nextInt                return tall toArray

User · Answer

You might want to do something like this  if you re using java 5 and more    Scanner scanner   new Scanner new File  tall txt     int    tall   new int  100   int i   0  while scanner hasNextInt           tall i      scanner nextInt        Via Julian Grenier from Reading Integers From A File In An Array

[java] How to read integer values from text file

Examples related to java