From string to integer .....

[javaken]

Suppose: you have folowing string of numbers ....

"1 2 3 4 5 6 "

How to convert it to an integer?? The procedure will also be possible if your string exists of 10 numbers .... "1 2 3 4 5 6 7 8 9 10 "

Thanks

 

[jisoo23]

You could use StringTokenizer. StringTokenizer interprets the whitespace between each character as a break. So all you have to do is run the string of numbers in a loop that breaks each number into a token (which is actually a string) then run Integer.parseInt(token) on each one. You can find references to StringTokenizer just about anywhere. I'm a little rusty at it but I think it may go like this:

int num;
String s = "1 2 3 4 5"; // String of numbers here
String token;
StringTokenizer st = new StringTokenizer(s);

token = st.nextToken; // Store first number in token

while(st.hasMoreTokens()){
  num = Integer.parseInt(token); // Convert string to int
  System.out.println(num); // Print int
  token = st.nextToken; // Move to next number in string
}

Good Luck,
Jisoo23

 

[jisoo23]

Oops, make sure to add "import java.util.*;" at the top.

 

[stefanwagner]

Ooops!
a) nextToken is method, needs ();
b) wouldn't work, if the String is "1" or " 17 "

// nextToken wrong here

while (st.hasMoreTokens ())
{
	token = st.nextToken (); 
	num = Integer.parseInt (token);
	System.out.println (num); 
}

seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[sedj]

stefan :

You using a StringTokenizer ? I thought you were always a fan of String.split() ?!

String s = "1 2 3 4 5";
String[] parts = s.split(" ");
for (int i = 0; i < parts.length; i++) {
  int j = Integer.parseInt(parts[i]);
  System.err.println(j);
}

 

[stefanwagner]

I was used to StringTokenizer and used it quiet often.
Since a few weeks, I know sun is discouraging the usage of ST (without deprecating it) and will prefer 'split' in future.

But this posting was a correction of jisoo23, so I tried to stay close to his example.

Of course I prefer scanner:

Scanner sc = Scanner.create (s);
while (sc.hasNext ()) 
{
	int i = sc.nextInt();
	System.out.println ("i="+i); 
}

(java 1.5 beta)


seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[sedj]

Cool - I have not had the time to try out 1.5 yet ...

 

[stefanwagner]

Well - it's faster changing than you type.

Todays 1.5 says:

Scanner sc = new Scanner (s);

instead of 'Scanner.create (s);'


seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[javaken]

What if your inputstring is null??? Because it becomes from a object ....

java.lang.NumberFormatException: For input string: "null"
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)

 

[stefanwagner]

test first:
if (s != null) ...

seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[jisoo23]

Woo, I haven't seen scanner yet. Looks like it's time to try 1.5 beta! My school always tossed stringtokenizer at me which is why I'm sorta used to using it =/ But looking like I'll move split or scanner, whole lot less code.