for-each construct

[bryan lim]

hi all,

can i use for-each loop on String?

like for( Char c : String) ? must it always be an array?

[Sridhar Santhanakrishnan]

It can also be an instance of java.lang.Iterable

[bryan lim]

so not for String?

[Sridhar Santhanakrishnan]

I dont think it works for Strings. But probably one of the ranchers has a different idea.

[Campbell Ritchie]

No, you can't use it for Strings. But there is a String method which can convert the String to an array, and it will work on that array.

[bryan lim]

thank you!

[dhiraj sardana]

You can only iterate an array or an object which is an instance of java.lang.iterable through for each loop.But you can iterate over string by first coverting it to char array like:

String str = "Hello world";
char[] chArr = str.toCharArray();
for(char c:chArr)
{
System.out.println(c);
}

[bryan lim]

thank you. now i understand

[Campbell Ritchie]

Please don't simply give out answers like that, dhiraj sardana. Ytbryan Lim would have remembered a lot better for working out the methods, rather than being told what to do.

[Rob Spoor]

Don't forget that toCharArray() creates a new array. This takes memory, and time to fill its contents. Using a basic for-loop using length() and charAt() is better:

for (int i = 0, length = str.length(); i < length; i++)
{
    char c = str.charAt(i);
    System.out.println(c);
}

[bryan lim]

ok thank you. i was considering the efficiency as well. your post comes in handy!

thank you everyone! javaranch is super!!