How to check how many letters are in a string in java?

How do you check how many letters are in a Java string?

How do you check what letter is in a certain position in the strin开发者_Go百科g (i.e, the second letter of the string)?

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A)

String str = "a string";
int length = str.length( ); // length == 8

http://download.oracle.com/javase/7/docs/api/java/lang/String.html#length%28%29

edit

If you want to count the number of a specific type of characters in a String, then a simple method is to iterate through the String checking each index against your test case.

int charCount = 0;
char temp;

for( int i = 0; i < str.length( ); i++ )
{
    temp = str.charAt( i );

    if( temp.TestCase )
        charCount++;
}

where TestCase can be isLetter( ), isDigit( ), etc.

Or if you just want to count everything but spaces, then do a check in the if like temp != ' '

B)

String str = "a string";
char atPos0 = str.charAt( 0 ); // atPos0 == 'a'

http://download.oracle.com/javase/7/docs/api/java/lang/String.html#charAt%28int%29

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If you are counting letters, the above solution will fail for some unicode symbols. For example for these 5 characters sample.length() will return 6 instead of 5:

String sample = "\u760c\u0444\u03b3\u03b5\ud800\udf45"; // 瘌фγε