Extracting Integers from Strings

The following snippet of source code extracts a single digit from a String and converts it to an int. The String.charAt() method takes a zero-based index of the position of the character to be extracted from the String and the Character.digit() method takes the String from which to extract the digit and the radix.

In the example below I pass 0 to the charAt() method since I want the first character extracted and I pass 10 as the radix since I’m working in base 10.


String myString = "3blindmice";
int digit = Character.digit(myString.charAt(0), 10);
System.out.println("Digit: " + digit);


Output: 3

If the position passed to charAt is not a valid position within the String then a java.lang.StringIndexOutOfBoundsException is thrown.

If the radix is not between Character.MIN_RADIX and Character.MAX_RADIX, -1 is returned.

Comments, alternate solutions and related snippets of code are welcome.

Joshua Smith

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References:

API for java.lang.Character.digit(char, int)

API for java.lang.String.charAt(int)

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