Get int from String, also containing letters, in Java

Question

How can I get the int value from a string such as 423e - i.e. a string that contains a number but also maybe a letter?

Integer.parseInt() f

Answer 1

Just go through the string, building up an int as usual, but ignore non-number characters:

int res = 0;
for (int i=0; i < str.length(); i++) {
    char c = s.charAt(i);
    if (c < '0' || c > '9') continue;
    res = res * 10 + (c - '0');
}