在java中将字符串转换为int

Question

i have a string that has a int value in it. i just want to extract the int value from the string and print.

String str="No. of Days : 365";
String daysWithSplChar = str.replaceAll("[a-z][A-Z]","").trim();
char[] ch = daysWithSplChar.toCharArray();
StringBuffer stb = new StringBuffer();
for(char c : ch)
{
  if(c >= '0' && c <= '9')
   {
      stb.append(c);
   }
}

int days = Integer.ParseInt(stb.toString());

is there any better way than this. please let me know.

Answer 1

try String.replaceAll

    String str = "No. of Days : 365";
    str = str.replaceAll(".*?(\\d+).*", "$1");
    System.out.println(str);

you will get

365

Answer 2

Another way of using regex (other than the way suggested by @EvgeniyDorofeev) which is closer to what you did:

str.replaceAll("[^0-9]","");   // give you "365"

which means, replace everything that is not 0-9 with empty string (or, in another word, remove all non-digit characters)

This is meaning the same, just a matter of taste which one is more comfortable to you:

str.replaceAll("\\D","");   // give you "365"

Answer 3

Scanner in = new Scanner("Hello123").useDelimiter("[^0-9]+");
int integer = in.nextInt();

This will get you the integer

Answer 4

following code gives you integer value

  String str = "No. of Days : 365";
        str = str.replaceAll(".*?(\\d+)", "$1");
        System.out.println(str);
        Integer x = Integer.valueOf(str);//365 in integer type
           System.out.println(x+1);//output 366