仅使用新行正则表达式将字符串拆分为整数

Question

I have an string and try it parsing to string array. The string look like:

c: 00000
u: 00001
h: 0001
r: 0010
s: 0011
e: 010
i: 0110
n: 0111

The above example is about only one string reference like String str = testClass.toString(); I merely want to put the 0 and 1's into a string array.

String filtered = str.replaceAll("[^0-1]","");
        String[] numbers = filtered.split("\n");
        for (String a : numbers) {
            System.out.println(a);
        }

I wrote the above code but it gives just one line output. How can it be fixed?

000000000100010010001101001100111

I intend as

str[0] = "00000";
...
str[7] = "0111"

Answer 1

The problem is that the '\\n' are also being replaced by an empty string when you call str.replaceAll("[^0-1]","") .

One possible approach is to replace all chars except digits AND '\\n' :

String filtered = str.replaceAll("[^01\n]","");
String[] list = filtered.split("\n");  

Another approach would be to directly split, keeping only "0" and "1" :

String[] list = str.split("[^01]+");

Answer 2

You can strip non numbers and replace with a hyphen - and then split them on - .

String filtered = str.replaceAll("[^0-1]+","-");
        String[] numbers = filtered.split("-");
        for (String a : numbers) {
            System.out.println(a);
        }

Answer 3

Just use

String filtered = str.replaceAll("[^0-1(\n)]","");

instead of

String filtered = `str.replaceAll("[^0-1]","");

Rest of your code is fine. Problem is, by using regex [^0-1] you are replacing everything except digits 0 and 1 with empty string. This in turn replaces \\n as well with empty string "" and hence all 0s and 1s get concatenated. You actually need to skip digits 0 , 1 and \\n .

Answer 4

I would say you can use a single split() to get your array of numbers, but you will have to ignore the first value there (which is empty). his will be more efficient than using split + replaceAll() .

public static void main(String[] args) {

    String s = "c: 00000" + "\n" + "u: 00001" + "\n" + "h: 0001";
    System.out.println(s);
    String[] arr = s.split("\\D+");
    System.out.println(Arrays.toString(arr));
}

O/P :

c: 00000
u: 00001
h: 0001
[, 00000, 00001, 0001] // ignore the first empty value.