Having trouble converting a string into an integer-CodePudding

public static int[] booleanToBinary(boolean[] b) {
    int[] arr = new int[b.length];
    for(int i = 0; i < b.length; i  ) {
        if(b[i] == true) {
             arr[i] = 1;
        }
        else{arr[i] = 0;};
        }
    
    return arr;
}



public static int binaryToInt(boolean[] b) {
    int[] a = booleanToBinary(b);
    String c = Arrays.toString(a);
    System.out.println(c);
    int decimal = Integer.parseInt(c, 2);
    
        System.out.println(decimal);
    

    
    return decimal;
    
}

 public static void main(String[] args) {
    boolean[] test = {false, true, false, true};
    System.out.println(Arrays.toString(booleanToBinary(test)));
    System.out.println(binaryToInt(test));
    
}

Blockquote I'm trying to turn the binary value into an Integer value, and I'm trying to do that using the binaryToInt method, and an NumberExceptionFormat is happening, I know that this error happens when java cannot convert a String into an Integer, can someone help me to fix this this error

CodePudding user response：

Upon converting the array of 0's and 1's to string using Arrays.toString, all the non-zeros and non-ones may be removed from the String using String::replaceAll:

public static int binaryToInt(boolean[] b) {
    int[] a = booleanToBinary(b);
    String c = Arrays.toString(a).replaceAll("[^01]", );
    System.out.println(c);
    int decimal = Integer.parseInt(c, 2);
    
    System.out.println(decimal);
    return decimal;    
}

Then the test:

 boolean[] test = {false, true, false, true};
System.out.println(Arrays.toString(booleanToBinary(test)));
System.out.println(binaryToInt(test));

prints:

[0, 1, 0, 1]
0101
5
5

However, here the order of bits is inversed as the arrays are printed starting from 0 to n (from lower bits).

CodePudding user response：

To convert a list of booleans to an int equivalent, try it like this. No need to use any strings or integer parsing methods.

// 100111 the value = 39
boolean[] b = {true, false, false, true, true, true};
int v = binaryToInt(b);
System.out.println(v);

prints

first multiply decimal by 2
then add 1 or 0 as appropriate.
continue, multiply and adding

public static int binaryToInt(boolean[] bools) {
    int decimal = 0;
    for (boolean b : bools) {
        decimal = decimal * 2   (b ? 1 : 0);
    }
    return decimal;
}

Similarly, to convert an array of booleans to an array of 1's or 0's.

public static int[] booleanToBinary(boolean[] bools) {
    int[] arr = new int[bools.length];
    int i = 0;
    for (boolean b : bools) {
        arr[i  ] = b ? 1 : 0;
    }
    return arr;
}

Note if you want to just convert your boolean array into a binary string, this will work.

public static String booleanToBinaryString(boolean[] bools) {
    int[] arr = new int[bools.length];
    String result = "";
    for (boolean b : bools) {
        result  = b ? 1 : 0;
    }
    return result;
}

System.out.println(booleanToBinaryString(b));

prints