Java separate string from one single string

Question

I have String set which is "5X3I3M3X"

I want to separate 5X = 1X1X1X1X1X , depends on number in front of character "X"

So finally it could be 1X1X1X1X1X3I3M1X1X1X

I did it like below,

    String str = "5X3I3M3X";
    StringBuffer sBuffer = new StringBuffer("");

    for(int i = 1 ; i < str.length() ; i=i+2) {
        if( str.charAt(i) == 'X'){

            if(str.charAt(i-1) == 1){
                sBuffer.append(str.charAt(i-1)+""+str.charAt(i));
            }else{
                StringBuffer sBufferTemp = new StringBuffer("");

                for(int j=0 ; j < Character.getNumericValue(str.charAt(i-1)) ; j++){
                    sBufferTemp.append("1X");
                }

                sBuffer.append(sBufferTemp.toString());
            }
        } else {
            sBuffer.append(str.charAt(i-1)+""+str.charAt(i));
        }
    }
    System.out.println(sBuffer.toString());

And I want to know is there any simple way to separate that logic? note. If I want to add to separate 'I', then it should be dynamically change also like "1X1X1X1X1X1I1I1I3M1X1X1X"

I can change it my code extpend if (str.charAt(I) == 'I') ....

I hope there is another simple way to implement this.

Joop Eggen · Accepted Answer · 2016-02-25 19:31:15Z

1

Following your coding solution, I suggest the following changes:

String str = "5X3I3M3X";
StringBuilder sBuffer = new StringBuilder();
for (int i = 0; i < str.length(); ++i) {
    if (i + 1 < str.length()
            && str.charAt(i + 1) == 'X'
            && str.charAt(i) != '1'
            && Character.isDigit(str.charAt(i))) {
        int n = Character.getNumericValue(str.charAt(i));
        for (int j = 0 ; j < n; ++j) {
            sBufferTemp.append("1X");
        }
        ++i;
    } else {
        sBuffer.append(str.charAt(i));
    }
}

Use the newer and faster StringBuilder instead of the StringBuffer
Loop through all i, so the appending in the default case is straight-forward
The condition can be more complete, the check on '1' is not needed.
The char '1' must be compared against, not 1.

edited Feb 25, 2016 at 19:31

answered Feb 19, 2016 at 19:28

Joop Eggen

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Mr. Polywhirl · Accepted Answer · 2016-02-19 19:03:07Z

You can pass a configurable character array into a method. With this configuration, you can check if the current character is expandable.

Output from program below:

1X1X1X1X1X1I1I1I1M1M1M1X1X1X

public class StringExpander {
    public static void main(String[] args) {
        System.out.println(expand("5X3I3M3X", new char[] { 'X', 'I', 'M' }));
    }

    public static String expand(String str, char[] chArr) {
        StringBuffer buff = new StringBuffer();
        for (int i = 1; i < str.length(); i = i + 2) {
            char ch = str.charAt(i);
            if (contains(chArr, ch)) {
                if (str.charAt(i - 1) == 1) {
                    buff.append(str.charAt(i - 1)).append(str.charAt(i));
                } else {
                    StringBuffer tempBuff = new StringBuffer();
                    int repeat = Character.getNumericValue(str.charAt(i - 1));
                    for (int j = 0; j < repeat; j++) {
                        tempBuff.append(1).append(ch);
                    }
                    buff.append(tempBuff);
                }
            } else {
                buff.append(str.charAt(i - 1)).append(ch);
            }
        }
        return buff.toString();
    }

    private static boolean contains(char[] arr, char val) {
        for (char ch : arr) {
            if (ch == val) {
                return true;
            }
        }
        return false;
    }
}

0x44656E6E79 · Accepted Answer · 2016-02-19 21:35:36Z

0

I know this isn't exactly syntactic sugar whatsoever ..

String str = "5X3I3M3X";
char[] filter = new char[]{'X', 'I', 'M'};
StringBuffer stringBuffer = new StringBuffer("");

for (int i = 0; i < str.length(); i++) {
    if (i != 0 && new String(filter).contains(Character.toString(str.charAt(i))) && Character.isDigit(str.charAt(i-1))) {
        for (int j = 0; j < Character.getNumericValue(str.charAt(i-1)); j++) {
            stringBuffer.append("1" + str.charAt(i));
        }
    } else if (i < str.length()-1 && new String(filter).contains(Character.toString(str.charAt(i+1)))) {
        //do nothing
    }
    else {
        stringBuffer.append(str.charAt(i));
    }
}

edited Feb 19, 2016 at 21:35

answered Feb 19, 2016 at 21:15

0x44656E6E79

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