CODEWITHSUNDEEP
javastring
rainman
rainman

Reputation: 2659

How to separate a string into substrings of two characters

I am trying to split strings in substrings of two chararters for example for the input: "ABCDE" i want to get the substrings "AB" "BC" "CD" "DE".

I tried with this:

String route = "ABCDE";
int i = 0;

 while(i < route.length()) {
            String sub = route.substring(i,i+2);
            System.out.println(sub);
            i++;
        }

but the index (i) gets out of range int the last iteration and causes an error. is there any way to do this without getting the index (i) out of range ?

Upvotes: 0

Views: 252

Answers (6)

Shettyh
Shettyh

Reputation: 1216

This should work fine

String route = "ABCDE";
if( route.length() > 2){
    int i = 0;
    do {
        String res = route.substring(i,i+2);
        System.out.println(res);
        i++;
    } while (i + 1 < route.length());
}
else{
    System.out.println(route);
}

Edit: Added boundary case for the string has length less than 2

Upvotes: 2

Maxwell
Maxwell

Reputation: 1

you can not use i < route.length(),because when i = 5, String sub = route.substring(i,i+2); the i+2=7,is out of index,so use i<route.length instead

Upvotes: -1

Mursaleen Ahmad
Mursaleen Ahmad

Reputation: 313

As denis already pointed out, the bug in the code is in the loop condition.

Should be: while(i < route.length() - 1) . However, how about simplifying this logic to use a for loop.

String route = "ABCDE";
for (int i=0; i+2<=route.length(); i++)
  System.out.println(route.substring(i,i+2));

Upvotes: 0

MasterBlaster
MasterBlaster

Reputation: 968

You are getting an StringIndexOutOfBoundsException because you are trying to access an index of the String that doesn't exist.

To fix this, change your loop condition from

while(i < route.length())

to

while(i < route.length() - 1)

Without the -1 on the last iteration of the while loop i + 2 is equal to 71 which is out of the Strings bounds.

Another (cleaner) solution to this problem is a for loop:

for(int i = 0; i < route.length() - 1; i++) {
    System.out.println(route.substring(j, j + 2));
}

The for loop in this situation is just shorter as the declaration, conditional, and increment statements are all in one line.

1: This 7 reduces to 6 since the endIndex of substring is exclusive.

Upvotes: 0

Denis
Denis

Reputation: 1229

You need to change the loop condition. 

while(i < route.length()-1)

In your code i goes till (length-1) and than in the substring(i,i+2) function you gives end index i+2. It is higher than largest index of string.

Also, As far as I know calling a library function in a loop condition is not considered a good practice.

  • In each iteration you call this function which is time consuming.
  • control goes to that subroutine in each iteration.

A good alternative to this would be to store the length in a variable and use that in a condition.

int temp = route.length()-1;
while(i<temp){

Upvotes: 4

ישו אוהב אותך
ישו אוהב אותך

Reputation: 29794

Add check for the size of the string to trap the error:

String route = "ABCDE";
int i = 0;

while(i < route.length()) {
  if(i < route.length() - 1) {
  String sub = route.substring(i,i+2);
  System.out.println(sub);
  } else {
    String sub = route.substring(i,i+1);
    System.out.println(sub);
  i++;
}

So whenever the i counter almost close to string size, get the last char.

Upvotes: 0

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