Is it possible to group a string every nth character?
For example, suppose I have a string containing the following: "Hello how are you"
What I'm trying to do is if the user inputs 4, then based on the integer, break into 4 groups and assign those to strings.
1 2 3 4 1 2 3 4 1 2 3 4 1 2
H E L L O H O W A R E Y O U
All the letters that has 1 assigned will be group 1, similarly, all the letters that has 2 assigned will be group 2.
Group 1 - "HOAO", Group 2 - "EHRU", Group 3 - "LOE", Group 4 - "LWY"
Below is what I have so far
import java.util.*;
class groupChar {
static void groupLetters(String str, int n) {
String result="";
for(int i = 0; i < str.length(); i = i n){
result = result str.charAt(i);
}
System.out.println(result);
}
public static void main(String[] args) {
Scanner inputMessage = new Scanner(System.in);
System.out.println("Enter string : ");
String message = inputMessage.nextLine();
System.out.println("Enter a number : ");
Scanner inputNumber = new Scanner(System.in);
int number = Integer.parseInt(inputNumber.nextLine());
System.out.println("String is - " message);
System.out.println("Number is - " number);
groupLetters(message, number);
}
}
So far I'm only able to create one group based on the user input.
CodePudding user response：
You can approach this problem using Map to track all the groups and using StringBuilder to construct the individual group.
Firstly, we need to generate a HashMap populated with entries having the keys corresponding to the indices of the groups and empty StringBuilders as *values.
Then we have to iterate over the given string, maintaining two indices: i - position in the string and groupId - index of the group. At iteration step, we need to update the current group by appending the current character.
That's how it can be implemented:
public static Map<Integer, StringBuilder> groupLetters(String str, int n) {
Map<Integer, StringBuilder> groupByGroupId = createGroups(n);
for (int i = 0, groupId = 1; i < str.length(); i , groupId = (groupId % n) 1) {
groupByGroupId.get(groupId).append(str.charAt(i));
}
return groupByGroupId;
}
public static Map<Integer, StringBuilder> createGroups(int n) {
Map<Integer, StringBuilder> groupByGroupId = new HashMap<>();
for (int i = 1; i <= n; i ) {
groupByGroupId.put(i, new StringBuilder());
}
return groupByGroupId;
}
main
public static void main(String[] args) {
for (Map.Entry<Integer, StringBuilder> entry: groupLetters("hellohowareyou", 4).entrySet()) {
System.out.println("Group " entry.getKey() " -> " entry.getValue());
}
}
Output:
Group 1 -> hoao
Group 2 -> ehru
Group 3 -> loe
Group 4 -> lwy
CodePudding user response：
The suggested solution would be to use a map or dictionary with <int,List>. But I recommend the most simple and understandable way without using Map based on your code.
I used the same example as you provided, but starting from 0 would make it easier to understand the code.
0 1 2 3 4 5 6 7 8 9 10 11 12 13
0 1 2 3 0 1 2 3 0 1 2 3 0 1
H E L L O H O W A R E Y O U
The Algorithm:
- Group 1 : 0,(0 (1 x 4)),(0 (2 x 4)),(0 (3 x 4)) ...
- Group 2 : 1,(1 (1 x 4)),(1 (2 x 4)),(1 (3 x 4)) ...
- Group 3 : 2,(2 (1 x 4)),(2 (2 x 4)),(2 (3 x 4)) ...
Therefore, Group a 1 : a, (a (1 x N)), (a (2 x N)), (a (3 x N))... WHERE the total number of elements in each group is
(total number of Char in string) / (number of droup) 1
Code
We used a for loop for a AND a for loop for the increment 1,2,3...
Therefore, I have modified your code to meet the requirement :
static void groupLetters(String str,int n) {
//Remove the string space and to UPPER CASE
str = str.toUpperCase().replaceAll("\\s ","");
for(int a = 0; a < n; a ){
String result = "";
//Get the Char in Group a with the algorithm mentioned above
for(int i = 0; i < str.length() / n 1; i ){
if(a (i * n) < str.length()){
result = result str.charAt(a (i * n));
}
}
System.out.println("Group " (a 1) ": " result);
}
}
public static void main(String[] args) {
Scanner inputMessage = new Scanner(System.in);
System.out.println("Enter string : ");
String message = inputMessage.nextLine();
System.out.println("Enter a number of group gonna break into : ");
Scanner inputNumber = new Scanner(System.in);
int number = Integer.parseInt(inputNumber.nextLine());
System.out.println("String is - " message);
System.out.println("Number of Group is - " number);
groupLetters(message,number);
}
OUTPUT:
String is - Hello how are you
Number of Group is - 4
Group 1: HOA
Group 2: EHR
Group 3: LOE
Group 4: LWY
CodePudding user response：
Splitter can be used to split text by length
com.google.common.base.Splitter , see -> https://www.geeksforgeeks.org/splitter-class-guava-java/
I slightly modified the code :
import java.util.Scanner;
import com.google.common.base.Splitter;
public class test {
public static String result="";
public static int index = 0;
static void groupLetters(String str, int n) {
str = str.replaceAll("\\s", "");
Iterable<String> fullString = Splitter.fixedLength(n).split(str);
int length = str.length() % n == 0 ? str.length() / n : (str.length() / n) 1;
for(int i = 0; i < length 1; i ){
fullString.forEach(s->{
if(s.length()>index){
result =s.charAt(index) "";
}
});
result =" ";
index ;
}
System.out.println(result);
}
public static void main(String[] args) {
Scanner inputMessage = new Scanner(System.in);
System.out.println("Enter string : ");
String message = inputMessage.nextLine();
System.out.println("Enter a number : ");
Scanner inputNumber = new Scanner(System.in);
int number = Integer.parseInt(inputNumber.nextLine());
System.out.println("String is - " message);
System.out.println("Number is - " number);
groupLetters(message, number);
}
}