Reputation: 141
I have a question. I'm struggling with a exercise where I am asked to get from user a string, a character which I want to duplicate in this string, and a number - how many times I want to duplicate. Eg: string input: dog; character: o; number:4. Output: doooog. My question is how can I achieve this result?
Scanner sc = new Scanner(System.in);
System.out.println("enter your string");
String text = sc.nextLine();
System.out.println("enter the character that will be repeated");
char character= sc.next().charAt(0);
System.out.println("enter the number of repetitions");
int repetitions = sc.nextInt();
for (int i = 0; i < text.length(); i++) {
char z = text.charAt(i);
if(z==character) {
// repeat character in string put by user * repetitions
}
}
System.out.println(text);
Upvotes: 0
Views: 3297
Reputation: 2188
If you are not using Java 8
you can try this.
StringBuilder builder = new StringBuilder();
String repetitionString = String.format("%" + repetitions + "s", character).replace(' ', character);
for (int i = 0; i < text.length(); i++) {
char z = text.charAt(i);
builder.append(z == character ? repetitionString : z);
}
text = builder.toString();
System.out.println(text);
In this solution we are using String.format
for repeating the character that we want instead of a loop.
String.format("%" + repetitions + "s", z).replace(' ', z)
This is similar to what we can do in Python
using the *
operator, ie
z * repeatitions
which will repeat the character in z
required number of times.
Another approach by which you can avoid the loops is using String.replace()
method.
String repetitionString = String.format("%" + repetitions + "s", character).replace(' ', character);
text = text.replace(String.valueOf(character), repetitionString);
System.out.println(text);
Upvotes: 0
Reputation: 195
The below should work:
StringBuilder buffer = new StringBuilder();
for (int i = 0; i < text.length(); i++) {
char z = text.charAt(i);
if(z==character) {
// repeat character in string put by user * repetitions
for (int j=1;j<=repetitions;j++){
buffer.append(z);
}
}else{
buffer.append(z);
}
}
System.out.println(buffer.toString());
Upvotes: 0
Reputation: 18
To complete your code, insert the following:
String ans="";
for (int i = 0; i < text.length(); i++) {
char z = text.charAt(i);
if(z==character) {
for(int j=0;j<repetitions;j++)
ans+=z;
}
else
ans+=z;
}
However, there is a far more elegant way of doing this:
String replacement="";
for(int i=0;i<repetitions;i++)
replacement+=character;
String ans = text.replaceAll(String.valueOf(character), replacement);
Upvotes: 0
Reputation: 60045
If you are using Java 8, you can use String.join
and replace like this :
String str = "dog";
int length = 4;
String s = "o";
str = str.replace(s, String.join("", Collections.nCopies(length, s)));// doooog
read more about Collections::nCopies
Upvotes: 2