What is the best way to convert an integer into a character array?
Input: 1234
Output: {1,2,3,4}
Keeping in mind the vastness of Java language what will be the best and most efficient way of doing it?
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1I am looking for an efficient way. I can think of getting each digit out by %10, converting it to char and adding to an array. And at last reverse the array. Any better method??some_other_guy– some_other_guy2012-08-30 08:29:19 +00:00Commented Aug 30, 2012 at 8:29
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1stackoverflow.com/a/19237615/912319Kanagavelu Sugumar– Kanagavelu Sugumar2019-08-16 10:13:32 +00:00Commented Aug 16, 2019 at 10:13
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7 Answers
int i = 1234;
char[] chars = ("" + i).toCharArray();
1 Comment
Thomas
Hey would you be able to explain how (""+i) part of that solution works are you just saying empty string + int = a string of that int.
You could try something like:
String.valueOf(1234).toCharArray();
Comments
Try this...
int value = 1234;
char [] chars = String.valueOf(value).toCharArray();
Comments
You can convert that integer to string and then convert that string to char arary:-
int i = 1234;
String s = Integer.toString(i);
Char ch[] = s.toCharArray();
/*ch[0]=1,ch[1]=2,ch[2]=3,ch[3]=4*/
Comments
This will convert an int to a 2 char array. If you are trying to get the minimum amount of chars, try this.
//convert int to char array
int valIn = 111112222;
ByteBuffer bb1 = ByteBuffer.allocate(4);
bb1.putInt(valIn);
char [] charArr = new char[4];
charArr[0] = bb1.getChar(0);
charArr[1] = bb1.getChar(2);
//convert char array to int
ByteBuffer bb2 = ByteBuffer.allocate(8);
bb2.putChar(0,charArr[0]);
bb2.putChar(2,charArr[1]);
long valOut = bb2.getInt(0);
Comments
I was asked this question in google interview. If asked in interviews use module and division. Here is the answer
List<Integer> digits = new ArrayList<>();
//main logic using devide and module
for (; num != 0; num /= 10)
digits.add(num % 10);
//declare an array
int[] arr = new int[digits.size()];
//fill in the array
for(int i = 0; i < digits.size(); i++) {
arr[i] = digits.get(i);
}
//reverse it.
ArrayUtils.reverse(arr);
Comments
Say that you have an array of ints and another method that converts those ints to letters, like for a program changing number grades to letter grades, you would do...
public char[] allGradesToLetters()
{
char[] array = new char[grades.length];
for(int i = 0; i < grades.length; i++)
{
array[i] = getLetter(grades[i]);
}
return array;
}
