Java convert any integer to 4 digits

Question

This seems like an easy question. One of my assignments basically sends a time in military format (like 1200, 2200, etc) to my class.

How can I force the integer to be converted to 4 digits when it's received by my class? For example if the time being sent is 300, it should be converted to 0300.

EDIT: it turns out i didnt need this for my problem as i just had to compare the values. Thanks

Alex Abdugafarov · Accepted Answer · 2012-02-01T04:35:48.470

44

As simple as that:

String.format("%04d", 300)

For comparing hours before minutes:

int time1 =  350;
int time2 = 1210;
//
int hour1 = time1 / 100;
int hour2 = time2 / 100;
int comparationResult = Integer.compare(hour1, hour2);
if (comparationResult == 0) {
    int min1 = time1 % 100;
    int min2 = time2 % 100;
    comparationResult = Integer.compare(min1, min2);
}

Note:

Integer.compare(i1, i2) has been added in Java 1.7, for previous version you can either use Integer.valueOf(i1).compareTo(i2) or

int comparationResult;
if (i1 > i2) {
    comparationResult = 1;
} else if (i1 == i2) {
    comparationResult = 0;
} else {
    comparationResult = -1;
}

edited Feb 01 '12 at 04:35

answered Oct 11 '11 at 04:33

Alex Abdugafarov

6,112
7
35
59

Yah I thought of that because thats what we used for previous assignments, but thats for strings, in this case the times are integers and they gotta stay as ints cause i need to compare them afterwards – Cody Oct 11 '11 at 04:37
2

Then why the hell should you bother about number of digits in it? Just store it as a regular integer and print it via `String.format` when you need it to be zero-padded. – Alex Abdugafarov Oct 11 '11 at 04:39
well i basically have to compare 2 different times from military format and return the smaller one. but its not as simple as `if (time – Cody Oct 11 '11 at 04:42
so i figured it convert it to 4 digits and then split it after 2 where the first 2 are hour and 2nd 2 are minutes, then i can compare them easily – Cody Oct 11 '11 at 04:45
I've modified an answer, but you should modify the question accordingly - you didnt mentioned time comparison, only zero-padding. – Alex Abdugafarov Oct 11 '11 at 04:50
ahh ok, thank you very much :) I was looking at this problem the wrong way – Cody Oct 11 '11 at 04:55

score 1 · Answer 2 · answered Aug 09 '19 at 06:35

1


String a = String.format("%04d", 31200).substring(0, 4);
/**Output: 3120 */ 
System.out.println(a);


String b = String.format("%04d", 8).substring(0, 4);
/**Output: 0008 */
System.out.println(b);

answered Aug 09 '19 at 06:35

Q10Viking

982
8
9

1

The accepted answer is good,but not perfect when Integer has more than 4 digits. Such as number 31200. – Q10Viking Aug 09 '19 at 07:12
What you are trying to accomplish would be the substring. Combining the methods is redundant. – Abandoned Cart Jan 23 '20 at 17:05

Java convert any integer to 4 digits

2 Answers2

Note: