Java String Format: "%0" and "d%s"

Question

I would like to know what is the meaning of "%0" and "d%s" in java when formatting a string.

String.format("%0"+ (8 - "Apple".length() )+"d%s",0 ,"Apple");

Output:

000Apple

I was searching for a way to format a string with leading zeros, and that code does the work, but I don't know why it works.

Dave Newton · Accepted Answer · 2015-08-14 17:26:52Z

12

%d means number. %0nd means zero-padded number with a length.

You build n by subtraction in your example.

%s is a string.

Your format string ends up being this:

"%03d%s", 0, "Apple"

So you print a zero-padded 0 that's three digits long, and the string "Apple".

answered Aug 14, 2015 at 17:26

Dave Newton

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