Java `printf` 中的“%d:%02d”是什么意思？
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What is the meaning of "%d:%02d" in `printf`?
提问by user34343
I have written the following code to convert hours into minutes. I got some help from the internet but I'm not 100% sure what "%d:%02d" means?
我编写了以下代码将小时转换为分钟。我从互联网上得到了一些帮助，但我不是 100% 确定“%d:%02d”是什么意思？
package time;
public class TimeAssignment {
public static void main(String[] args) {
// This program will convert hours into minutes
int time = 120;
int hours = time / 60;
int minutes = time % 60;
System.out.printf("%d:%02d", hours, minutes);
}
}
回答by janos
Even though I'm not 100% sure what “%d:%02d” means
即使我不是 100% 确定“%d:%02d”是什么意思
Here you go:
干得好：
%dmeans an integer:is a :%02dmeans an integer, left padded with zeros up to 2 digits.
%d表示整数:是一个：%02d表示一个整数，左填充零，最多 2 位。
More info at https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax
更多信息请访问https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax
回答by Jonathan
These are simply the way of printing the numbers. Look at this post java specifiersto understand what specifiers you are using.
这些只是打印数字的方式。查看这篇文章java 说明符以了解您正在使用哪些说明符。
In simple words, %d is an integer that in your case is "hours" and %02d is an integer that is shown as "xx" taken from the variable "minutes"
简单来说， %d 是一个整数，在您的情况下是“小时”，而 %02d 是一个整数，显示为“xx”，取自变量“分钟”
回答by MeBigFatGuy
The javadoc for PrintStream (which is what out is) http://docs.oracle.com/javase/8/docs/api/java/io/PrintStream.html#printf(java.lang.String,%20java.lang.Object...)
PrintStream 的 javadoc（这是什么）http://docs.oracle.com/javase/8/docs/api/java/io/PrintStream.html#printf(java.lang.String,%20java.lang.目的...）
shows what this format string should contain here:
显示此格式字符串应包含的内容：
http://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax
http://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax
回答by user4792294
"d" is "decimal" integer, there are also "o" for octal integer and "x"/"X" for hexadecimal integer. The rest is as Janos explained.
“d”是“十进制”整数，还有“o”表示八进制整数，“x”/“X”表示十六进制整数。其余的就像Janos解释的那样。
回答by Nimes
%2d outputs a decimal (integer) number that fills at least 2 character spaces, padded with empty space. And %d is similar to the %2d but it consists only one character space. Learn more from here about this %d, %02d, %f etcE.g.: 5 → " 5", 120 → "120"
%2d 输出一个十进制（整数）数，该数至少填充 2 个字符空格，并用空格填充。%d 与 %2d 类似，但它只包含一个字符空间。 从此处了解有关此 %d、%02d、%f 等的更多信息例如：5 → " 5", 120 → "120"
回答by TruVortex_07
In this question when we are talking about %dwe are talking about the hours, the :is the : on digital clocks, and by the %02dwe mean the minutes padded down with 0s on the left side up to two digits.
在这个问题中，当我们谈论时，%d我们谈论的是小时，:在数字时钟上，%02d我们的意思是分钟用左侧的 0 填充到两位数。
Therefore, %d:%02dmeans hr:min.
因此，%d:%02d意味着hr:min。
