如何在Scala中使用java.String.format？

本文翻譯自：How to use java.String.format in Scala?

I am trying to use a .format method of a string. 我正在嘗試使用字符串的.format方法。 But if I place %1, %2, etc. in the string, java.util.UnknownFormatConversionException is thrown pointing to a confusing Java source code piece: 但是如果我在字符串中放置％1，％2等，則會拋出java.util.UnknownFormatConversionException指向令人困惑的Java源代碼段：

private void checkText(String s) {

    int idx;

    // If there are any '%' in the given string, we got a bad format
    // specifier.
    if ((idx = s.indexOf('%')) != -1) {
        char c = (idx > s.length() - 2 ? '%' : s.charAt(idx + 1));
        throw new UnknownFormatConversionException(String.valueOf(c));
    }
}

From this I understand that % char is forbidden. 據我所知， % char是被禁止的。 If so, then what should I use for argument placeholders? 如果是這樣，那麼我應該將什麼用於參數佔位符？

I use Scala 2.8. 我使用Scala 2.8。

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#1樓

參考：https://stackoom.com/question/FVIU/如何在Scala中使用java-String-format

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#2樓

Here is a list of formatters used with String.format() 以下是與String.format（）一起使用的格式化程序列表

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html

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#3樓

官方參考是Formatter類。

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#4樓

In Scala 2.10 在Scala 2.10中

val name = "Ivan"
val weather = "sunny"

s"Hello $name, it's $weather today!"

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#5樓

You can use this; 你可以用這個;

String.format("%1$s %2$s %2$s %3$s", "a", "b", "c");

Output: 輸出：

abbc ABBC

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#6樓

This is a list of what String.format can do. 這是String.format可以執行的操作的列表。 The same goes for printf printf

int i = 123;
o.printf( "|%d|%d|%n" ,       i, -i );      // |123|-123|
o.printf( "|%5d|%5d|%n" ,     i, -i );      // |  123| –123|
o.printf( "|%-5d|%-5d|%n" ,   i, -i );      // |123  |-123 |
o.printf( "|%+-5d|%+-5d|%n" , i, -i );      // |+123 |-123 |
o.printf( "|%05d|%05d|%n%n",  i, -i );      // |00123|-0123|

o.printf( "|%X|%x|%n", 0xabc, 0xabc );      // |ABC|abc|
o.printf( "|%04x|%#x|%n%n", 0xabc, 0xabc ); // |0abc|0xabc|

double d = 12345.678;
o.printf( "|%f|%f|%n" ,         d, -d );    // |12345,678000|     |-12345,678000|
o.printf( "|%+f|%+f|%n" ,       d, -d );    // |+12345,678000| |-12345,678000|
o.printf( "|% f|% f|%n" ,       d, -d );    // | 12345,678000| |-12345,678000|
o.printf( "|%.2f|%.2f|%n" ,     d, -d );    // |12345,68| |-12345,68|
o.printf( "|%,.2f|%,.2f|%n" ,   d, -d );    // |12.345,68| |-12.345,68|
o.printf( "|%.2f|%(.2f|%n",     d, -d );    // |12345,68| |(12345,68)|
o.printf( "|%10.2f|%10.2f|%n" , d, -d );    // |  12345,68| | –12345,68|
o.printf( "|%010.2f|%010.2f|%n",d, -d );    // |0012345,68| |-012345,68|

String s = "Monsterbacke";
o.printf( "%n|%s|%n", s );                  // |Monsterbacke|
o.printf( "|%S|%n", s );                    // |MONSTERBACKE|
o.printf( "|%20s|%n", s );                  // |        Monsterbacke|
o.printf( "|%-20s|%n", s );                 // |Monsterbacke        |
o.printf( "|%7s|%n", s );                   // |Monsterbacke|
o.printf( "|%.7s|%n", s );                  // |Monster|
o.printf( "|%20.7s|%n", s );                // |             Monster|

Date t = new Date();
o.printf( "%tT%n", t );                     // 11:01:39
o.printf( "%tD%n", t );                     // 04/18/08
o.printf( "%1$te. %1$tb%n", t );            // 18. Apr