可以使用单个重复字符将 Java 字符串初始化为特定长度吗
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Can one initialise a Java String with a single repeated character to a specific length
提问by Ron Tuffin
I'd like to create a function that has the following signature:
我想创建一个具有以下签名的函数：
public String createString(int length, char ch)
It should return a string of repeating characters of the specified length.
For example if length is 5 and ch is 'p' the return value should be:
它应该返回一串指定长度的重复字符。
例如，如果长度为 5 且 ch 为“p”，则返回值应为：
ppppp
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Is there a way to do this without looping until it is the required length?
And without any externally defined constants?
有没有办法在不循环的情况下做到这一点，直到达到所需的长度？
并且没有任何外部定义的常量？
采纳答案by Joel Shemtov
char[] chars = new char[len];
Arrays.fill(chars, ch);
String s = new String(chars);
回答by Bozho
StringUtils.repeat(str, count)from apache commons-lang
StringUtils.repeat(str, count)来自 apache commons-lang
回答by T.Gounelle
For the record, with Java8 you can do that with streams:
作为记录，使用 Java8，您可以使用流来做到这一点：
String p10times = IntStream.range(0, 10)
.mapToObj(x -> "p")
.collect(Collectors.joining());
But this seems somewhat overkill.
但这似乎有些矫枉过正。
回答by Mike B.
Here is an elegant, pure Java, one-line solution:
这是一个优雅的纯 Java 单行解决方案：
Java 1.5+:
Java 1.5+：
String str = new String(new char[5]).replace("String str = "p".repeat(5); // "ppppp"
", "p"); // "ppppp"
Java 11+:
Java 11+：
public static String repeat(int len, String ch) {
String s = IntStream.generate(() -> 1).limit(len).mapToObj(x -> ch).collect(Collectors.joining());
System.out.println("s " + s);
return s;
}
回答by Sohan
Bit more advance and readable ,
更先进和可读，
##代码##