Java - 将引号附加到数组中的字符串并连接数组中的字符串 [英] Java - Append quotes to strings in an array and join strings in an array

问题描述

我想将双引号附加到数组中的字符串，然后将它们作为单个字符串加入(保留引号).是否有任何字符串库可以做到这一点?我已经尝试过 Apache commons StringUtils.join 和 Google guava 中的 Joiner 类，但找不到任何附加双引号的内容.

I would like to append double quotes to strings in an array and then later join them as a single string (retaining the quotes). Is there any String library which does this? I have tried Apache commons StringUtils.join and the Joiner class in Google guava but couldn't find anything that appends double quotes.

我的输入将是如下所述的数组:

My input would be an array as mentioned below:

String [] listOfStrings = {"day", "campaign", "imps", "conversions"};

所需的输出应如下所述:

Required output should be as mentioned below:

String output = "\"day\", \"campaign\", \"imps\", \"conversions\"";

我知道我可以遍历数组并附加引号.但如果有的话，我想要一个更简洁的解决方案.

I know I can loop through the array and append quotes. But I would like a more cleaner solution if there is one.

推荐答案

使用 Java 8+

Java 8 具有 Collectors.joining() 及其重载.它还有 String.join.

具有可重复使用的功能

Function<String,String> addQuotes = s -> "\"" + s + "\"";

String result = listOfStrings.stream()
  .map(addQuotes)
  .collect(Collectors.joining(", "));

没有任何可重用的功能

String result = listOfStrings.stream()
  .map(s -> "\"" + s + "\"")
  .collect(Collectors.joining(", "));

最短的(虽然有点hackish)

Shortest (somewhat hackish, though)

String result = listOfStrings.stream()
  .collect(Collectors.joining("\", \"", "\"", "\""));

使用String.join

非常黑客.不要在名为 wrapWithQuotesAndJoin 的方法中使用.

String result = listOfString.isEmpty() ? "" : "\"" + String.join("\", \"", listOfStrings) + "\"";

使用旧版本的 Java

帮自己一个忙，使用图书馆.Guava立刻浮现在脑海中.

Function<String,String> addQuotes = new Function<String,String>() {
  @Override public String apply(String s) {
    return new StringBuilder(s.length()+2).append('"').append(s).append('"').toString();
  }
};
String result = Joiner.on(", ").join(Iterables.transform(listOfStrings, addQuotes));

没有图书馆

String result;
if (listOfStrings.isEmpty()) {
  result = "";
} else {
  StringBuilder sb = new StringBuilder();
  Iterator<String> it = listOfStrings.iterator();
  sb.append('"').append(it.next()).append('"'); // Not empty
  while (it.hasNext()) {
    sb.append(", \"").append(it.next()).append('"');
  }
  result = sb.toString();
}

注意:所有的解决方案都假设 listOfStrings 是一个 List 而不是 String[]>.您可以使用 Arrays.asList(arrayOfStrings) 将 String[] 转换为 List.您可以使用 Arrays.stream(arrayOfString) 直接从 String[] 获取 Stream.

Note: all the solutions assume that listOfStrings is a List<String> rather than a String[]. You can convert a String[] into a List<String> using Arrays.asList(arrayOfStrings). You can get a Stream<String> directly from a String[] using Arrays.stream(arrayOfString).

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