Java - 将引号附加到数组中的字符串并连接数组中的字符串

Java - Append quotes to strings in an array and join strings in an array

提问by Anand

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东西。

My input would be an array as mentioned below:

我的输入将是如下所述的数组：

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

Required output should be as mentioned below:

所需的输出应如下所述：

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

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

我知道我可以遍历数组并附加引号。但如果有的话，我想要一个更清洁的解决方案。

采纳答案by Olivier Grégtheitroade

With Java 8+

使用 Java 8+

Java 8 has Collectors.joining()and its overloads. It also has String.join.

Java 8Collectors.joining()及其重载。它也有String.join。

Using a Streamand a Collector

使用一个Stream和一个Collector

With a reusable function

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(", "));

Without any reusable function

没有任何可重用的功能

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

Shortest(somewhat hackish, though)

最短的（虽然有点hackish）

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

Using String.join

使用 String.join

Very hackish. Don't use except in a method called wrapWithQuotesAndJoin.

非常黑客。不要在名为wrapWithQuotesAndJoin.

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

With older versions of Java

使用旧版本的 Java

Do yourself a favor and use a library. Guavacomes immediately to mind.

帮自己一个忙，使用图书馆。立即想到番石榴。

Using Guava

使用番石榴

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));

No libraries

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();
}

Note: all the solutions assume that listOfStringsis 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).

注意：所有解决方案都假定listOfStrings是 aList<String>而不是 a String[]。您可以将 aString[]转换为List<String>using Arrays.asList(arrayOfStrings)。您可以Stream<String>直接从String[]using 获取Arrays.stream(arrayOfString)。

回答by bas

You can create the code for this functionality yourself as well:

您也可以自己为此功能创建代码：

String output = "";

for (int i = 0; i < listOfStrings.length; i++)
{
    listOfStrings[i] = "\"" + listOfStrings[i] + "\"";
    output += listOfStrings[i] + ", ";
}

回答by Sommes

public static void main(String[] args) {
    // TODO code application logic here
    String [] listOfStrings = {"day", "campaign", "imps", "conversions"};
    String output = "";

    for (int i = 0; i < listOfStrings.length; i++) {
        output += "\"" + listOfStrings[i] + "\"";
        if (i != listOfStrings.length - 1) {
            output += ", ";
        }
    }

    System.out.println(output);
}

Output: "day", "campaign", "imps", "conversions"

输出：“day”、“campaign”、“imps”、“conversions”

回答by Himanshu Mishra

There is no method present in JDK which can do this, but you can use the Apache Commons LangsStringUtlsclass , StringUtils.join()it will work

JDK 中没有可以执行此操作的方法，但是您可以使用Apache Commons Langs StringUtls类，StringUtils.join()它会起作用

回答by Sifeng

String output = "\"" + StringUtils.join(listOfStrings , "\",\"") + "\"";

回答by John Rumpel

A more generic way would be sth. like:

更通用的方法是…… 喜欢：

private static class QuoteFunction<F> {
    char quote;

    public QuoteFunction(char quote) {
        super();
        this.quote = quote;
    }

    Function<F, String> func = new Function<F,String>() {
        @Override
        public String apply(F s) {
            return new StringBuilder(s.toString().length()+2).append(quote).append(s).append(quote).toString();
        }
    };

    public Function<F, String> getFunction() {
        return func;
    }
}

... call it via the following function

...通过以下函数调用它

public static <F> String asString(Iterable<F> lst, String delimiter, Character quote) {
    QuoteFunction<F> quoteFunc = new QuoteFunction<F>(quote);
    Joiner joiner = Joiner.on(delimiter).skipNulls();
    return joiner.join(Iterables.transform(lst, quoteFunc.getFunction()));
}

回答by Kevin Peterson

Add the quotes along with the separator and then append the quotes to the front and back.

添加引号和分隔符，然后将引号附加到前后。

"\"" + Joiner.on("\",\"").join(values) + "\""