Question

我想将“ _INC”附加到列表中的每个元素。列表内容如下：

public final static List<String> PROVIDERS = Arrays.asList("asco_genes", "pubmed_oa_genes", "wiley_journals_genes", "mms_genes", "elsevier_genes", "medline_genes",
            "asco_drugs", "pubmed_oa_drugs", "wiley_journals_drugs", "mms_drugs", "elsevier_drugs", "medline_drugs", "aaas_genes", "aaas_drugs", "aacr_genes","aacr_drugs",
            "springer_nature_genes", "springer_nature_drugs");

在编程逻辑之后，列表应如下所示：

 public final static List<String> PROVIDERS = Arrays.asList("asco_genes_INC", "pubmed_oa_genes_INC", "wiley_journals_genes_INC", "mms_genes_INC", "elsevier_genes_INC", "medline_genes_INC",
                "asco_drugs_INC", "pubmed_oa_drugs_INC", "wiley_journals_drugs_INC", "mms_drugs_INC", "elsevier_drugs_INC", "medline_drugs_INC", "aaas_genes_INC", "aaas_drugs_INC", "aacr_genes_INC","aacr_drugs_INC",
                "springer_nature_genes_INC", "springer_nature_drugs_INC");

我研究过使用字符串生成器和使用字符数组来完成任务，但是它们看起来有点复杂。我想知道java是否有任何预定义的库可以使此操作更容易。

Answer 1

Java 8+，您可以创建stream并添加"_INC"，然后将其收集到List中：

List<String> list = Stream.of("asco_genes", "pubmed_oa_genes", "wiley_journals_genes", "mms_genes", "elsevier_genes", "medline_genes",
        "asco_drugs", "pubmed_oa_drugs", "wiley_journals_drugs", "mms_drugs", "elsevier_drugs", "medline_drugs", "aaas_genes", "aaas_drugs", "aacr_genes","aacr_drugs",
        "springer_nature_genes", "springer_nature_drugs")
                          .map(e -> e + "_INC")
                          .collect(Collectors.toList());

哪个会产生：

mms_genes_INC
elsevier_genes_INC
medline_genes_INC
asco_drugs_INC
pubmed_oa_drugs_INC
wiley_journals_drugs_INC
mms_drugs_INC
elsevier_drugs_INC
medline_drugs_INC
aaas_genes_INC
aaas_drugs_INC
aacr_genes_INC
aacr_drugs_INC
springer_nature_genes_INC
springer_nature_drugs_INC

Answer 2

您实际上不需要流也不需要for循环（前提是您使用Java 8或更高版本；请使用问题中的声明）：

    PROVIDERS.replaceAll(s -> s + "_INC");

结果：

asco_genes_INC
pubmed_oa_genes_INC
wiley_journals_genes_INC
mms_genes_INC
elsevier_genes_INC
medline_genes_INC
asco_drugs_INC
pubmed_oa_drugs_INC
wiley_journals_drugs_INC
mms_drugs_INC
elsevier_drugs_INC
medline_drugs_INC
aaas_genes_INC
aaas_drugs_INC
aacr_genes_INC
aacr_drugs_INC
springer_nature_genes_INC
springer_nature_drugs_INC

Answer 3

出于完整性考虑，如果您无权访问lambda，并且如果该列表可变，并且您不想创建新列表，请替换列表中的所有元素与新的String对象：

List<String> lst = Arrays.asList(...);
int n = lst.size();
for (int i = 0; i < n; i++) { // Or lst.size() if you fear concurrent accesses
    lst.set(i, lst.get(i)+"_INC"); // Or lst.get(i).concat("_INC")
}

两个注意事项：

String是不可变的，因此您无法更改其内容
如果List实现具有随机访问权限（例如ArrayList），则不会产生运行时损失，但是对于非随机访问实现（例如LinkedList），它的运行效果欠佳。 / li>

如何在列表中每个元素的末尾附加“ _INC”（字符串）？

3 个答案: