在 Java 中迭代字符串列表？
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Iterating over a List of Strings In Java?
提问by Elliot Smith
I am using OpenCSVto read data from a CSV file and am using some of the sample code from the homepage:
我正在使用OpenCSV从 CSV 文件中读取数据，并使用主页中的一些示例代码：
CSVReader reader = new CSVReader(new FileReader("stockInfo.csv"));
List myEntries = reader.readAll();
And i am now trying to loop through this list and print out each entry. But i cannot seem to figure out the code to perform this.
我现在正在尝试遍历此列表并打印出每个条目。但我似乎无法弄清楚执行此操作的代码。
Could anyone explain to me how i am supposed to do this becuase i just cant seem to work it out.
任何人都可以向我解释我应该如何做到这一点，因为我似乎无法解决。
回答by skaz
Can't you do: 1)
你不能这样做：1）
for(int i = 0; i < myEntries.size(); i++){
myEntries.get(i); // do something else here
}
or
或者
2)
2)
for(String s: myEntries)
// Do work on s here
回答by HED
Have you tried using an Iterator? It should be something like this:
您是否尝试过使用迭代器？它应该是这样的：
Iterator it = myEntries.iterator();
while(it.hasNext()){
System.out.println(it.next());
}
回答by ColinD
You should be using generics with CSVReaderif possible. readAll()actually returns a List<String[]>and not a List<String>. Then, you just need to:
CSVReader如果可能，您应该使用泛型。readAll()实际上返回 aList<String[]>而不是 a List<String>。然后，您只需要：
for (String[] row : myEntries) {
System.out.println(Arrays.toString(row));
}
回答by kaliatech
Assuming you want to output each entry of each line to it's own line:
假设您想将每行的每个条目输出到它自己的行：
List<String[]> myEntries = reader.readAll();
for (String[] lineTokens : myEntries) {
for (String token : lineTokens) {
System.out.println(token);
}
}
回答by Buhake Sindi
You can do something of this effect. I've added synchronization on iterator.
你可以做一些这种效果。我在迭代器上添加了同步。
List<String[]> myEntries = reader.readAll();
Iterator<String[]> iter = myEntries.iterator();
synchronized (iter) {
while (iter.hasNext()) {
String[] items = iter.next();
for (String item: items) { //foreach loop
//Work with `item`
}
}
}
回答by Peter Szanto
In Java 8 and above you can also do
在 Java 8 及更高版本中，您还可以执行
List<String> s = new LinkedList<>();
s.stream().forEach(System.out::print);
or
或者
List<String> s = new LinkedList<>();
s.stream().forEach(s ->
System.out.print(s)
);
It is possible to use paralleStream() instead or stream() to make parallel execution. There are a lot of articles on the internet about which will execute quicker and the answer is : "it depends" (mostly on the number of items in the list)
可以使用 paralleStream() 或 stream() 来进行并行执行。互联网上有很多关于执行速度更快的文章，答案是：“这取决于”（主要取决于列表中的项目数量）
