从java中的字符串数组中选择一个随机项
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Picking a random item from an array of strings in java
提问by user3266734
I have some arrays containing Strings and I would like to select randomly an item from each array. How can I accomplish this?
我有一些包含字符串的数组，我想从每个数组中随机选择一个项目。我怎样才能做到这一点？
Here are my arrays:
这是我的数组：
static final String[] conjunction = {"and", "or", "but", "because"};
static final String[] proper_noun = {"Fred", "Jane", "Richard Nixon", "Miss America"};
static final String[] common_noun = {"man", "woman", "fish", "elephant", "unicorn"};
static final String[] determiner = {"a", "the", "every", "some"};
static final String[] adjective = {"big", "tiny", "pretty", "bald"};
static final String[] intransitive_verb = {"runs", "jumps", "talks", "sleeps"};
static final String[] transitive_verb = {"loves", "hates", "sees", "knows", "looks for", "finds"};
回答by Nigel Tufnel
Use the Random.nextInt(int)method:
使用Random.nextInt(int)方法：
final String[] proper_noun = {"Fred", "Jane", "Richard Nixon", "Miss America"};
Random random = new Random();
int index = random.nextInt(proper_noun.length);
System.out.println(proper_noun[index]);
This code is not completely safe: one time out of four it'll choose Richard Nixon.
这段代码不是完全安全的：四分之一它会选择理查德尼克松。
To quote a documentation Random.nextInt(int):
引用文档Random.nextInt(int)：
Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive)
返回一个伪随机的、均匀分布在 0（含）和指定值（不含）之间的 int 值
In your case passing an array length to the nextIntwill do the trick - you'll get the random array index in the range [0; your_array.length)
在您的情况下，将数组长度传递给nextInt将会起作用 - 您将获得范围内的随机数组索引[0; your_array.length)
回答by Martin Podval
Just use http://docs.oracle.com/javase/6/docs/api/java/util/Random.html#nextInt(int)along with the size of an array.
只需使用http://docs.oracle.com/javase/6/docs/api/java/util/Random.html#nextInt(int)以及数组的大小。
回答by Dropout
If you want to cycle through your arrays you should put them into an array. Otherwise you need to do the random pick for each one separately.
如果要循环遍历数组，则应将它们放入数组中。否则，您需要分别对每一个进行随机选择。
// I will use a list for the example
List<String[]> arrayList = new ArrayList<>();
arrayList.add(conjunction);
arrayList.add(proper_noun);
arrayList.add(common_noun);
// and so on..
// then for each of the arrays do something (pick a random element from it)
Random random = new Random();
for(Array[] currentArray : arrayList){
String chosenString = currentArray[random.nextInt(currentArray.lenght)];
System.out.println(chosenString);
}
回答by user902383
if you use Listinstead of arrays you can create simple generic method which get you random element from any list:
如果您使用List而不是数组，您可以创建简单的通用方法，从任何列表中获取随机元素：
public static <T> T getRandom(List<T> list)
{
Random random = new Random();
return list.get(random.nextInt(list.size()));
}
if you want to stay with arrays, you can still have your generic method, but it will looks bit different
如果你想继续使用数组，你仍然可以使用你的泛型方法，但它看起来会有点不同
public static <T> T getRandom(T[] list)
{
Random random = new Random();
return list[random.nextInt(list.length)];
}
