我有一个String[],其值如下:
public static final String[] VALUES = new String[] {"AB","BC","CD","AE"};
给定字符串s,是否有一种测试VALUES是否包含s的好方法?
我有一个String[],其值如下:
public static final String[] VALUES = new String[] {"AB","BC","CD","AE"};
给定字符串s,是否有一种测试VALUES是否包含s的好方法?
当前回答
使用以下方法(在本代码中contains()方法是ArrayUtils.in()):
对象Utils.java
public class ObjectUtils {
/**
* A null safe method to detect if two objects are equal.
* @param object1
* @param object2
* @return true if either both objects are null, or equal, else returns false.
*/
public static boolean equals(Object object1, Object object2) {
return object1 == null ? object2 == null : object1.equals(object2);
}
}
阵列应用程序.java
public class ArrayUtils {
/**
* Find the index of of an object is in given array,
* starting from given inclusive index.
* @param ts Array to be searched in.
* @param t Object to be searched.
* @param start The index from where the search must start.
* @return Index of the given object in the array if it is there, else -1.
*/
public static <T> int indexOf(final T[] ts, final T t, int start) {
for (int i = start; i < ts.length; ++i)
if (ObjectUtils.equals(ts[i], t))
return i;
return -1;
}
/**
* Find the index of of an object is in given array, starting from 0;
* @param ts Array to be searched in.
* @param t Object to be searched.
* @return indexOf(ts, t, 0)
*/
public static <T> int indexOf(final T[] ts, final T t) {
return indexOf(ts, t, 0);
}
/**
* Detect if the given object is in the given array.
* @param ts Array to be searched in.
* @param t Object to be searched.
* @return If indexOf(ts, t) is greater than -1.
*/
public static <T> boolean in(final T[] ts, final T t) {
return indexOf(ts, t) > -1;
}
}
正如您在上面的代码中看到的,还有其他实用方法ObjectUtils.equals()和ArrayUtils.indexOf(),它们也在其他地方使用。
其他回答
试试看:
ArrayList<Integer> arrlist = new ArrayList<Integer>(8);
// use add() method to add elements in the list
arrlist.add(20);
arrlist.add(25);
arrlist.add(10);
arrlist.add(15);
boolean retval = arrlist.contains(10);
if (retval == true) {
System.out.println("10 is contained in the list");
}
else {
System.out.println("10 is not contained in the list");
}
ObStupidAnswer(但我认为这里有一个教训):
enum Values {
AB, BC, CD, AE
}
try {
Values.valueOf(s);
return true;
} catch (IllegalArgumentException exc) {
return false;
}
一种可能的解决方案:
import java.util.Arrays;
import java.util.List;
public class ArrayContainsElement {
public static final List<String> VALUES = Arrays.asList("AB", "BC", "CD", "AE");
public static void main(String args[]) {
if (VALUES.contains("AB")) {
System.out.println("Contains");
} else {
System.out.println("Not contains");
}
}
}
创建初始设置为false的布尔值。运行一个循环来检查数组中的每个值,并与要检查的值进行比较。如果找到匹配项,请将布尔值设置为true并停止循环。然后断言布尔值为真。
您可以直接使用Arrays.asList方法以类似的方式将其初始化为List,而不是使用快速数组初始化语法,例如:
public static final List<String> STRINGS = Arrays.asList("firstString", "secondString" ...., "lastString");
然后您可以执行(如上所述):
STRINGS.contains("the string you want to find");