使用Hashtable对字符串进行碰撞

1.在一些字符串数组中，常会有重复的记录，比如手机号码，我们可以通过Hashtable来对其进行过滤




public String[] checkArray(String[] str)...{


Hashtable<String, String> hash=new Hashtable<String, String>();






for(int i=0;i<str.length;i++)...{


if(!hash.containsKey(str[i]))


hash.put(str[i], str[i]);


}




Enumeration enumeration=hash.keys();


String[] str_new=new String[hash.size()];


int i=0;






while(enumeration.hasMoreElements())...{


str_new[i]=enumeration.nextElement().toString();


i++;


}


return str_new;


}

示例：
String[] mobile={"13811071500","13811071500","13811071501","13811071503","13811071501"};
mobile=checkArray(mobile);
for(int i=0;i<mobile.length;i++)
System.out.println(mobile[i]);
输出结果为：
13811071503
13811071501
13811071500
2.A,B均为字符串数组，找出在A中存在，而在B中不存在的字符串
public String[] compareArray(String[] A,String[] B){
Hashtable<String, String> hash=new Hashtable<String, String>();
Hashtable<String, String> hash_new=new Hashtable<String, String>();

for(int i=0;i<B.length;i++)
hash.put(B[i], B[i]);

for(int i=0;i<A.length;i++){
if(!hash.containsKey(A[i]))
hash_new.put(A[i], A[i]);
}

String[] C=new String[hash_new.size()];
int i=0;
Enumeration enumeration=hash_new.keys();

while(enumeration.hasMoreElements()){
C[i]=enumeration.nextElement().toString();
i++;
}
return C;
}
示例：
String[] mobile1={"13811071500","13811071501","13811071502","13811071503","13811071504"};
String[] mobile2={"13811071500","13811071505","13811071502","13811071506","13811071504"};
String[] mobile3=compareArray(mobile1,mobile2);
for(int i=0;i<mobile3.length;i++)
System.out.println(mobile[i]);
输出结果：
13811071503
13811071501
存在的问题：
每次都是倒序，可以再对程序稍加改动，变成正序。

3.将一个字符串数组中某一个特定的字符串过滤掉




/** *//**检验一个字符串数组，若包含某一特定的字符串，则将该字符串从数组中删


除，返回剩余的字符串数组


* @param str_array 字符串数组


* @param str_remove 待删除的字符串


* @return 过滤后的字符串


*/


public String[] removeStrFromArray(String[] str_array,String




str_remove)...{


Hashtable<String, String> hash=new Hashtable<String, String>();




for(int i=0;i<str_array.length;i++)...{


if(!str_array[i].equals(str_remove))


hash.put(str_array[i], str_array[i]);


}


//生成一个新的数组


String[] str_new=new String[hash.size()];


int i=0;


Enumeration enumeration=hash.keys();




while(enumeration.hasMoreElements())...{


str_new[i]=enumeration.nextElement().toString();


i++;


}


return str_new;


}