如何获得Set集合指定位置的元素 如何得到hashset集合里的第n个元素
ognl \u600e\u4e48\u8bbf\u95ee set \u96c6\u5408\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\u6bd5\u8bbe\u7684\u65f6\u5019\uff0c\u6709\u4e00\u4e2a\u7279\u6b8a\u9700\u6c42\uff0c\u5c31\u662f \u8bbf\u95eeognl\u4e2d set \u96c6\u5408\u4e2d \u7b2c\u4e00\u4e2a\u5143\u7d20\u3002\u4f46\u662f\u7531\u4e8e set\u96c6\u5408 \u662f\u65e0\u5e8f\u7684\u3002\u56e0\u6b64
-------------------------------action------------------------
Set<Person set=new HashSet<person();
set.add(new Person(\u5f20\u4e091,24));
set.add(new Person(\u5f20\u4e092,22));
set.add(new Person(\u5f20\u4e093,21));
set.add(new Person(\u5f20\u4e094,20));
---------------------------------jsp--------------------------
<s:property value=set[0].name / -----------------------------------\u8fd9\u6837 \u662f\u4e0d\u80fd\u663e\u793a\u4efb\u4f55\u4fe1\u606f\u7684\u3002
\u56e0\u4e3a set\u662f \u65e0\u5e8f\u3002\u4e0d\u80fd\u50cf list\u90a3\u6837 list[1] map[key] \u90a3\u6837 \u76f4\u63a5\u8bbf\u95ee
-----------------------------------------------\u89e3\u51b3\u65b9\u6cd5----------------------------------------------------
\u5199\u4e00\u4e2a \u9759\u6001\u65b9\u6cd5\u3002\u7136\u540e\u8ba9ognl\u8c03\u7528\u663e\u793a
-------------------------------\u9759\u6001\u65b9\u6cd5--------------------
package com.shuangXing.tools;
import java.util.Iterator;
import java.util.Set;
public class ShuangXingTools {
//\u83b7\u53d6 set\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20
public static <T Object getSet(Set<T set){
Iterator it= set.iterator() ;
return it.next();}}-------------------------------jsp--------------------
<s:property [email protected]@getSet(set).name/
------------------------------\u8f93\u51fa\u7ed3\u679c-------------------
----------------------------------
hashset\u96c6\u5408\u65e0\u6cd5\u5f97\u5230\u91cc\u9762\u7684\u7b2cn\u4e2a\u5143\u7d20\u3002
PS\uff1a\u56e0\u4e3ahashset\u96c6\u5408\u662f\u65e0\u5e8f\u96c6\u5408\uff0c\u96c6\u5408\u5143\u7d20\u987a\u5e8f\u4e0d\u56fa\u5b9a\uff0c\u6240\u4ee5\u65e0\u6cd5\u6307\u5b9a\u83b7\u53d6\u7b2cn\u4e2a\u5143\u7d20\u3002
HashSet \u96c6\u5408\uff1a
HashSet \u7c7b\u662f\u4e00\u4e2a\u5b9e\u73b0 ICollection \u63a5\u53e3\u548c ICollection \u6cdb\u578b\u63a5\u53e3\u7684 set \u96c6\u5408\u3002\u4ece .NET Framework 4\u5f00\u59cb\uff0cHashSet \u7c7b\u5b9e\u73b0\u4e86 ISet \u7c7b\u3002
HashSet \u96c6\u5408\u7c7b\u578b\uff1a
UnionWith\uff1a\u5e76\u96c6\u6216 Set \u52a0\u6cd5
IntersectWith\uff1a\u4ea4\u96c6
ExceptWith\uff1aSet \u51cf\u6cd5
SymmetricExceptWith\uff1a\u4f59\u96c6
HashSet不保证顺序,
LinkedHashSet按照插入顺序,
TreeSet按照自然顺序.
如果要遍历set,要使用迭代器iterator（）
Set<String> sets = obj.keySet();
int i = 1;
for (String set : sets) {
if (i == sets.size()) {
sbSelect.append(getColumn(set, key));
} else {
sbSelect.append(getColumn(set, key) + ",");
}
where.append(getWhereClause(set, key, obj));
i++;
}
i可做判断
绛旓細{System.out.println(((ADD)it.next()).a);}}}寰闆嗗悎绫set閲屾坊鍔犳暟鎹細1銆佸畾涔変竴涓猻et瀵硅薄 Set h=new HashSet();2銆佸線set涓坊鍔犳暟鎹 h.add("1st");//寰閲屾坊鍔犱竴涓瓧绗︿覆 Set鏄渶绠鍗曠殑涓绉嶉泦鍚堛傞泦鍚堜腑鐨勫璞′笉鎸鐗瑰畾鐨鏂瑰紡鎺掑簭锛屽苟涓旀病鏈夐噸澶嶅璞°係et鎺ュ彛涓昏瀹炵幇浜嗕袱涓疄鐜扮被锛欻ash...
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绛旓細浣跨敤PYTHON閲岀殑SET銆傝蒋浠讹細Python鐨3.0鐗堟湰 鐢佃剳锛歐IN10 绯荤粺锛3.2鍏嶈垂 1銆乻et闆嗗悎涓病鏈夐噸澶嶇殑鍊笺set闆嗗悎鐨褰㈠紡涓猴細锝沬tem1锛宨tem2...}锛屽垱寤簊et锛歴 = {1锛2锛3}鎴栬卻= set()鎴栬卻= set((1,2,3))锛岄噸澶嶅厓绱犲湪set涓嚜鍔ㄨ杩囨护銆2銆佸鍔犲拰鍒犻櫎鍏冪礌set_name.add(item)锛宻et_name....
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绛旓細Set<Integer> integers = new HashSet<Integer>();if( 锛乮ntegers.contains(鍘诲垽鏂湁娌℃湁id)){ //濡傛灉娌℃湁鍒欐墽琛屽垹闄 }
绛旓細鏉ヤ釜娴嬭瘯 public static void main(String[] args){ TreeSet<String> set = new TreeSet<String>(); set.add("feilong"); set.add("long"); set.add("fei"); set.add("feifei"); for (String string : set){ System.out.println(string); } } 杈撳嚭:feif...
绛旓細set闆嗗悎鐨鐗圭偣鏃犲簭鎬с佸敮涓鎬с佸彲鍙樻с侀珮鏁堟с傛嫇灞曠煡璇嗭細1銆佹棤搴忔:Set闆嗗悎涓殑鍏冪礌娌℃湁鍏堝悗椤哄簭锛屾瘡涓厓绱犲湪闆嗗悎涓殑浣嶇疆閮芥槸闅忔満鐨勩2銆佸敮涓鎬:Set闆嗗悎涓殑鍏冪礌涓嶈兘閲嶅锛屼篃灏辨槸璇村畠浠槸鍞竴鐨勩3銆佸彲鍙樻:Set闆嗗悎鏄彲鍙樼殑锛屽彲浠ラ殢鏃舵坊鍔犳垨鍒犻櫎鍏冪礌銆4銆侀珮鏁堟:Set闆嗗悎鏄氳繃鍝堝笇琛ㄥ疄鐜扮殑锛屽洜姝...
