{"id":597,"date":"2008-04-24T22:47:45","date_gmt":"2008-04-24T14:47:45","guid":{"rendered":"http:\/\/blog.smallken.ink\/2008\/04\/24\/java\/597.html"},"modified":"2008-04-24T22:49:03","modified_gmt":"2008-04-24T14:49:03","slug":"%e8%85%a6%e5%8a%9b%e6%bf%80%e7%9b%aa%e7%8e%a9%e4%b8%80%e4%b8%8bjdk50%e7%9a%84%e6%96%b0%e8%aa%9e%e6%b3%95-foreach","status":"publish","type":"post","link":"https:\/\/blog.smallken.site\/?p=597","title":{"rendered":"\u8166\u529b\u6fc0\u76ea\u73a9\u4e00\u4e0bJDK5.0\u7684\u65b0\u8a9e\u6cd5 – foreach"},"content":{"rendered":"

\u6700\u8fd1\u516c\u53f8\u5167\u8a13 java\uff0c\u8001\u5e2b\u7d66\u6211\u5011\u7684\u4e00\u984cforeach\u7684\u4f5c\u696d\uff0c\u7b2c\u4e00\u6b21\u770b\u5230\u89ba\u5f97\u883b\u65b0\u9bae\u7684\uff0c\u6211\u4f86\u4ecb\u7d39\u4e00\u4e0b\u3002<\/p>\n

foreach \u662f java JDK5.0\u4ee5\u5f8c\u624d\u6709\u65b0\u8a9e\u6cd5\uff0c\u9019\u7a2e\u8a9e\u6cd5Compiler\u771f\u6b63\u5728\u7de8\u8b6f\u6642\u9084\u6703\u6539\u6210\u539f\u59cb\u7684\u8a9e\u6cd5\uff0c\u9019\u7a2e\u60c5\u6cc1\u4fd7\u7a31”Compiler Sugar”\u3002<\/p>\n

\u5148\u770b\u4e00\u6bb5 foreach \u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n

public class Test2 { <\/font><\/p>\n

public static void main(String[] args) { <\/font> <\/p>\n

        int [] a = {0,1,2,3,4,5,6,7,8,9};
        for(int i : a)
            System.out.print(a[i] + ” “);
        } <\/font> <\/p>\n

}<\/font> <\/p>\n

a \u662f\u4e00\u7dad\u9663\u5217\uff0cfor() \u88e1\u9762\u7528\u5192\u865f\u5206\u9694\uff0c\u9019\u8a9e\u6cd5\u6703\u81ea\u52d5\u5c07 a \u9663\u5217\u4e2d\u7684\u5143\u7d20\u4f9d\u4f9d\u63d0\u51fa\u4f86\uff0c\u7528 int i \u4f86\u63a5\u6bcf\u500b\u5143\u7d20\u5167\u5bb9\uff0c\u6240\u4ee5\u5370\u51fa\u4f86\u7d50\u679c\u5982\u4e0b\u3002
0 1 2 3 4 5 6 7 8 9 <\/p>\n

  <\/p>\n

\u984c\u76ee\u662f\u4e09\u7dad\u9663\u5217 <\/p>\n

public class Test1 {
    public static void main(String[] args) {
        <\/font><\/p>\n

  <\/font>    \/\/ \u4e09\u7dad\u9663\u5217\uff0c\u4f9d\u4f9d\u586b\u5165\u6578\u503c<\/font>
<\/font>      int[][][] a = new int[10][10][10];
        for(int i = 0; i<a.length; i++) {
            for(int j=0; j<a[i].length; j++) {
                for(int k=0; k<a[i][j].length; k++) {
                    a[i][j][k] = 100*i+10*j+k;
                }
            }
        }<\/p>\n

   <\/font>\/\/ a \u9663\u5217\u88e1\u9762\u586b\u4ec0\u9ebc\u503c\u4e0d\u9700\u8981\u7ba1\uff0c\u4e0b\u9762\u662f\u50b3\u7d71 for loop \u4f5c\u6cd5\u628a\u5168\u90e8\u503c\u5217\u5370\u51fa\u4f86
<\/font>   for(int i = 0; i<a.length; i++) {
            for(int j=0; j<a[i].length; j++) {
                for(int k=0; k<a[i][j].length; k++) {
                    System.out.print(a[i][j][k]+” “);
                }               
            }
     }
\u3000\/* \u984c\u76ee\u662f\u5982\u4f55\u5c07\u4e0a\u982d\u5217\u5370 a \u4e09\u7dad\u9663\u5217\u7684\u503c\uff0c\u8a9e\u6cd5\u7528 foreach \u6539\u5beb?
       \u8a9e\u6cd5\u6703\u5dee\u4e0d\u591a\u662f\u9577\u9019\u6a23
<\/font>       for(  :  ) {
            for(  :  ){
                for( :  ) {
                    System.out.print( + ” “);
                }               
            }       
         }<\/font><\/p>\n

    *\/<\/font><\/p>\n

\u4e00\u4e0b\u9801\u770b\u89e3\u7b54<\/font><\/p>\n

<\/p>\n

\u7b54\u6848\u662f:<\/font><\/p>\n

for(int [][] i:  a) {
    for(int [] j : i ){
        for(int k: j ) {
            System.out.print(k+ ” “);
        }
    }
}<\/font><\/p>\n

\u8aaa\u660e\uff1a\u5f9e\u6700\u5916\u5c64\u7684 for \u8ff4\u5708\u958b\u59cb\u770b\uff0ca[][][]\u662f\u4e00\u500b\u4e09\u7dad\u7684\u9663\u5217\uff0c\u4ee5\u9019\u984c\u4f86\u8b1b\u6bcf\u7dad\u90fd\u670910\u500b\u5143\u7d20\uff0c\u9019\u96b1\u542b\u8457\u9019\u4e09\u7dad\u9663\u5217\u662f\u753110\u500b\u4e8c\u7dad\u9663\u5217\u7d44\u6210\u7684<\/font>\uff0c\u6240\u4ee5\u6700\u5916\u5c64\u7684 for( : ) \u5192\u865f\u7684\u53f3\u908a\u662f\u4e09\u7dad\u9663\u5217\u7684 a[][][]\uff0c\u5de6\u908a\u5c31\u61c9\u8a72\u8981\u662f\u4e8c\u7dad\u9663\u5217\u7684 int [][] i\u53bb\u63a5\uff0c\u63a5\u8457\u518d\u770b\u7b2c\u4e8c\u5c64 for\uff0c\u7b2c\u4e8c\u5c64\u7684 for \u8981\u8655\u7406\u7684\u662f\u4e8c\u7dad\u9663\u5217\u7684 i [][]\uff0c\u4e00\u6a23\u7684\u9053\u7406\u6bcf\u7dad\u90fd\u670910\u500b\u5143\u7d20\uff0c\u4e5f\u96b1\u542b\u8457 i[][] \u662f\u753110\u500b\u4e00\u7dad\u9663\u5217\u6240\u7d44\u6210\u7684\uff0cfor( : )\u5192\u865f\u7684\u53f3\u908a\u662f\u4e8c\u7dad\u9663\u5217\u7684 i [][] \u7684\u8a71\uff0c\u5192\u865f\u5de6\u908a\u61c9\u8a72\u662f\u8981\u4e00\u500b\u4e00\u7dad\u9663\u5217\u53bb\u63a5\u5427\uff0c\u9019\u88e1\u5c31\u7528\u4e86 int [] j \u53bb\u63a5\uff0c\u5230\u4e86\u6700\u88e1\u9762\u7684\u7b2c\u4e09\u5c64 for\uff0cj [] \u662f\u4e00\u7dad\u9663\u5217\uff0c\u5927\u5bb6\u5c0d\u4e00\u7dad\u9663\u5217\u6700\u719f\u6089\u4e0d\u904e\u7684\u4e86\uff0c\u9019\u88e1\u540c\u6a23\u4e00\u7dad\u670910\u500b\u5143\u7d20\uff0c\u6bcf\u500b\u5143\u7d20\u5c31\u7528 int k \u53bb\u63a5\u5b83\u7684\u503c\uff0c\u6240\u4ee5 k \u5df2\u7d93\u662f\u771f\u6b63\u7684\u503c\u4e86\u5594\uff0c\u6240\u4ee5\u4f9d\u4f9d\u628a k \u5370\u51fa\u4f86\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n

\u5176\u5be6\u9019\u500b \u4f8b\u5b50\u7528\u4e86\u4e09\u7dad\u9663\u5217\uff0c\u6bcf\u7dad\u9663\u5217\u90fd\u662f10\uff0c\u4f46\u662f\u5176\u5be6 foreach \u6700\u5927\u7684\u597d\u8655\u5c31\u662f\u4e0d\u7528\u53bb\u7ba1\u9663\u5217\u6bcf\u4e00\u7dad\u7684\u9577\u5ea6\uff0c\u5c31\u7b97\u662f 10X20X30\u7684\u9663\u5217\uff0c\u9019\u6a23\u7684\u5beb\u6cd5\u7167\u6a23\u4e5f\u884c\u5f97\u901a\u3002<\/p>\n

\u90a3 foreach \u4e5f\u6709\u58de\u8655\uff0c\u58de\u8655\u5c31\u662f\u770b\u4e0d\u7fd2\u6163\u5427\uff0c\u5f8c\u4eba\u7dad\u8b77\u4f60\u7684\u7a0b\u5f0f\u78bc\u6703\u6bd4\u8f03\u8f9b\u82e6\uff0c\u9019\u7a2e\u8a9e\u6cd5\u81ea\u5df1\u73a9\u53ef\u4ee5\uff0c\u5408\u4f5c\u578b\u7684\u958b\u767c\u6848\u6700\u597d\u9084\u662f\u4ee5\u50b3\u7d71\u719f\u6089\u7684\u8a9e\u6cd5\uff0c\u770b\u5f97\u6bd4\u8f03\u61c2\u7684\u8a9e\u6cd5\u70ba\u4e3b\u5566\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u6700\u8fd1\u516c\u53f8\u5167\u8a13 java\uff0c\u8001\u5e2b\u7d66\u6211\u5011\u7684\u4e00\u984cforeach\u7684\u4f5c\u696d\uff0c\u7b2c\u4e00\u6b21\u770b\u5230\u89ba\u5f97\u883b\u65b0\u9bae\u7684\uff0c\u6211\u4f86\u4ecb\u7d39\u4e00\u4e0b\u3002 fore…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-597","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"https:\/\/blog.smallken.site\/index.php?rest_route=\/wp\/v2\/posts\/597","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.smallken.site\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.smallken.site\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.smallken.site\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.smallken.site\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=597"}],"version-history":[{"count":0,"href":"https:\/\/blog.smallken.site\/index.php?rest_route=\/wp\/v2\/posts\/597\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.smallken.site\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=597"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.smallken.site\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=597"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.smallken.site\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=597"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}