java中,若有一个数组名为arr,如何得到该数组的长度
JAVA\u600e\u6837\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\uff1f1\u3001\u6253\u5f00Eclipse\uff0c\u65b0\u5efa\u9879\u76ee\uff0c\u5728\u9879\u76eesrc\u76ee\u5f55\u65b0\u5efa\u4e00\u4e2a\u7c7b\uff0c\u4e3a\u4e86\u66f4\u597d\u64cd\u4f5c\u6570\u7ec4\uff0cJava\u4e3a\u6570\u7ec4\u63d0\u4f9blength\u5c5e\u6027\uff0c\u7528\u6765\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\uff0c\u8bed\u6cd5\u683c\u5f0f\u5982\u4e0b\u3002
2\u3001\u521b\u5efa\u6574\u5f62\u7c7b\u578b\u53d8\u91cfarray\uff0c\u521d\u59cb\u5316\u8d4b\u503c\u4e3a{1, 2, 3, 4, 5}\uff0c\u521b\u5efa\u6574\u5f62\u7c7b\u578b\u53d8\u91cflen\uff0c\u7528\u53d8\u91cfarray\u83b7\u53d6\u53d8\u91cflen\u7684\u6570\u7ec4\u957f\u5ea6\u3002
3\u3001\u7528\u4e0b\u6807\u6765\u5f15\u7528\u6570\u7ec4\u5143\u7d20\u548c\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\uff0c\u53ef\u4ee5\u7528\u5faa\u73af\u8bed\u53e5\u6765\u8bbf\u95ee\u6570\u7ec4\u6240\u6709\u5143\u7d20\u3002
4\u3001\u4ece\u524d\u5230\u540e\u8bbf\u95ee\u6570\u7ec4\u5143\u7d20\u662f\u6570\u7ec4\u7684\u904d\u5386\uff0c\u4e5f\u662f\u8fed\u4ee3\u3002
5\u3001\u5728Java SE 5.0\u5e73\u53f0\uff0c\u589e\u52a0\u4e86\u589e\u5f3a\u578bfor\u5faa\u73af\u7684\u8bed\u6cd5\uff0c\u79f0\u4e3afor-each\u5faa\u73af\uff0c\u7528\u6765\u904d\u5386\u6570\u7ec4\u66f4\u4e3a\u5408\u9002\u3002
6\u3001\u521b\u5efa\u6574\u5f62\u7c7b\u578b\u6570\u7ec4\uff0c\u521d\u59cb\u5316\u8d4b\u503c\uff0c\u7528for-each\u5faa\u73af\uff0c\u7528\u53d8\u91cfaa\u8bbf\u95ee\u6570\u7ec4array\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u7684\u503c\u3002
byte[] phone =new byte[81]; //\u5efa\u7acb\u4e00\u4e2abyte\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u957f\u5ea6\u4e3a81
phone[i]!=0\u4e2dphone[i]! //\u6570\u7ec4\u7684\u7b2ci\u7684\u4f4d\u7f6e\u4e0d\u7b490
\u5982\uff1a
byte[] phone =new byte[81]; //\u5efa\u7acb\u4e00\u4e2abyte\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u957f\u5ea6\u4e3a81
phone[1]!=0\u4e2dphone[1]! //\u6570\u7ec4\u7b2c\u4e8c\u4e2a\u53d6\u503c\u4e0d\u7b49\u4e8e0
\u540c\u65f6\u7ed9\u697c\u4e3b\u4e3e\u4e2a\u4f8b\u5b50\uff1a
public class StudyArrary {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
byte[] phone =new byte[81]; //\u5efa\u7acb\u4e00\u4e2abyte\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u957f\u5ea6\u4e3a81
for(int a = 0; a < 81; a++)
phone[a]=(byte)a; //\u6570\u7ec4\u7684\u7b2ci\u7684\u4f4d\u7f6e\u4e0d\u7b490
for(int i = 0; i < 81; i++){
if (phone[i]!=0) {
System.out.println("phone["+i+"]\u4e0d\u7b49\u4e8e0"+",phone"+i+"\u662f"+phone[i]);
}
else
System.out.println("phone["+i+"]\u7b49\u4e8e0"+",phone"+i+"\u662f"+phone[i]);
}
}
}
试试吧
arr.length
arr.length;
arr.size();
arr.length();
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