源自Difference between String.Join() vs String.Concat() With .NET 4.0, String.Join() uses StringBuilder class internally so it is more efficient.Whereas String.Concat() uses basic concatenation of String using "+" which is of course not an efficie
原文发布时间为:2011-06-29 -- 来源于本人的百度文章 [由搬家工具导入] Union 会去重复后合并。而Contact不去重直接合并。 所以Contact当然比较快了。所以如果你不用去重的时候,尽量用Contact做合并吧。 在SQL里面:Union uses 'UNION' while Concat uses 'UNION ALL'. Union removes duplicates.Concat does not.
Descending Order Description: Your task is to make a function that can take any non-negative integer as a argument and return it with it's digits in descending order. Descending order means that you take the highest digit and place the next highest d
var a= new Array(new Array(1,2),new Array('b','c')); document.write(a[1][1]); 说白了,就是利用for循环定义二维数组! <script language="javascript" type="text/javascript"> function Array_2(nRow,nColumn){ var array1=new Array(); //定义一维数组 for(i=0;i&l