我有一个perl脚本,它可以很好地打印到屏幕上,但是当我试图将输出重定向到csv文件时,会得到以下错误:Expected fields to an array ref。我使用的是Text::CSV_XS,给出错误的行是$csv->print ($fh, $_) for @rows;
#!/user/local/bin/perl
use Text::CSV_XS;
$|=1;
sub main {
print "Enter file to process: ";
my $file = <STDIN>;
chomp $file;
我正在尝试理解这段JavaScript代码
var arr = [[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]];
var main = [];
var long;
for(var i=0; i<arr.length; i++){
long = arr[i][0]; //setting the long var first element of array
for(var j=0; j<arr.length; j++){
//comparing fir
如何在集合中添加一个在MongoDB中积累值集合字段的文档?
我有一个MongoDB集合,其文档格式如下:
{
"_id" : 3876435465554,
"title" : "xxx",
"category" : "xxx",
...
}
因此,愿望的结果是:
{ "_id" : "All", "num" : 28 } // <- This is the document that I want include in the output