大约有 40,000 项符合查询结果（耗时：0.0301秒） [XML]
Retrieve only the queried element in an object array in MongoDB collection
... returned document to contain only the first matched shapes element:
db.test.find(
{"shapes.color": "red"},
{_id: 0, shapes: {$elemMatch: {color: "red"}}});
Returns:
{"shapes" : [{"shape": "circle", "color": "red"}]}
In 2.2 you can also do this using the $ projection operator, where...
Can I have multiple primary keys in a single table?
...y one auto column and it must be defined as a key".
DROP TABLE IF EXISTS `test`.`animals`;
CREATE TABLE `test`.`animals` (
`grp` char(30) NOT NULL,
`id` mediumint(9) NOT NULL AUTO_INCREMENT,
`name` char(30) NOT NULL,
PRIMARY KEY (`grp`,`id`)
) ENGINE=MyISAM;
INSERT INTO animals (grp,name)...
How do you get a list of the names of all files present in a directory in Node.js?
...
You can use the fs.readdir or fs.readdirSync methods.
fs.readdir
const testFolder = './tests/';
const fs = require('fs');
fs.readdir(testFolder, (err, files) => {
files.forEach(file => {
console.log(file);
});
});
fs.readdirSync
const testFolder = './tests/';
const fs = require...
How to run a python script from IDLE interactive shell?
...all(['python', 'helloworld.py', 'arg'])
Read the docs for details :-)
Tested with this basic helloworld.py:
import sys
if len(sys.argv) > 1:
print(sys.argv[1])
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“Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP
...alse';
echo ' ' . (empty($v) ? 'true' : 'false');
echo "\n";
});
Test the above snippet in the 3v4l.org online PHP editor
Although PHP does not require a variable declaration, it does recommend it in order to avoid some security vulnerabilities or bugs where one would forget to give a val...
How do you overcome the HTML form nesting limitation?
...tatement, you will be able to view the support for this feature here: html5test.com/compare/feature/form-association-form.html. IE is a write-off, most other desktop browsers seem tolerable.
– fatty
Dec 22 '13 at 3:57
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How do I check if string contains substring? [duplicate]
...an write
if (str.toLowerCase().indexOf("yes") >= 0)
Or:
if (/yes/i.test(str))
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How can query string parameters be forwarded through a proxy_pass with nginx?
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Complained how? I just tested it on nginx 1.3.4 and it worked fine for me.
– kolbyjack
Aug 24 '12 at 11:48
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How do I get a human-readable file size in bytes abbreviation using .NET?
...
using Log to solve the problem....
static String BytesToString(long byteCount)
{
string[] suf = { "B", "KB", "MB", "GB", "TB", "PB", "EB" }; //Longs run out around EB
if (byteCount == 0)
return "0" + suf[0];
long bytes = Math.Abs(byteCount);
int place ...
Set mouse focus and move cursor to end of input using jQuery
...lue (to itself) I think the cursor is getting put at the end of the input. Tested in Firefox 3 and MSIE7.
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