大约有 40,000 项符合查询结果（耗时：0.0343秒） [XML]
sed: print only matching group
...it with a 2nd grep.
# To extract \1 from /xx([0-9]+)yy/
$ echo "aa678bb xx123yy xx4yy aa42 aa9bb" | grep -Eo 'xx[0-9]+yy' | grep -Eo '[0-9]+'
123
4
# To extract \1 from /a([0-9]+)b/
$ echo "aa678bb xx123yy xx4yy aa42 aa9bb" | grep -Eo 'a[0-9]+b' | grep -Eo '[0-9]+'
678
9
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Difference between “change” and “input” event for an `input` element
... answered Aug 25 at 17:57
zcoop98zcoop98
81333 silver badges1717 bronze badges
...
Remove duplicated rows using dplyr
...ction for this purpose.
Original answer below:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_nu...
Simplest way to detect a mobile device in PHP
...i|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i',substr($useragent,0,4)))
header('Location: http://detectmobilebrowser.com/mobile');
?>
...
How can I measure the speed of code written in PHP? [closed]
...answered Oct 15 '15 at 15:18
na-98na-98
85188 silver badges1313 bronze badges
...
module.exports vs exports in Node.js
...:
var x = require('file1.js');
contents of file1.js:
module.exports = '123';
When the above statement is executed, a Module object is created. Its constructor function is:
function Module(id, parent) {
this.id = id;
this.exports = {};
this.parent = parent;
if (parent &&...
Generic TryParse
... it's simply a matter of calling thusly:
var value = TryParse<int>("123", int.TryParse);
var value2 = TryParse<decimal>("123.123", decimal.TryParse);
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...
Can a relative sitemap url be used in a robots.txt?
...nswered Aug 23 '19 at 6:30
cstpl123cstpl123
1722 bronze badges
add a c...
蓝牙BLE硬件接入及IO控制 · App Inventor 2 源码商店
...IO控制功能，不提供技术支持。配套的文档：https://www.fun123.cn/reference/iot/ble.html 源码购买 ￥3.8 ...
A regular expression to exclude a word/string
...ropagate the query string too? So if someone visits mydomain.com/hello?abc=123 I'd like it to rewrite to mydomain.com/Profile.aspx?id=hello&abc=123 I'm also a bit unsure about the performance of (.+) at the end to capture the querystring in the original request.
– romiem
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