大约有 44,000 项符合查询结果(耗时:0.0445秒) [XML]
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...
what is faster: in_array or isset? [closed]
...e, you can check out the compiled version of your script:
echo isset($arr[123])
compiled vars: !0 = $arr
line # * op fetch ext return operands
-----------------------------------------------------------------------------
1 0 > ZEND_ISSET_ISEMPTY_...
What is “export default” in javascript?
...ello() {
console.log("Modul: Saying hello!");
}
export let variable = 123;
modul2.js
export function hello2() {
console.log("Module2: Saying hello for the second time!");
}
export let variable2 = 456;
modul3.js
export default function hello3() {
console.log("Module3: Saying hello...
Several ports (8005, 8080, 8009) required by Tomcat Server at localhost are already in use
...st gives me the help for the kill command.
– CoderGuy123
Jun 1 '15 at 2:18
...
Why can't variable names start with numbers?
... If it had to be numbers+alpha, then you could still do String 0x123 = "Hello World". Unless you state that variable names are "numbers+alpha that don't parse to a valid numeric designation", and that's just silly.
– eaolson
Oct 11 '09 at 3:56
...
Preferred order of writing latitude & longitude tuples in GIS services
.... For example, my hometown of Eugene, Oregon is at approximately N 44.1, W 123.1. If in maps.google.com I enter 44.1 -123.1, it goes to Eugene. If I enter -123.1 44, it tells me it can't find it. Interestingly, though, if I enter 123.1 W 44 N, it figures it out and goes to Eugene, so there is some f...
Getting parts of a URL (Regex)
...ex:
var a = document.createElement('a');
a.href = 'http://www.example.com:123/foo/bar.html?fox=trot#foo';
['href','protocol','host','hostname','port','pathname','search','hash'].forEach(function(k) {
console.log(k+':', a[k]);
});
/*//Output:
href: http://www.example.com:123/foo/bar.html?fox=t...
Cache busting via params
...
The param ?v=1.123 indicates a query string, and the browser will therefore think it is a new path from, say, ?v=1.0. Thus causing it to load from file, not from cache. As you want.
And, the browser will assume that the source will stay t...
How to remove the hash from window.location (URL) with JavaScript without page refresh?
...
This will remove the trailing hash as well.
eg: http://test.com/123#abc -> http://test.com/123
if(window.history.pushState) {
window.history.pushState('', '/', window.location.pathname)
} else {
window.location.hash = '';
}
...
How to hide the “back” button in UINavigationController?
...nswered Dec 11 '13 at 8:02
mattv123mattv123
89988 silver badges1313 bronze badges
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