大约有 5,475 项符合查询结果（耗时：0.0254秒） [XML]
How to make a great R reproducible example
...
Example:
# sample data
DF <- data.frame(id=rep(LETTERS, each=4)[1:100], replicate(100, sample(1001, 100)), Class=sample(c("Yes", "No"), 100, TRUE))
DF is about 100 x 102. I want to sample 10 rows, and a few specific columns
reproduce(DF, cols=c("id", "X1", "X73", "Class")) # I could al...
Center image in div horizontally [duplicate]
...ide image" />
</div>
</div>
CSS
img
{
max-width: 100%;
max-height: 100%;
display: block;
margin: auto auto;
}
.outer
{
border: 1px solid #888;
width: 100px;
height: 100px;
}
.inner
{
display:table-cell;
height: 100px;
width: 100px;
...
How to get indices of a sorted array in Python
...
Something like next:
>>> myList = [1, 2, 3, 100, 5]
>>> [i[0] for i in sorted(enumerate(myList), key=lambda x:x[1])]
[0, 1, 2, 4, 3]
enumerate(myList) gives you a list containing tuples of (index, value):
[(0, 1), (1, 2), (2, 3), (3, 100), (4, 5)]
You sor...
Canvas width and height in HTML5
...fff; border:1px solid #ccc; width:400px; height:160px }
<canvas width="100" height="40"></canvas>
<p>Showing that re-drawing the same antialiased lines does not obliterate old antialiased lines.</p>
...
Pass Variables by Reference in Javascript
...rvar('test_ref_number');
test_ref_number = 5;
function Fn1 (v) { v.value = 100; }
console.log("rvar('test_ref_number');");
console.log("test_ref_number = 5;");
console.log("function Fn1 (v) { v.value = 100; }");
console.log('test_ref_number.value === 5', test_ref_number.value === 5);
console.log(" "...
Convert a matrix to a 1 dimensional array
...little benchmark, as follows:
library(microbenchmark)
x=matrix(runif(1e4),100,100) # generate a 100x100 matrix
microbenchmark(y<-as.vector(x),y<-x[1:length(x)],y<-array(x),y<-c(x),times=1e4)
The first solution uses as.vector(), the second uses the fact that a matrix is stored as a con...
How to get current date & time in MySQL?
...ange, disk_space,
network_shares,date_time) VALUES('m1','ONLINE','ONLINE','100GB','ONLINE',now() )
or
INSERT INTO servers (server_name, online_status, exchange, disk_space,
network_shares,date_time) VALUES('m1', 'ONLINE', 'ONLINE', '100GB', 'ONLINE'
,CURRENT_TIMESTAMP() )
Replace date_time wit...
Return multiple columns from pandas apply()
..._test['size'].apply(sizes))
Test result are:
Separate df.apply():
100 loops, best of 3: 1.43 ms per loop
Return Series:
100 loops, best of 3: 2.61 ms per loop
Return tuple:
1000 loops, best of 3: 819 µs per loop
...
Throwing the fattest people off of an overloaded airplane.
...items on the heap. If we assume that passengers' weights will typically be 100 lbs or more, then it's unlikely that the heap will contain more than 30 items at any time.
The worst case would be if the passengers are presented in order from lowest weight to highest. That would require that every pas...
How to use CSS to surround a number with a circle?
...div class="numberCircle">1</div>
<div class="numberCircle">100</div>
<div class="numberCircle">10000</div>
<div class="numberCircle">1000000</div>
If you need to make the content longer or shorter, all you need to do is adjust the width of the c...