大约有 32,000 项符合查询结果（耗时：0.0696秒） [XML]
Why is `[` better than `subset`?
...g?":
Hadley suggests the following example: suppose we want to subset and then reorder a data frame using the following functions:
scramble <- function(x) x[sample(nrow(x)), ]
subscramble <- function(x, condition) {
scramble(subset(x, condition))
}
subscramble(mtcars, cyl == 4)
This re...
Efficient evaluation of a function at every cell of a NumPy array
...
You could just vectorize the function and then apply it directly to a Numpy array each time you need it:
import numpy as np
def f(x):
return x * x + 3 * x - 2 if x > 0 else x * 5 + 8
f = np.vectorize(f) # or use a different name if you want to keep the ori...
jQuery callback on image load (even when the image is cached)
...
If the src is already set, then the event is firing in the cached case, before you even get the event handler bound. To fix this, you can loop through checking and triggering the event based off .complete, like this:
$("img").one("load", function() {
...
What does “|=” mean? (pipe equal operator)
...cks if the value of two operands are equal or not, if values are not equal then condition becomes true. e.g. (A != B) is true. where as A=!B means if B is true then A become false (and if B is false then A become true).
side note: | is not called pipe, instead its called OR, pipe is shell termin...
How do I include a newline character in a string in Delphi?
... you want to make your TLabel wrap, make sure AutoSize is set to true, and then use the following code:
label1.Caption := 'Line one'+sLineBreak+'Line two';
Works in all versions of Delphi since sLineBreak was introduced, which I believe was Delphi 6.
...
deny directory listing with htaccess
...
For showing Forbidden error then include these lines in your .htaccess file:
Options -Indexes
If we want to index our files and showing them with some information, then use:
IndexOptions -FancyIndexing
If we want for some particular extension not...
What is a tracking branch?
... pull while on one of these branches fetches all the remote references and then automatically merges in the corresponding remote branch.
When you clone a repository, it generally automatically creates a master branch that tracks origin/master. That’s why git push and git pull work out of the box ...
How to check the differences between local and github before the pull [duplicate]
...
git pull is really equivalent to running git fetch and then git merge. The git fetch updates your so-called "remote-tracking branches" - typically these are ones that look like origin/master, github/experiment, etc. that you see with git branch -r. These are like a cache of the...
Passing parameters to JavaScript files
...
1) If MYLIBRARY exists then use it or define a new object. The intent is to create a global namespace, normally I will use sub namespaces so this line helps to avoid re-defining the top level namespace. 2) Yes, it has created a singleton.
...
How can I remove the first line of a text file using bash/sed script?
...t on a file of 500,000K lines (no more than 50 chars per line). However, I then realized I was using the FreeBSD version of tail (which comes with OS X by default). When I switched to GNU tail, the tail call was 10 times faster than the sed call (and the GNU sed call, too). AaronDigulla is correct h...