大约有 30,000 项符合查询结果（耗时：0.0282秒） [XML]
Grouping functions (tapply, by, aggregate) and the *apply family
...rs) that much of the functionality of the *apply family is covered by the em>x m>tremely popular plyr package, the base functions remain useful and worth knowing.
This answer is intended to act as a sort of signpost for new useRs to help direct them to the correct *apply function for their particular pr...
Print a file's last modified date in Bash
...
Note that on OS m>X m> (Mac), it's stat -f "%m%t%Sm %N" filename (see man stat em>x m>amples for more details)
– Olie
Oct 9 '14 at 23:45
...
How to copy a dictionary and only edit the copy
Can someone please em>x m>plain this to me? This doesn't make any sense to me.
20 Answers
2...
iOS UIImagePickerController result image orientation after upload
...aw image data. There's a good chance that this flag is being saved to the em>x m>if data in the uploaded jpeg image, but the program you use to view it is not honoring that flag.
To rotate the UIImage to display properly when uploaded, you can use a category like this:
UIImage+fim>x m>Orientation.h
@interf...
How to convert string to Title Case in Python?
Em>x m>ample:
9 Answers
9
...
A monad is just a monoid in the category of endofunctors, what's the problem?
...ane in Categories for the Working Mathematician, one of the foundational tem>x m>ts of Category Theory. Here it is in contem>x m>t, which is probably the best place to learn em>x m>actly what it means.
But, I'll take a stab. The original sentence is this:
All told, a monad in m>X m> is just a monoid in the category of...
One-line list comprehension: if-else variants
It's more about python list comprehension syntam>x m>. I've got a list comprehension that produces list of odd numbers of a given range:
...
Python strftime - date without leading 0?
...yphen between the % and the letter, you can remove the leading zero.
For em>x m>ample %Y/%-m/%-d.
This only works on Unim>x m> (Linum>x m>, OS m>X m>), not Windows (including Cygwin). On Windows, you would use #, e.g. %Y/%#m/%#d.
share
...
How to put a unicode character in m>X m>AML?
...
Since m>X m>AML is an m>X m>ML file format you could try the m>X m>ML character escape. So instead of writing &\u2014, you could write &#m>x m>2014; instead.
share
...
What is “point free” style (in Functional Programming)?
...mbinators and function composition [...] instead of variables.
Haskell em>x m>ample:
Conventional (you specify the arguments em>x m>plicitly):
sum (m>x m>:m>x m>s) = m>x m> + (sum m>x m>s)
sum [] = 0
Point-free (sum doesn't have any em>x m>plicit arguments - it's just a fold with + starting with 0):
sum = foldr (+) 0
Or ev...