大约有 47,000 项符合查询结果（耗时：0.0586秒） [XML]
What's the difference between lapply and do.call?
I'm learning R recently and confused by two function: lapply and do.call . It seems that they're just similar to map function in Lisp. But why are there two functions with such a different name? Why doesn't R just use a function called map ?
...
Remap values in pandas column with a dict
... edited Oct 3 '18 at 8:31
Winand
1,2631717 silver badges3535 bronze badges
answered Nov 27 '13 at 19:06
DSM...
Hash collision in git
...f? Well the Moon is made up of about 1047 atoms. So if we have 10 Moons... and you randomly pick one atom on one of these moons... and then go ahead and pick a random atom on them again... then the likelihood that you'll pick the same atom twice, is the likelihood that two given git commits will hav...
Good example of livelock?
I understand what livelock is, but I was wondering if anyone had a good code-based example of it? And by code-based, I do not mean "two people trying to get past each other in a corridor". If I read that again, I'll lose my lunch.
...
How to assign from a function which returns more than one value?
...ge. It does not require a special operator but does require that the left hand side be written using list[...] like this:
library(gsubfn) # need 0.7-0 or later
list[a, b] <- functionReturningTwoValues()
If you only need the first or second component these all work too:
list[a] <- function...
Regex to validate date format dd/mm/yyyy
...2-9]\d)?\d{2})$
I tested it a bit in the link Arun provided in his answer and also here and it seems to work.
Edit February 14th 2019: I've removed a comma that was in the regex which allowed dates like 29-0,-11
share
...
Is there a MySQL option/feature to track history of changes to records?
...QL database. So when a field has been changed, the old vs new is available and the date this took place. Is there a feature or common technique to do this?
...
Best way to iterate through a Perl array
Which is the best implementation(in terms of speed and memory usage) for iterating through a Perl array? Is there any better way? ( @Array need not be retained).
...
What is the difference between procedural programming and functional programming? [closed]
I've read the Wikipedia articles for both procedural programming and functional programming , but I'm still slightly confused. Could someone boil it down to the core?
...
Why does changing the sum order returns a different result?
...gnificant digits, where each addition is performed at "infinite" precision and then rounded to the nearest representable number. Here are two sums:
1/3 + 2/3 + 2/3 = (0.3333 + 0.6667) + 0.6667
= 1.000 + 0.6667 (no rounding needed!)
= 1.667 (where 1.6667 is rounded to...