大约有 41,200 项符合查询结果(耗时:0.0446秒) [XML]

https://stackoverflow.com/ques... 

Fast permutation -> number -> permutation mapping algorithms

I have n elements. For the sake of an example, let's say, 7 elements, 1234567. I know there are 7! = 5040 permutations possible of these 7 elements. ...
https://stackoverflow.com/ques... 

Preferred way to create a Scala list

...end is O(1). – Daniel C. Sobral Aug 31 '15 at 19:33 @pgoggijr That is not true. First, there's no "change" anywhere, b...
https://stackoverflow.com/ques... 

Getting a map() to return a list in Python 3.x

... Do this: list(map(chr,[66,53,0,94])) In Python 3+, many processes that iterate over iterables return iterators themselves. In most cases, this ends up saving memory, and should make things go faster. If all you're going to do is iterate over thi...
https://stackoverflow.com/ques... 

How to extract a floating number from a string [duplicate]

I have a number of strings similar to Current Level: 13.4 db. and I would like to extract just the floating point number. I say floating and not decimal as it's sometimes whole. Can RegEx do this or is there a better way? ...
https://stackoverflow.com/ques... 

How to get one value at a time from a generator function in Python?

... answered Mar 10 '10 at 19:13 Ignacio Vazquez-AbramsIgnacio Vazquez-Abrams 668k127127 gold badges11911191 silver badges12501250 bronze badges ...
https://stackoverflow.com/ques... 

Regex to remove all (non numeric OR period)

I need for text like "joe ($3,004.50)" to be filtered down to 3004.50 but am terrible at regex and can't find a suitable solution. So only numbers and periods should stay - everything else filtered. I use C# and VS.net 2008 framework 3.5 ...
https://stackoverflow.com/ques... 

how to solve “ruby installation is missing psych” error?

I used rvm to install ruby 1.9.3. even though it was successfully installed, it complained about libyaml. and now every time i wanna install a gem (say rails) this warning shows up: ...
https://stackoverflow.com/ques... 

Rails 3 datatypes?

Where can I find a list of data types that can be used in rails 3? (such as text, string, integer, float, date, etc.?) I keep randomly learning about new ones, but I'd love to have a list I could easily refer to. ...
https://stackoverflow.com/ques... 

Comparing two dictionaries and checking how many (key, value) pairs are equal

... | edited Jun 14 '18 at 13:15 Olivier Melançon 17.9k33 gold badges3232 silver badges5555 bronze badges ...