大约有 47,000 项符合查询结果(耗时:0.0779秒) [XML]

https://stackoverflow.com/ques... 

Regular expression search replace in Sublime Text 2

I'm looking to do search replace with regular expressions in Sublime Text 2. The documentation on this is rather anemic. Specifically, I want to do a replace on groups, so something like converting this text: ...
https://stackoverflow.com/ques... 

SQL Logic Operator Precedence: And and Or

... 296 And has precedence over Or, so, even if a <=> a1 Or a2 Where a And b is not the same...
https://stackoverflow.com/ques... 

Meaning of numbers in “col-md-4”,“ col-xs-1”, “col-lg-2” in Bootstrap

...sm, md, lg) for now, I'll start with just the numbers... the numbers (1-12) represent a portion of the total width of any div all divs are divided into 12 columns so, col-*-6 spans 6 of 12 columns (half the width), col-*-12 spans 12 of 12 columns (the entire width), etc So, if you want two equal...
https://stackoverflow.com/ques... 

jQuery map vs. each

... 270 The each method is meant to be an immutable iterator, where as the map method can be used as a...
https://stackoverflow.com/ques... 

Time complexity of Sieve of Eratosthenes algorithm

... Your n/2 + n/3 + n/5 + … n/97 is not O(n), because the number of terms is not constant. [Edit after your edit: O(n2) is too loose an upper bound.] A loose upper-bound is n(1+1/2+1/3+1/4+1/5+1/6+…1/n) (sum of reciprocals of all n...
https://stackoverflow.com/ques... 

How to count the number of true elements in a NumPy bool array

... 265 You have multiple options. Two options are the following. numpy.sum(boolarr) numpy.count_nonz...
https://stackoverflow.com/ques... 

With bash, how can I pipe standard error into another process?

... 172 There is also process substitution. Which makes a process substitute for a file. You can send s...
https://stackoverflow.com/ques... 

Intersection of two lists in Bash

... 291 comm -12 <(ls 1) <(ls 2) ...
https://stackoverflow.com/ques... 

How to add a new row to an empty numpy array

... 237 The way to "start" the array that you want is: arr = np.empty((0,3), int) Which is an empty...
https://stackoverflow.com/ques... 

Should I use a data.frame or a matrix?

...e the choice. Also: Matrices are more memory efficient: m = matrix(1:4, 2, 2) d = as.data.frame(m) object.size(m) # 216 bytes object.size(d) # 792 bytes Matrices are a necessity if you plan to do any linear algebra-type of operations. Data frames are more convenient if you frequently refer to ...