大约有 48,000 项符合查询结果（耗时：0.0619秒） [XML]
Fastest way to replace NAs in a large data.table
I have a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
...
Mapping two integers to one, in a unique and deterministic way
Imagine two positive integers A and B. I want to combine these two into a single integer C.
18 Answers
...
Simple regular expression for a decimal with a precision of 2
What is the regular expression for a decimal with a precision of 2?
17 Answers
17
...
How can I repeat a character in Bash?
...
32 Answers
32
Active
...
How do you detect where two line segments intersect? [closed]
How do I determine whether or not two lines intersect, and if they do, at what x,y point?
27 Answers
...
How should I validate an e-mail address?
What's a good technique for validating an e-mail address (e.g. from a user input field) in Android? org.apache.commons.validator.routines.EmailValidator doesn't seem to be available. Are there any other libraries doing this which are included in Android already or would I have to use RegExp?
...
HTML5 Canvas Resize (Downscale) Image High Quality?
I use html5 canvas elements to resize images im my browser. It turns out that the quality is very low. I found this: Disable Interpolation when Scaling a <canvas> but it does not help to increase the quality.
...
Pandas groupby: How to get a union of strings
I have a dataframe like this:
8 Answers
8
...
Fastest way to check if a string matches a regexp in ruby?
What is the fastest way to check if a string matches a regular expression in Ruby?
7 Answers
...
Reverse colormap in matplotlib
I would like to know how to simply reverse the color order of a given colormap in order to use it with plot_surface.
7 Answ...