大约有 47,000 项符合查询结果（耗时：0.0715秒） [XML]
Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
...
How to find the kth smallest element in the union of two sorted arrays?
This is a homework question. They say it takes O(logN + logM) where N and M are the arrays lengths.
17 Answers
...
How do I print a double value without scientific notation using Java?
I want to print a double value in Java without exponential form.
14 Answers
14
...
All falsey values in JavaScript
What are the values in JavaScript that are 'falsey' , meaning that they evaluate as false in expressions like if(value) , value ? and !value ?
...
Reset C int array to zero : the fastest way?
Assuming that we have a T myarray[100] with T = int, unsigned int, long long int or unsigned long long int, what is the fastest way to reset all its content to zero (not only for initialization but to reset the content several times in my program)? Maybe with memset?
...
How can I scale the content of an iframe?
How can I scale the content of an iframe (in my example it is an HTML page, and is not a popup) in a page of my web site?
1...
Why is XOR the default way to combine hashes?
Say you have two hashes H(A) and H(B) and you want to combine them. I've read that a good way to combine two hashes is to XOR them, e.g. XOR( H(A), H(B) ) .
...
Is it possible to change only the alpha of a rgba background colour on hover?
I have a set of <a> tags with differing rgba background colours but the same alpha. Is it possible to write a single css style that will change only the opacity of the rgba attribute?
...
How to get line count of a large file cheaply in Python?
I need to get a line count of a large file (hundreds of thousands of lines) in python. What is the most efficient way both memory- and time-wise?
...
How to initialize a two-dimensional array in Python?
I'm beginning python and I'm trying to use a two-dimensional list, that I initially fill up with the same variable in every place. I came up with this:
...