大约有 42,000 项符合查询结果（耗时：0.0838秒） [XML]
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...forms can get hard to read (and therefore hard to maintain). This page provides a good introduction to quoting in Bash.
Arrays ($var vs. $var[@] vs. ${var[@]})
Now for your array. According to the bash manual:
Referencing an array variable without a subscript is equivalent to referencing the a...
What is the point of Lookup?
...ic;
using System.Linq;
using System.Xml;
public class Test
{
static void Main()
{
// Just types covering some different assemblies
Type[] sampleTypes = new[] { typeof(List<>), typeof(string),
typeof(Enumerable), typeof(XmlReader) }...
Meaning of Choreographer messages in Logcat [duplicate]
...he logcat, that I'm quite sure, I haven't seen before. Does anyone have an idea about this?
5 Answers
...
What's the difference between NOT EXISTS vs. NOT IN vs. LEFT JOIN WHERE IS NULL?
...
Assuming you are avoiding nulls, they are all ways of writing an anti-join using Standard SQL.
An obvious omission is the equivalent using EXCEPT:
SELECT a FROM table1
EXCEPT
SELECT a FROM table2
Note in Oracle you need to use the MINUS oper...
Is ASCII code 7-bit or 8-bit?
...they can be classified as ASCII-compatible or not, and fixed- or variable-width. ASCII-compatible means that regardless of context, single bytes with values from 0x00 through 0x7F encode the same characters that they would in ASCII. You don't want to have anything to do with a non-ASCII-compatible...
Why is rbindlist “better” than rbind?
...get in a muddle of rownames using do.call(rbind, list(...))
see
How to avoid renaming of rows when using rbind inside do.call?
Memory efficiency
In terms of memory rbindlist is implemented in C, so is memory efficient, it uses setattr to set attributes by reference
rbind.data.frame is implemen...
float:left; vs display:inline; vs display:inline-block; vs display:table-cell;
...ing between elements. There are work-arounds to this, but none of them are ideal. (the best is simply to not have any spaces between the elements)
display:table-cell;
Another one where you'll have problems with browser compatibility. Older IEs won't work with this at all. But even for other browse...
How can I programmatically generate keypress events in C#?
...se the following method,
[DllImport("user32.dll")]
public static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, uint dwExtraInfo);
sample code is given below:
const int VK_UP = 0x26; //up key
const int VK_DOWN = 0x28; //down key
const int VK_LEFT = 0x25;
const int VK_RIGHT = 0x27;
...
What is the difference between Class Path and Build Path
...gument is a hint to the compiler what he should expect to be available/provided at runtime, since you don't build every class you use yourself (e.g. JFC, Libraries, ...). The buildpath contains both source and/or source/compiled dependencies and where to look for them.
– Johann...
How to create a density plot in matplotlib?
...you generated with R. This is because gaussian_kde tries to infer the bandwidth automatically. You can play with the bandwidth in a way by changing the function covariance_factor of the gaussian_kde class. First, here is what you get without changing that function:
However, if I use the following...