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How do you round a floating point number in Perl?
.... For rounding to a certain number of digits, sprintf() or printf() is usually the easiest
route.
printf("%.3f", 3.1415926535); # prints 3.142
The POSIX module (part of the standard Perl distribution) implements
ceil(), floor(), and a number of other mathematical and trigonometric
func...
Simple Digit Recognition OCR in OpenCV-Python
...stand some of the features at end)
2) Since I knew, without understanding all those features, it is difficult to do that method. I tried some other papers, but all were a little difficult for a beginner.
So I just decided to take all the pixel values as my features. (I was not worried about accura...
Preferred way to create a Scala list
...do so with a tail-recursive function, foldLeft, or something else is not really relevant.
If you get the elements in the same order you use them, then a ListBuffer is most likely a preferable choice, if performance is critical.
But, if you are not on a critical path and the input is low enough, yo...
How to filter a dictionary according to an arbitrary condition function?
...
And here is a good explanation why the function call dict() is slower than the constructor/literal syntax {} doughellmann.com/2012/11/…
– dorvak
Jul 10 '13 at 9:37
...
iOS开发过程中的各种tips - 更多技术 - 清泛网 - 专注C/C++及内核技术
...直接在介绍AFNetworking的时候详解吧。
25.使用NSURLConnection下载数据
1. 创建对象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]];
[NSURLConnection connectionWithRequest:request delegate:self];
2. NSURLCon...
How do I provide custom cast support for my class?
...ou want users to have to cast it or whether you want it to happen automagically. Generally, one direction will always work, that's where you use implicit, and the other direction can sometimes fail, that's where you use explicit.
The syntax is like this:
public static implicit operator dbInt64(Byt...
Finding quaternion representing the rotation from one vector to another
...
Be aware that this does not handle the case of parallel vectors (both in the same direction or pointing in opposite directions). crossproduct will not be valid in these cases, so you first need to check dot(v1, v2) > 0.999999 and dot(v1, v2) < -0.999999, respectively, ...
Asynchronous method call in Python?
I was wondering if there's any library for asynchronous method calls in Python . It would be great if you could do something like
...
How to pretty print nested dictionaries?
...
This is cool, but doesn't print all dictionaries well. print json.dumps(myObject.__dict__, sort_keys=True, indent=4) #TypeError: <object at 0x0000000002E6A748> is not JSON serializable
– tponthieux
Feb 8 '12 at 2...
How to avoid annoying error “declared and not used”
...s it easier to read code written by other people (you are always sure that all declared variables will be used), and avoid some possible dead code.
But, if you really want to skip this error, you can use the blank identifier (_) :
package main
import (
"fmt" // imported and not used: "fmt"
)
...