大约有 40,000 项符合查询结果（耗时：0.0547秒） [XML]
Efficient SQL test query or validation query that will work across all (or most) databases
...for idleness. For example, the JDBC pooling library c3p0 has a property called preferredTestQuery , which gets executed on the connection at configured intervals. Similarly, Apache Commons DBCP has validationQuery .
...
Trimming a huge (3.5 GB) csv file to read into R
... expert at this, but you might consider trying MapReduce, which would basically mean taking a "divide and conquer" approach. R has several options for this, including:
mapReduce (pure R)
RHIPE (which uses Hadoop); see example 6.2.2 in the documentation for an example of subsetting files
Alterna...
How to pass a function as a parameter in Java? [duplicate]
...u have a class or interface with only a single abstract method (sometimes called a SAM type), for example:
public interface MyInterface {
String doSomething(int param1, String param2);
}
then anywhere where MyInterface is used, you can substitute a lambda expression:
class MyClass {
publ...
How to generate all permutations of a list?
How do you generate all the permutations of a list in Python, independently of the type of elements in that list?
33 Answer...
std::shared_ptr thread safety explained
...ly regarding your original 3 questions.
But the ending part of your edit
Calling reset() in thread IV will delete previous instance of A class created in first thread and replace it with new instance? Moreover after calling reset() in IV thread other threads will see only newly created object?
is ...
Using multiple delimiters in awk
...n the input field separator.
See another example:
$ cat file
hello#how_are_you
i#am_very#well_thank#you
This file has two fields separators, # and _. If we want to print the second field regardless of the separator being one or the other, let's make both be separators!
$ awk -F"#|_" '{print ...
Location Services not working in iOS 8
... check whether the user is running iOS 8 or iOS 7. For example:
#define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
//In ViewDidLoad
if(IS_OS_8_OR_LATER) {
[self.locationManager requestAlwaysAuthorization];
}
[self.locationManager startUpdatingLocation];
...
map function for objects (instead of arrays)
... of obj1 sit on the 'prototype' of obj2
console.log(obj2) // Prints: obj2.__proto__ = { 'a': 1, 'b': 2, 'c': 3}
console.log(Object.keys(obj2)); // Prints: an empty Array.
for (key in obj2) {
console.log(key); // Prints: 'a', 'b', 'c'
}
jsbin
However, please do me a favor and av...
What is the difference between Cygwin and MinGW?
...Unix-based applications to Windows much easier, by emulating many of the small details that Unix-based operating systems provide, and are documented by the POSIX standards. Your application can use Unix feature such as pipes, Unix-style file and directory access, and so forth, and it can be compile...
How to set cornerRadius for only top-left and top-right corner of a UIView?
...WillLayoutSubviews() {
super.viewWillLayoutSubviews()
// Call the roundCorners() func right there.
theView.roundCorners(corners: [.topLeft, .topRight], radius: 30)
}
}
share
|
...