大约有 46,000 项符合查询结果（耗时：0.0697秒） [XML]
What are bitwise shift (bit-shift) operators and how do they work?
...
The bit shifting operators do exactly what their name implies. They shift bits. Here's a brief (or not-so-brief) introduction to the different shift operators.
The Operators
>> is the arithmetic (or signed) right shift o...
How to find first element of array matching a boolean condition in JavaScript?
.../elegant way to find the first element of a JS array matching a given condition. A C# equivalent would be List.Find .
12 ...
Direct casting vs 'as' operator?
...to s if o is not a string or if o is null. For this reason, you cannot use it with value types (the operator could never return null in that case). Otherwise, assigns o to s.
string s = o.ToString(); // 3
Causes a NullReferenceException if o is null. Assigns whatever o.ToString() returns to s, no...
Bad value X-UA-Compatible for attribute http-equiv on element meta
...
Either X-UA-Compatible is not "standard" HTML (FSVO "standard" that involves appearing on a publicly editable wiki page referenced by the specification) or the Validator isn't up to date with the current status of that wiki.
...
Entity Framework Code First - two Foreign Keys from same table
...OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Match>()
.HasRequired(m => m.HomeTeam)
.WithMany(t => t.HomeMatches)
.HasForeignKey(m => m.HomeTeamId)
.WillCascadeOnDelete(fa...
How can I call controller/view helper methods from the console in Ruby on Rails?
When I load script/console , sometimes I want to play with the output of a controller or a view helper method.
14 Answers
...
NSUserDefaults - How to tell if a key exists
...small iPhone app, and I am using NSUserDefaults as my data persistence. It only has to keep track of a few things, such as some names and some numbers so I figure I might as well keep it simple.
...
Easiest way to toggle 2 classes in jQuery
If I have class .A and class .B and want to switch in between on button click, what's a nice solution for that in jQuery? I still don't understand how toggleClass() works.
...
Why does pattern matching in Scala not work with variables?
...
What you're looking for is a stable identifier. In Scala, these must either start with an uppercase letter, or be surrounded by backticks.
Both of these would be solutions to your problem:
def mMatch(s: String) = {
val target: String = "a"
s match {
case `target` => println...
difference between primary key and unique key
...
Primary Key:
There can only be one primary key in a table
In some DBMS it cannot be NULL - e.g. MySQL adds NOT NULL
Primary Key is a unique key identifier of the record
Unique Key:
Can be more than one unique key in one table
Unique key can have NULL values
It can be a candidate key
Unique k...