大约有 45,000 项符合查询结果（耗时：0.0443秒） [XML]
How to chain scope queries with OR instead of AND?
...
and just for safety's sake, it's worth expressing this as Person.where("name = ? OR lastname = ?", 'John', 'Smith')
– CambridgeMike
Nov 9 '11 at 3:55
...
Why does C++ need a separate header file?
...ile with the same functions as in the .cpp file. It makes creating classes and refactoring them very difficult, and it adds unnecessary files to the project. And then there is the problem with having to include header files, but having to explicitly check if it has already been included.
...
Check for installed packages before running install.packages() [duplicate]
... computers. One of its lines contains the install.packages("xtable") command.
16 Answers
...
What is the purpose of the “Prefer 32-bit” setting in Visual Studio and how does it actually work?
...
Microsoft has a blog entry What AnyCPU Really Means As Of .NET 4.5 and Visual Studio 11:
In .NET 4.5 and Visual Studio 11 the cheese has been moved. The
default for most .NET projects is again AnyCPU, but there is more than
one meaning to AnyCPU now. There is an additional sub-type o...
Avoid browser popup blockers
I'm developing an OAuth authentication flow purely in JavaScript and I want to show the user the "grant access" window in a popup, but it gets blocked.
...
Simple state machine example in C#?
...is simple state diagram:
We have:
4 states (Inactive, Active, Paused, and Exited)
5 types of state transitions (Begin Command, End Command, Pause Command, Resume Command, Exit Command).
You can convert this to C# in a handful of ways, such as performing a switch statement on the current state...
How to sort a HashSet?
...ements sorted for this one occurrence, then just temporarily create a List and sort that:
Set<?> yourHashSet = new HashSet<>();
...
List<?> sortedList = new ArrayList<>(yourHashSet);
Collections.sort(sortedList);
...
How to Create a circular progressbar in Android which rotates on it?
... creating a layer-list, I separated it into two files. One for ProgressBar and one for its background.
This is the ProgressDrawable file (@drawable folder): circular_progress_bar.xml
<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
...
Standard deviation of a list
I want to find mean and standard deviation of 1st, 2nd,... digits of several (Z) lists. For example, I have
8 Answers
...
How to remove an element from a list by index
...
Use del and specify the index of the element you want to delete:
>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]
Also supports slices:
>>> del a[2:4]
>...