大约有 40,000 项符合查询结果（耗时：0.0490秒） [XML]
Repeat each row of data.frame the number of times specified in a column
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Great! I always forget you can use square brackets that way. I keep thinking of indexing just for subsetting or reordering. I had another solution that is far less elegant and no doubt less efficient. I might post anyway so that others can co...
Working with huge files in VIM
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I had a 12GB file to edit today. The vim LargeFile plugin did not work for me. It still used up all my memory and then printed an error message :-(. I could not use hexedit for either, as it cannot insert anything, just overwrite. Here is an alternative approach:
You split the file, edit th...
Attempted to read or write protected memory. This is often an indication that other memory is corrup
...ping someone can enlighten me as to what could possibly be causing this error:
26 Answers
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What is the difference between & and && in Java?
I always thought that && operator in Java is used for verifying whether both its boolean operands are true , and the & operator is used to do Bit-wise operations on two integer types.
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In C# check that filename is *possibly* valid (not that it exists) [duplicate]
...entException) { }
catch (System.IO.PathTooLongException) { }
catch (NotSupportedException) { }
if (ReferenceEquals(fi, null)) {
// file name is not valid
} else {
// file name is valid... May check for existence by calling fi.Exists.
}
For creating a FileInfo instance the file does not need to...
What is difference between instantiating an object using new vs. without
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By contrast:
Time* t = new Time(12, 0, 0);
... allocates a block of memory by calling either ::operator new() or Time::operator new(), and subsequently calls Time::Time() with this set to an address within that memory block (and also returned as the result of new), which is then stored in t. As ...
Switching to landscape mode in Android Emulator
... after a couple hours of searching the documentation and Google. I set the orientation of my Android app to landscape in the AndroidManifest.xml file:
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Allow user to select camera or gallery for image
...d to query the PackageManager with PackageManager.queryIntentActivities() for both original intents and create the final list of possible Intents with one new Intent for each retrieved activity like this:
List<Intent> yourIntentsList = new ArrayList<Intent>();
List<ResolveInfo> l...
What is Java Servlet?
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A servlet is simply a class which responds to a particular type of network request - most commonly an HTTP request. Basically servlets are usually used to implement web applications - but there are also various frameworks which operate on top of servlets (e.g. Struts) to give a higher-level abst...
How to retrieve all keys (or values) from a std::map and put them into a vector?
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While your solution should work, it can be difficult to read depending on the skill level of your fellow programmers. Additionally, it moves functionality away from the call site. Which can make maintenance a little more difficult.
I'm not sure if you...