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Why is parenthesis in print voluntary in Python 2.7?
In Python 2.7 both the following will do the same
4 Answers
4
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Import error: No module name urllib2
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As stated in the urllib2 documentation:
The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error. The 2to3 tool will automatically adapt imports when converting your sources to Pyth...
What is a “symbol” in Julia?
Specifically:
I am trying to use Julia's DataFrames package, specifically the readtable() function with the names option, but that requires a vector of symbols.
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How to read file from relative path in Java project? java.io.File cannot find the path specified
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If it's already in the classpath, then just obtain it from the classpath instead of from the disk file system. Don't fiddle with relative paths in java.io.File. They are dependent on the current working directory over which you have totally ...
Why does sun.misc.Unsafe exist, and how can it be used in the real world?
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examples
VM "intrinsification." ie CAS (Compare-And-Swap) used in Lock-Free Hash Tables
eg:sun.misc.Unsafe.compareAndSwapInt
it can make real JNI calls into native code that contains special instructions for CAS
read more about CAS here ...
Explanation of JSONB introduced by PostgreSQL
PostgreSQL just introduced JSONB and it's already trending on hacker news . It would be great if someone could explain how it's different from Hstore and JSON previously present in PostgreSQL. What are its advantages and limitations and when should someone consider using it?
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How exactly does the “Specific Version” property of an assembly reference work in Visual Studio?
...ad a closer look at the "Specific Version" property of assembly references in Visual Studio 2010. After a few experiments with unexpected results I set out to learn as much as possible about how the property works. Even SO, it appears to me, does not have all the answers, so here is my attempt at se...
How to drop columns by name in a data frame
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You should use either indexing or the subset function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operat...
Arrays, heap and stack and value types
In the above code, is new int[100] generating the array on the heap? From what I've read on CLR via c#, the answer is yes. But what I can't understand, is what happens to the actual int's inside the array. As they are value types, I'd guess they'd have to be boxed, as I can, for example, pass myInte...
How to calculate “time ago” in Java?
In Ruby on Rails, there is a feature that allows you to take any Date and print out how "long ago" it was.
30 Answers
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