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Difference between abstract class and interface in Python
... @L.DeLeo - are you sure your notion of has-a vs. is-a is correct? I generally view the distinction as has-a = member variable vs. is-a = inheritance (parent class or interface). Think Comparable or List in Java; those are is-a relationships, regardless of whether they're interfaces or abstract cl...
What kind of leaks does automatic reference counting in Objective-C not prevent or minimize?
... platforms, memory leaks are often caused by unreleased pointers. Traditionally, it has always been of utmost importance to check your allocs, copies and retains to make sure each has a corresponding release message.
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How to apply a function to two columns of Pandas dataframe
Suppose I have a df which has columns of 'ID', 'col_1', 'col_2' . And I define a function :
12 Answers
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`if __name__ == '__main__'` equivalent in Ruby
...f there isn't really a good, clean way of doing this.
EDIT: Found it.
if __FILE__ == $0
foo()
bar()
end
But it's definitely not common.
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Why isn't `int pow(int base, int exponent)` in the standard C++ libraries?
... of power functions (and others). C++11 [c.math] /11 states, after listing all the float/double/long double overloads (my emphasis, and paraphrased):
Moreover, there shall be additional overloads sufficient to ensure that, if any argument corresponding to a double parameter has type double or an...
What is the difference between user and kernel modes in operating systems?
... CPU instruction and
reference any memory address. Kernel
mode is generally reserved for the
lowest-level, most trusted functions
of the operating system. Crashes in
kernel mode are catastrophic; they
will halt the entire PC.
User Mode
In User mode, the executing code has no abili...
viewWillDisappear: Determine whether view controller is being popped or is showing a sub-view contro
...trollers property) has been updated by the time that viewWillDisappear is called.
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Always pass weak reference of self into block in ARC?
... be the cause of these blocks retaining self and keeping it from being dealloced ? The question is, should I always use a weak reference of self in a block ?
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Why do loggers recommend using a logger per class?
...ogger.DebugFormat("File not found: {0}", _filename); // Logger determines caller
-- or --
Logger.DebugFormat(this, "File not found: {0}", _filename); // Pass in the caller
Using the second example, the Logger would need to build a stack trace to see who was calling it or your code would always h...
Received an invalid column length from the bcp client for colid 6
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Specifically, if you have any columns that are VARCHAR smaller than 4, watch out for NULL in your data getting misinterpreted as the 4char string "NULL"
– CrazyPyro
Feb 11 at 8:13
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