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Why do we use __init__ in Python classes?
...Spot is a bit of a cripple and is mostly yellow. The __init__ function is called a constructor, or initializer, and is automatically called when you create a new instance of a class. Within that function, the newly created object is assigned to the parameter self. The notation self.legs is an attrib...
Redirect stdout to a file in Python?
...t it back when you're done, sys.stdout = stdout. That way if you're being called from a function that uses print you don't screw them up.
– mgold
Dec 20 '12 at 15:06
4
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Elegant way to check for missing packages and install them?
...}
}
# Then try/install packages...
foo( c("ggplot2" , "reshape2" , "data.table" ) )
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What does the caret operator (^) in Python do?
...his way:
1000 # 8 (binary)
0011 # 3 (binary)
---- # APPLY XOR ('vertically')
1011 # result = 11 (binary)
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What is a mutex?
...ion (In critical section multi threads share a common variable, updating a table, writing a file and so on), it releases the lock when it leaves critical section.
What is a Race Condition?
A race condition occurs when two or more threads can access shared data and they try to change it at the same t...
Error handling in Bash
...kens code's predictability and portability).
You can either let the trap call error for you (in which case it uses the default exit code of 1 and no message) or call it yourself and provide explicit values; for instance:
error ${LINENO} "the foobar failed" 2
will exit with status 2, and give an ...
实现一个简单的服务端推方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...for field, value in pairs(args) do
if type(value) ~= "table" then
config:set(field, value);
end
end
ngx.say("OK");
ngx.exit(ngx.HTTP_OK);
end
';
}
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Return empty cell from formula in Excel
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Maybe this is cheating, but it works!
I also needed a table that is the source for a graph, and I didn't want any blank or zero cells to produce a point on the graph. It is true that you need to set the graph property, select data, hidden and empty cells to "show empty cells as ...
hasNext in Python iterators?
...thod to put the first element back after I have checked that it exists by calling next().
– Giorgio
Dec 24 '12 at 20:26
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How do I get my Python program to sleep for 50 milliseconds?
...rity, CPU load avg, available memory, and a plethora of other factors make all calls imprecise. The busier the system is, the higher the imprecision.
– David
Jan 28 '19 at 18:44
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